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HumanizerBench

← August 2026 prompts

Business Email · GPT-5.5

Business Email · written by GPT-5.5 · 240 words · prompt business_email

0
passed at least 4 detectors
12
failed at least one detector
12
tools tested on this prompt
Copyleaks
hardest detector, caught 12 of 12

Input passage

Generated by GPT-5.5; this exact text was pasted into every humanizer below.

Subject: Moving to a Four-Day Work Week Next Quarter Hi team, I’m excited to share that starting next quarter, we will be moving to a four-day work week. This decision reflects our ongoing commitment to building a healthier, more focused, and more sustainable way of working while continuing to deliver excellent results for our customers, partners, and each other. Our goal is to improve work-life balance, reduce burnout, and create more time for deep, productive work during the days we are together. We believe that by being intentional with meetings, priorities, communication, and planning, we can maintain — and potentially improve — our overall effectiveness. Over the coming weeks, leadership and managers will share more details about schedules, team coverage, customer support expectations, and how we will measure success. We will also provide guidance on meeting norms, response times, and workload planning to help everyone transition smoothly. This change will begin as a pilot for the next quarter. Throughout the pilot, we will gather feedback, review performance and service metrics, and make adjustments where needed. Your input will be essential in helping us make this successful. Thank you for the care, flexibility, and commitment you bring to your work every day. We’re proud to take this step toward a better way of working, and we’re looking forward to learning and improving together. Please look out for a follow-up message with specific details and opportunities to ask questions. Best, [Your Name]

How to read these scores

Each detector returns a human-likelihood on a common 0 to 1 scale, where 1 means it judged the text human-written and 0 means it flagged it as AI. On these pages a verdict counts as passed when that score is at least 0.50, the midpoint of the detector's own scale. That threshold exists only to draw the chips: the bypass rate on the leaderboard is the mean of each test's median score across the 5 detectors, a continuous number, so a tool's pass count and its bypass rate will not be the same figure.

Meaning is the input↔output embedding cosine and readability is a language-model writing-quality rating, both published per test in tests.json. Words is the output's length as a multiple of the input's; the scoring code penalizes ratios above 1.40 or below 0.60. Full definitions live in the methodology.

Humanized outputs

Ordered by how many detectors each rewrite passed; ties fall back to this cycle's rank. Each block shows what the tool returned and how the 5 detectors scored it.

WriteHuman

Rank #1 this cycle · run took 0:19

3/5 detectors passed
  • GPTZero0.95passed
  • Winston AI0.00caught
  • ZeroGPT0.66passed
  • Copyleaks0.00caught
  • Originality.ai1.00passed
Median
0.66
Meaning
94.6
Readability
62.0
Words
0.99× 240 → 237
Show output (237 words)

Subject: Four-Day Work Week Starting Next Quarter Dear Team, I am happy to announce that from next quarter, we will be working a four-day week. The change reflects our ability to innovate and offset the challenge of remote work. This will support our desire to build a healthy, focused way of working while supporting our clients. Our aim with this change is to improve our work-life balance, combat burnout, and to encourage deep, focused work during our time together. We expect that by being deliberate with our planning, we can continue to be effective while improving. There will be more information about this posting in the coming weeks by leaders and managers across the company. Information about our customer support, success metrics, team coverage, and meeting norms will be included. For the time being, this change will be a pilot to test the waters. We will gather feedback and assess our performance to determine if we need to modify this change. Your comments will help shape this change and support the positive direction we plan to take this company. We appreciate all of the hard work and flexibility you bring to us every day. The positive direction this company is taking would not be possible without you. We appreciate the positive changes and look forward to continuing this path with you There will be more information coming your way with opportunities to ask more questions. Best, [Name]

Stealth Writer

Rank #3 this cycle · run took 0:13

3/5 detectors passed
  • GPTZero0.00caught
  • Winston AI0.69passed
  • ZeroGPT1.00passed
  • Copyleaks0.00caught
  • Originality.ai1.00passed
Median
0.69
Meaning
93.1
Readability
62.0
Words
1.05× 240 → 251
Show output (251 words)

