Head to head · October 2026 cycle
Grammarly vs Undetectable.ai
Undetectable.ai finished 9.9 points ahead of Grammarly in the October 2026 cycle, 71.18 to 61.29, ranking #3 against #14 in a field of 14. Undetectable.ai scored higher on 6 of 6 detectors and 5 of 6 writing categories. Grammarly came out ahead on penalties (−3.0 vs −5.0), readability (72.2 vs 63.9) and news article prompts (68.0 vs 61.4).
- Detectors
- 0 – 6
- Categories
- 1 – 5
- Components
- 4 – 1
30 prompts · Last tested · Methodology v1.3.0
Score components
What the overall score is made of: bypass rate weighs 42%, meaning preservation 32%, readability 16%, consistency across categories 10%. Output-quality penalties come off the total. How scoring works →
Detector by detector
Share of each tool's outputs that a detector classified as human-written. Undetectable.ai took 6 of 6.
Writing categories
Category score per writing context: bypass credit only for real rewrites, blended with the category's own meaning preservation and readability. Small categories swing; the prompt count is shown on each row. How category scores work →
Head-to-head history
Overall score in every cycle both tools were tested. Undetectable.ai has finished ahead in 5 of 5 shared cycles.
| Cycle | Grammarly | Undetectable.ai | Margin |
|---|---|---|---|
| October 2026 | 61.29 #14 | 71.18 #3 | → 9.9 |
| September 2026 | 60.35 #12 | 71.75 #6 | → 11.4 |
| August 2026 | 52.91 #11 | 61.49 #8 | → 8.6 |
| July 2026 | 53.38 #12 | 72.17 #2 | → 18.8 |
| June 2026 | 56.50 #12 | 80.09 #5 | → 23.6 |
Where each one wins
Every measure above that one tool won outright, largest margin first within each group.
Grammarly
5 wins- Penalties Score −3.0 vs −5.0
- Readability Score 72.2 vs 63.9
- Meaning preservation Score 85.5 vs 79.2
- Consistency Score 93.6 vs 93.0
- News Article Category 68.0 vs 61.4
Undetectable.ai
12 wins- Bypass rate Score 74.6 vs 38.1
- GPTZero Detector 85.0 vs 3.0
- ZeroGPT Detector 83.8 vs 43.7
- Originality.ai Detector 88.7 vs 52.4
- Copyleaks Detector 87.9 vs 58.2
- Winston AI Detector 98.5 vs 71.6
- Pangram Detector 3.5 vs 0.0
- Discussion Board Category 69.4 vs 50.1
- Application Essay Category 76.4 vs 62.3
- Marketing Copy Category 71.5 vs 57.7
- and 2 more
Same prompt, both outputs
Both tools were given this AI-written passage in the October 2026 cycle. Below it is what each one returned. This prompt was picked by a fixed rule, not by how the tools scored.
AI-written input
Every tool on this prompt →Landing Copy · Marketing Copy · written by gemini-3-8-flash · 270 words
**Headline: Turn Your Backyard into a Grocery Aisle—Zero Guesswork Required.**
**Subheadline:** Meet SproutPlan: The smart gardening assistant that tells you *what* to plant, *where* to plant it, and *when* to water, tailored entirely to your microclimate.
***
**Tired of dead plants and wasted weekends?** Starting a vegetable garden shouldn't require a master’s degree in horticulture. Whether you have an empty suburban plot or two raised beds on a patio, SproutPlan eliminates the trial-and-error so you can harvest crisp, organic produce this season.
**How SproutPlan Works:**
* **Custom Drag-and-Drop Layouts:** Input your yard’s dimensions and sunlight. Our algorithmic garden planner automatically places companion plants together—like basil next to tomatoes—to naturally deter pests and maximize your yield. * **Hyper-Local Planting Calendars:** Frost dates are unpredictable. SproutPlan syncs with your local weather station, sending automated push alerts when it’s the exact right weekend to sow seeds or transplant seedlings. * **Daily Smart Care Tasks:** Forget generic advice. Get a simplified daily checklist on your phone: *"Water the lettuce (dry spell incoming),"* or *"Prune tomato suckers today."*
***
**"I killed three tomato plants last year. This year, my family hasn't bought salad greens in two months. SproutPlan made it foolproof."** — *Elena R., First-Time Gardener*
***
**Fresh Food is Just One Click Away.** Stop scrolling through conflicting internet forums. With SproutPlan in your pocket, you’ll know precisely what to do every single day, from tiny seed to full harvest dinner.
Save money on groceries, eat cleaner food, and fall in love with the easiest hobby you've ever started.
**[Start Your Free 14-Day Trial]** *No credit card required. Ready for planting zones 3 through 11.*
Show the full input Show less
349 words (input 270)
**Headline: Turn your backyard into a grocery aisle with no guesswork at all.**
**Subheadline:** Introducing SproutPlan: a smart gardening assistant that will tell you what to plant, where to plant it, and when to water, specifically taking into account your microclimate.
***
Bored with dead plants and wasted weekends? You don't need a master's degree in horticulture if you want to start a vegetable garden. Whether you have an empty plot in a suburban area or just two raised beds on your patio, SproutPlan removes the need for trial and error so that you can harvest some crisp, organic produce this season.