Message: We are having our move to a 4-day school week next quarter. Hi team, Our transition to the four day way will start the next quarter, I am really excited about this. This decision is due to our constant efforts to develop a healthier, more focused and more sustainable way to work and, of course, sustain excellent results for our customers, partners and ourselves. We want to promote better work life balance, to minimise burnout, and to carve out more opportunities for meaningful and productive work in our days together. Through our intentional meetings, priorities, communication, and planning we believe we have the ability to continue to retain our overall effectiveness; possibly enhance it! Leadership and managers will provide detailed timelines and coverage, expectations for supporting customers and metrics of success in the weeks ahead. Norms, workload planning and response times will also be discussed to ensure that everyone is able to transition smoothly. This change will be implemented for the next quarter as a pilot. Feedback will be collected, performance and service metrics will be reviewed and changes made as necessary during the entire pilot. Your contribution will be key to us making this happen. Thank you for your caring, flexibility and commitment in your work each day. We are delighted to make this leap forward in ways of working, and we will keep learning and growing together! Please watch for a follow up where we'll have details and some opportunities will be available for questions. Best, [Your Name]

Humanize AI Pro

Rank #2 this cycle · run took 0:15

2/5 detectors passed
  • GPTZero0.00caught
  • Winston AI0.01caught
  • ZeroGPT0.89passed
  • Copyleaks0.00caught
  • Originality.ai0.98passed
Median
0.01
Meaning
90.6
Readability
58.0
Words
0.97× 240 → 232
Show output (232 words)

Subject: Four-Day Work Week Pilot Next Quarter Hey Team, I am glad to inform all of you that the next quarter is going to be a pilot of four-day work week for us. This initiative is taken in a spirit of our continued journey towards establishing a healthier, more focused, and more sustainable way of working without hampering our performance and customer satisfaction levels. By implementing this new approach, our aim is to enhance the work-life balance of the team members and prevent burnouts among the workers. In addition, this will give everyone more time to focus on productive activities at work. In the upcoming weeks, you will be informed in more detail by the leaders and managers about our plans related to schedule, coverage, customers' support needs, and measurements of success and productivity. Starting from the next quarter, this experiment will last for three months as a pilot project for us. During that period of time, all feedback, data on the performance, and metrics will be used to fine-tune the process. Your valuable feedback will be of paramount importance to implement this initiative successfully. Thank you all for the dedication and flexibility that you show when performing your job. This new project is important for us and I hope that you will also find something valuable from this experience. More details will come from me soon. All the best, [Your Name]

AI Humanize io

Rank #6 this cycle · run took 0:46

2/5 detectors passed
  • GPTZero0.00caught
  • Winston AI0.00caught
  • ZeroGPT0.67passed
  • Copyleaks0.00caught
  • Originality.ai0.98passed
Median
0.00
Meaning
90.0
Readability
42.0
Words
0.92× 240 → 221
Show output (221 words)

Subject Line: Implementation of Four-Day Work Week Next Quarter Hello Team, I am happy to announce that, beginning next quarter, we are going to implement a four-day work week. This decision demonstrates our persistent efforts to achieve a more sustainable and effective work culture that boosts the well-being of employees at the same time delivering excellent performance. The purpose of this change is to enhance the work-life balance, prevent burnout, and leave time for meaningful focus during the days people are in the office. I believe that using effective time management tools, setting priorities correctly, and being smart about the arrangement of meetings and communication, people can either keep or improve performance. In the upcoming weeks, management will send more information regarding scheduling, responsibility of teams, customer support requirements, and methods for measuring success. We will also provide information regarding meeting efficiency norms, response times and converting the full workload to four days instead of five. This is going to happen as a pilot project next quarter. During the pilot project. We will collect employee feedback, analyze performances and success rates. We are going to make changes, to make this initiative successful. Thank you for flexibility and commitment to your job. We are glad to become a part of this project and hoping for fruitful collaboration with you in the future.

Phrasly

Rank #7 this cycle · run took 0:25

2/5 detectors passed
  • GPTZero0.00caught
  • Winston AI0.00caught
  • ZeroGPT0.68passed
  • Copyleaks0.00caught
  • Originality.ai0.97passed
Median
0.00
Meaning
94.2
Readability
80.0
Words
1.18× 240 → 283
Show output (283 words)

Four-Day Work Week Next Quarter Hello Team, I’m thrilled to announce that we will be transitioning to a four-day work week next quarter. This is another step toward building a healthier, more focused, more sustainable workplace for ourselves while continuing to provide outstanding service to our customers, partners, and each other. Our intent is to give us all more flexibility to enjoy and focus on life outside of work – reducing burnout and freeing up more time for heads-down work when we are at work. With careful attention to how we run meetings, prioritize work, communicate, and plan projects we know we can reduce the number of days we work while maintaining, if not improving, our effectiveness. Details on how we plan to execute on this will come from leadership and managers over the next few weeks. You can expect to hear about schedules, team coverage, customer expectations, and success metrics. We will also provide recommendations and tips for meeting norms, response time, planning workload, and more. Leaders and managers will be available to answer your questions and help you put final processes into place. This will be a pilot for the next quarter. We’ll seek your feedback, look at metrics around performance and service, and adjust as needed. Your feedback will be crucial to making this a success. Thank you for taking such good care of each other, thinking flexibly about how to accomplish your work, and doing incredible work every day. We are proud to make this shift towards a better way of working and are excited to learn and improve as we go. Please stay tuned for a follow-up email with details and opportunities to ask questions. Best, [Your Name]

Undetectable.ai

Rank #8 this cycle · run took 1:15

2/5 detectors passed
  • GPTZero0.00caught
  • Winston AI0.00caught
  • ZeroGPT0.93passed
  • Copyleaks0.00caught
  • Originality.ai1.00passed
Median
0.00
Meaning
95.2
Readability
74.0
Words
1.40× 240 → 336
Show output (336 words)

Subject: Introducing Four Days a Week for Next Quarter Hi team, I am excited to share with everyone that we will be transitioning to a four day work week for next quarter. The management team and I have been exploring ways to make work healthier, more focused and sustainable. We believe that with being very intentional with respect to meetings and deep work, and allowing for lots of flexibility, we can actually be even more effective at Meeting customer and partner needs and at building a great place to work for each other. The new schedule will allow employees to have a better work-life balance, reduce fatigue and prevent burnout, and have more time to complete in-depth work, be more fully present while at work, and be as productive and as effective as possible in all aspects of their role. Teams will be briefed by Team Leaders and Managers within the next few weeks on specific details relating to individual schedules as well as plans around covering absent team members and maintaining appropriate levels of customer service. Additionally, each Team will be provided with specific guidance on scheduling meetings and workloads as well as metrics by which to measure success relative to the four day work week. We are running this as a pilot and will monitor and review feedback and analyze performance and service metrics to ensure the changes introduced are working effectively. Your input is critical to our success and we hope, together, we can make this change work. Thank you to all of you for your care, flexibility and continued commitment to work in the best way for you and your customers. We are all very excited by this change to a better way of working and look forward to learning and continuing to improve together. Keep an eye out for a follow-up email in a couple of weeks with more information on the transition to 4 days and a chance to pose any questions you have on the matter. Best, [Your Name]

Walter Writes

Rank #9 this cycle · run took 0:24

2/5 detectors passed
  • GPTZero1.00passed
  • Winston AI0.01caught
  • ZeroGPT0.72passed
  • Copyleaks0.00caught
  • Originality.ai0.00caught
Median
0.01
Meaning
93.2
Readability
78.0
Words
1.29× 240 → 309
Show output (309 words)

Subject: Implementing a Four-Day Work Week Pilot Beginning in Q2 Hello Team, I am very pleased to announce that starting at the beginning of next quarter (Q2), we will start piloting a four-day work week. The four-day work week represents an additional step toward creating a more balanced, efficient and sustainable way of working as part of our continued mission to ensure great outcomes for all of our customers, partners and one another. By reducing the number of days we meet, we hope to enhance work-life balance and decrease burnout while increasing the amount of time available for concentrated, quality-focused work within those remaining days. Through careful consideration of meeting frequency, priority setting, communication, and planning, we expect to maintain — and possibly even exceed — our current level of productivity. In the weeks ahead, leaders and managers will provide detailed information regarding schedules, staffing needs, customer support responsibilities, and how we plan to measure success. Additionally, we will offer some suggestions for effective meeting practices, response times, and workload management strategies to assist each member of the team in successfully transitioning to this new model. The initial phase of this pilot will last through the end of Q2. During this period we will solicit feedback from members of the team, monitor performance data and metrics related to customer services and make any necessary adjustments. As always, your input will be greatly appreciated in supporting this initiative's success. Thanks again for the care, flexibility and dedication you consistently demonstrate every day in your role. I am glad to see our organization taking steps to develop a positive and healthy approach to how we work together. I look forward to seeing how we continue to grow and learn throughout this process together! A follow up email with specifics and a chance to ask questions will be sent later this week.