**How SproutPlan Works:**
* **Custom Drag-and-Drop Layouts:** Enter the measurements of your yard and information about the sunlight it receives. The algorithm used by our garden planner will then automatically position companion plants next to one another—for example, basil alongside tomatoes—in order to naturally repel pests and get the most from your harvest. * **Hyper-Local Planting Calendars:** Since frost dates are unpredictable, SproutPlan connects with the nearest weather station and sends out automatic push notifications when the correct weekend has arrived for sowing seeds or transplanting seedlings. * **Daily Smart Care Tasks:** Don't just follow general advice; get a simplified daily checklist on your phone, for example, "Water the lettuce (a dry period is coming)", or "Prune the tomato suckers today".
***
Last year I killed three tomato plants and this year my family has not bought salad greens for two months; SproutPlan made it foolproof. *Elena R., First-Time Gardener*
***
You can get fresh food with just one click. There's no point in browsing the different internet forums. By having SproutPlan with you, you'll know exactly what to do each and every day, from sowing the seed to the meal when the crop is fully harvested.
You can cut down on your grocery bills, eat healthier food, and end up falling in love with the simplest hobby you have ever taken up.
**[Start Your Free 14-Day Trial]** You don’t need a credit card and the product is suitable for use in planting zones 3 to 11.
Show the full output Show less
- GPTZero0.00caught
- Pangram0.00caught
- Winston AI0.90passed
- ZeroGPT0.39caught
- Copyleaks0.00caught
- Originality.ai0.19caught
Passed 1 of 6 detectors.
Every Grammarly run in October 2026 →372 words (input 270)
**Headline: Turn Your Backyard into a Grocery Aisle—Zero Guesswork Required.**
**The Gardening Assistant for Your Yard and Climate.**
***
**Tired of dead plants and wasted weekends?** Don’t let your lack of horticultural knowledge to get in the way of your growing your own fresh vegetables. Whether you have a large suburban garden or a couple of raised beds on a patio, SproutPlan will help you to grow and harvest your own fresh, organic produce within a season or two.
**How SproutPlan Works:**
* **Create Custom Planting Plans**: Choose from a variety of vegetables and fruit and create a custom plan for your yard. You can choose the specific plants you want to grow and the space where you want them to grow. The SproutPlan algorithm will then choose the best companion plants for you and place them in the optimal locations in your yard for maximum growth and pest prevention. * **Hyper-Local Planting Calendars:** Our planting calendars are tied to your local weather station and let you know when it’s time to plant, as well as when it’s time to take specific plants inside to protect them from frost. We send you automatic push notifications when it’s time to sow seeds or to transplant seedlings. * **Daily Smart Care Tasks:** Your vegetable garden needs daily care. Get smart daily care tasks like, "Water the lettuce (dry spell incoming)" or "Prune tomato suckers today" – on your phone whenever you need them.
***
**"I killed three tomato plants last year. This year, my family hasn't bought salad greens in two months. SproutPlan made it foolproof."** — *Elena R., First-Time Gardener*
***
**Fresh Food is Just One Click Away.** Stop searching through overfilled online forums for confusing information with SproutPlan! This powerful tool in the palm of your hand will supply you with the exact steps you need to continue growing and harvesting produce from your garden from seed to table.
Save money on groceries, eat cleaner food, and fall in love with the easiest hobby you've ever started. Start your Free 14-Day Trial of SproutPlan today! No credit card required. We support planting zones 3 through 11.
**[Start Your Free 14-Day Trial]** *No credit card required. Ready for planting zones 3 through 11.*
Show the full output Show less
- GPTZero0.84passed
- Pangram0.00caught
- Winston AI1.00passed
- ZeroGPT0.75passed
- Copyleaks0.00caught
- Originality.ai0.94passed
Passed 4 of 6 detectors.
Every Undetectable.ai run in October 2026 →Each chip is one detector's score for that output, from 0 (AI) to 1 (human). A score of 0.50 or higher counts as a pass and shows green; below that the detector caught it and the chip shows red.
Questions people ask
Is Grammarly better than Undetectable.ai?
Undetectable.ai finished 9.9 points ahead of Grammarly in the October 2026 cycle, 71.18 to 61.29, ranking #3 against #14 in a field of 14. Undetectable.ai scored higher on 6 of 6 detectors and 5 of 6 writing categories. Both tools ran the same 30 prompts, scored by the same 6 detectors, under methodology v1.3.0; every input, output and verdict is published.
Which bypasses AI detectors better, Grammarly or Undetectable.ai?
Undetectable.ai posted the higher bypass rate, 74.6 vs 38.1, and scored higher on 6 of 6 detectors. Undetectable.ai led on GPTZero, Originality.ai, Copyleaks, Winston AI, ZeroGPT and Pangram.
Do Grammarly and Undetectable.ai keep the original meaning?
Grammarly preserved meaning better, 85.5 vs 79.2 on our 0–100 similarity scale. On readability, Grammarly rated higher, 72.2 vs 63.9. Penalties this cycle: Grammarly −3.0, Undetectable.ai −5.0.