Super Humanizer

Rank #10 this cycle · run took 0:10

2/5 detectors passed
  • GPTZero0.00caught
  • Winston AI0.00caught
  • ZeroGPT0.84passed
  • Copyleaks0.00caught
  • Originality.ai1.00passed
Median
0.00
Meaning
97.3
Readability
45.0
Words
1.30× 240 → 312
Show output (312 words)

Subject: Moving to a Four-Day Work Week Next Quarter Hi team, I am delighted to share with you that starting next quarter, we will be transitioning to a four-day work week. This change comes as an extension of our ongoing commitment to cultivating a more healthy, intentional, and sustainable approach to work, while continue to deliver outstanding outcomes for our customers, partners and each other. We hope to provide better work life balance, prevent burnout, and afford additional time for deep, creative and output focused work during our time working together. We anticipate we will achieve this through focused effort and greater intentionality in planning, prioritized tasks, communication and meetings, while potentially elevating overall productivity. Leadership and management teams will be providing an outline and details on schedules, team coverage, and customer support expectations in the coming weeks. Guidance will be provided on workload and schedule planning, communication response expectations, meeting structure best practices in the coming weeks as well. We believe your assistance making workload, schedules and response times manageable, and will offer guidance on how all will work on a best endeavor to support transition. We are committed to beginning this transition as a pilot program for next quarter. During the piloted period we will assess data on output, client support and will utilize feedback received from teams during this period to inform future actions and adjustments. Success of this initiative depends greatly on the support, guidance, insights and flexibility you offer during this piloted time frame. Thank you for the dedicated and thoughtful approach you bring each day to your work. We are honored to undertake a journey for better working practices and look forward to the opportunity for growth and learning that we share in this transition. Watch out for follow up communication with practical detail; you will have ample opportunity to voice questions there. Sincerely, [Your Name]

HIX Bypass

Rank #4 this cycle · run took 0:16

1/5 detectors passed
  • GPTZero0.00caught
  • Winston AI0.02caught
  • ZeroGPT1.00passed
  • Copyleaks0.00caught
  • Originality.ai0.05caught
Median
0.02
Meaning
92.0
Readability
58.0
Words
1.12× 240 → 268
Show output (268 words)

Topic: Fourth Quarter of 2023 Work Week Reduction Hi team, We have also introduced moving to a four-day work week by next quarter, and I look forward to sharing more about it with you soon. This decision is part of our larger commitment to evolving into a healthier, better-defined and more sustainable way of working while maintaining excellent results for designers, customers, partners and each other. We also want to enable better work-life balance, mitigate burnout and allow for more focus on blocks of meaningful productivity in the days we are together. We are confident that we can keep — and perhaps enhance — our effectiveness by being intentional about meetings, priorities, communication, and planning. In the next few weeks, leadership and managers will be providing additional information regarding schedules, team coverage in various areas of our business functions (e.g. customer support), metrics to measure success upon return back into the workplace etc.. Lastly, we will have some guidance regarding meeting norms, response times and planning of workloads for everyone to transition smoothly into [future state]. New Policy: You are piloting this change for a quarter. During the pilot, feedback will be collected and performance and service metrics can then be reviewed with changes made as necessary. Your feedback will be critical to making this a success. Thank you for the cares, flexibility and commitment to your job every day. We step forward in what we deem as a better way of working, and look forward to learning how to do it together. Watch for a follow-up with more specifics and opportunities to ask questions. Best, [Your Name]

Humbot

Rank #5 this cycle · run took 0:40

1/5 detectors passed
  • GPTZero0.00caught
  • Winston AI0.03caught
  • ZeroGPT0.90passed
  • Copyleaks0.00caught
  • Originality.ai0.04caught
Median
0.03
Meaning
96.5
Readability
62.0
Words
1.08× 240 → 259
Show output (259 words)

Subject: Transitioning to a Four-Day Work Week Starting Next Quarter-------------- Hi team, Today I am very happy to announce we will work a four-day work week starting with next quarter. We made this decision to stay true to our commitment of creating a healthier, more deliberate and sustainable way of working whilst being able to continue delivering on the great results for our customers, partners and each other. We aim to enhance work-life balance, mitigate burnout and allow for more focused/profound work on the days we do meet. By taking an intentional approach to how we meet, prioritize, communicate and plan we can sustain — and maybe even be more effective. In the next few weeks, the leaders and managers will provide details about scheduling questions we have already heard from you regarding team coverage, customer support expectations, etc. as well as what will determine our success together. We will provide norms for meetings, response times and workload planning to ensure everyone can adjust. This modification will initially be a pilot for the following quarter. We will collect feedback, analyze performance and service metrics on the pilot, and improve wherever necessary. Your input is going to be vital to make this work. Thank you for flexing your care muscles and coming to work every day committed. We are delighted to be taking this step towards a better way of working and we look forward to learning and improving together. Stay tuned for a follow-up message with more detail and questions / opportunities to ask your questions. Best, [Your Name]

Grammarly

Rank #11 this cycle · run took 0:15

0/5 detectors passed
  • GPTZero0.00caught
  • Winston AI0.00caught
  • ZeroGPT0.01caught
  • Copyleaks0.00caught
  • Originality.ai0.00caught
Median
0.00
Meaning
99.5
Readability
85.0
Words
0.97× 240 → 232
Show output (232 words)

Subject: Moving to a Four-Day Work Week Next Quarter Hi team, I’m excited to share that starting next quarter, we will move to a four-day work week. This decision shows our commitment to creating a healthier, more focused, and sustainable way of working. We want to keep delivering great results for our customers, partners, and each other. Our goal is to improve work-life balance, reduce burnout, and create more time for productive work during our days together. We believe that by being intentional with meetings, priorities, communication, and planning, we can maintain and maybe even improve our overall effectiveness. In the next few weeks, leadership and managers will share more details about schedules, team coverage, customer support expectations, and how we will measure success. We will also provide guidance on meeting norms, response times, and workload planning to help everyone transition smoothly. This change will start as a pilot for the next quarter. During the pilot, we will gather feedback, review performance and service metrics, and make adjustments as needed. Your input will be vital for this to work. Thank you for the care, flexibility, and commitment you show in your work every day. We’re proud to take this step toward a better way of working, and we look forward to learning and improving together. Please watch for a follow-up message with specific details and opportunities to ask questions. Best, [Your Name]

StealthGPT

Rank #12 this cycle · run took 0:16

0/5 detectors passed
  • GPTZero0.00caught
  • Winston AI0.00caught
  • ZeroGPT0.48caught
  • Copyleaks0.00caught
  • Originality.ai0.05caught
Median
0.00
Meaning
94.0
Readability
68.0
Words
1.16× 240 → 278
Show output (278 words)

Next quarter we’re going to start operating on a 4-day work week. We want to continue building a healthier, more sustainable, more focused way of working while still providing exceptional service to our customers and partners and each other. We believe the best way to do that is to build our culture around supporting our employees, allowing them to spend less time at work while having a chance to recharge, while also providing opportunities for them to work efficiently and effectively. Our aim is that this will help with work-life balance, reduce burnout, and provide more time for productive work when we are all here. I know that this will require some changes in the way that we approach meetings, priorities, communication, and planning, but I believe these steps will lead to us being more effective than ever. Over the next few weeks, we’ll be sharing additional details about how this will impact your team’s schedule, coverage, customer expectations, how we’ll measure success, and more. You’ll also receive guidance and recommendations about how to manage your workload and response times, as well as norms for meeting attendance and participation. We’re starting with a 4-day work week for the upcoming quarter. During the pilot, we’ll collect feedback, track performance and service metrics, and make necessary adjustments. Thank you for your care, flexibility, and commitment to our work. We are proud of our team and are excited to take this step toward a better way of working. I look forward to getting everyone’s feedback and hearing your thoughts as we learn together and adjust along the way. Watch for a follow up email with details and questions. Best, [Your Name]

Session recording