Head to head · October 2026 cycle
Grammarly vs StealthGPT
StealthGPT finished 13.2 points ahead of Grammarly in the October 2026 cycle, 74.50 to 61.29, ranking #2 against #14 in a field of 14. StealthGPT scored higher on 6 of 6 detectors and 6 of 6 writing categories. Grammarly came out ahead on meaning preservation (85.5 vs 61.8) and consistency across categories (93.6 vs 90.9).
- Detectors
- 0 – 6
- Categories
- 0 – 6
- Components
- 2 – 2 (1 tie)
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. StealthGPT 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. StealthGPT has finished ahead in 4 of 5 shared cycles.
| Cycle | Grammarly | StealthGPT | Margin |
|---|---|---|---|
| October 2026 | 61.29 #14 | 74.50 #2 | → 13.2 |
| September 2026 | 60.35 #12 | 65.10 #9 | → 4.7 |
| August 2026 | 52.91 #11 | 45.55 #12 | ← 7.4 |
| July 2026 | 53.38 #12 | 61.52 #8 | → 8.1 |
| June 2026 | 56.50 #12 | 71.47 #7 | → 15.0 |
Where each one wins
Every measure above that one tool won outright, largest margin first within each group.
Grammarly
2 wins- Meaning preservation Score 85.5 vs 61.8
- Consistency Score 93.6 vs 90.9
StealthGPT
14 wins- Bypass rate Score 88.1 vs 38.1
- Readability Score 72.6 vs 72.2
- GPTZero Detector 94.8 vs 3.0
- Pangram Detector 69.9 vs 0.0
- Originality.ai Detector 96.3 vs 52.4
- Copyleaks Detector 100.0 vs 58.2
- ZeroGPT Detector 77.3 vs 43.7
- Winston AI Detector 90.4 vs 71.6
- News Article Category 84.0 vs 68.0
- Blog Post Category 70.4 vs 56.8
- and 4 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 claude-sonnet-5-5 · 293 words
# Grow Your First Garden. Without the Guesswork.
## SproutPlan helps you plant, tend, and harvest your own backyard vegetables, step by step.
You've pictured it: tomatoes ripening on the vine, fresh basil a few steps from the kitchen, dinner pulled straight from your own yard. But where do you start? How much sun do you need? When do you plant? Why did last year's lettuce bolt?
SproutPlan answers every question, built around your yard and your schedule.
---
### Your Garden, Designed in Minutes
Tell us your zip code, your space, and how much sun you get. SproutPlan creates a custom garden layout with the right vegetables for your climate, spaced correctly and grouped with companion plants that help each other thrive.
### Know Exactly What to Do, and When
Get a personalized calendar with simple reminders for sowing, watering, feeding, and harvesting. Our frost-date alerts protect your seedlings before the weather turns.
### Fix Problems Fast
Yellow leaves? Strange spots? Snap a photo and get a diagnosis with clear, organic treatment options. No more late-night forum scrolling.
### Built for Beginners, Loved by Growers
- **Smart plant recommendations** matched to your skill level - **Weekly checklists** that take 15 minutes or less - **Harvest tracking** to see what worked and plan next season - **Budget estimator** so you know costs before you buy a single seed
---
> "I'd killed every plant I'd ever owned. Three months with SproutPlan and I'm giving zucchini to the neighbors." — Dana R., first-time gardener
---
### Start Free for 14 Days
No credit card required. Build your garden plan today and plant with confidence this weekend.
**[Start My Garden]**
Plans from $6/month after your trial. Cancel anytime.
*Your backyard is ready. Let's grow something.*
Show the full input Show less
361 words (input 293)
How to grow your first garden without having to make guesses.
SproutPlan will help you to plant, look after, and harvest your own vegetables in your backyard, in a step-by-step manner.
You've already imagined it—tomatoes ripening on the vine, fresh basil just a few steps away from the kitchen, dinner taken directly from your own garden. But then comes the question: how much sunlight do you need? When should you plant it? And why did the lettuce from last year bolt?
SproutPlan takes on all the questions, taking into account your garden and your timetable.
---
### Your Garden, Designed in Minutes
Please give us your zip code, the amount of space you have, and the level of sunlight you receive. SproutPlan will then produce a personalised garden plan featuring the suitable vegetables for your climate, with the plants spaced properly and grouped together with companion plants that help one another to thrive.
### Know Exactly What to Do, and When
You can obtain a personalized calendar that includes simple reminders about sowing, watering, feeding, and harvesting; our frost-date warnings will safeguard your seedlings before the weather changes.
### Fix Problems Fast
If the leaves are yellow or there are odd spots, take a photo and get a diagnosis together with clear, natural treatment options—no need to scroll through forums late at night.
### Built for Beginners, Loved by Growers
- **Smart plant recommendations** matched to your skill level - **Weekly checklists** that take 15 minutes or less - **Harvest tracking** to see what worked and plan next season - **Budget estimator** so you know costs before you buy a single seed
---
—I've killed every plant that I ever owned; but after three months using SproutPlan I'm now giving some zucchinis to my neighbours.— Dana R., a first-time gardener
---
### Start Free for 14 Days
You don’t need a credit card. Create your garden plan today and then you can plant with confidence this weekend.
**[Start My Garden]**
You can choose the plan at a rate of $6 per month after the trial period; cancellation is possible at any time.
Your backyard is all set now; let's grow something.
Show the full output Show less
- GPTZero0.00caught
- Pangram0.00caught
- Winston AI0.72passed
- ZeroGPT0.48caught
- Copyleaks1.00passed
- Originality.ai0.20caught
Passed 2 of 6 detectors.
Every Grammarly run in October 2026 →227 words (input 293)
Your Garden, Designed in Minutes
Tell us your zip code, the size of your gardening space, and how much sun it gets. SproutPlan does the rest. Get a custom garden design full of vegetables that’ll thrive in your area, laid out to maximize growth in your available space. We’ll tell you what to plant, where, when, and how much – no guesswork necessary.
Know Exactly What to Do, and When
We’ll customize a calendar of tasks to match your garden design, sending reminders for planting, feeding, watering, and harvesting. Know the ideal times to sow seeds for a head start, when to expect frost, what’s ready to eat, and more.
“I'd killed every plant I'd ever owned. Three months with SproutPlan and I'm giving zucchini to the neighbors.” -Dana R., first-time gardener
Fix Problems Fast
See yellowing leaves or holes chewed in your prized tomato plant? Snap a photo and send it to SproutPlan. Get an ID and organic treatment options. No hours of forum-hopping necessary.
Great for beginners and a favorite of growers:
Recommendations that match your experience and goals
A budgeting tool helps you invest before buying
Easy-to-follow checklists keep weekly maintenance to 15 minutes or less
Track your bountiful harvest!
Start Free for 14 Days
Start your 14-day free trial today. There is no credit card necessary. From $6/month after trial period. Cancel anytime.
Show the full output Show less
- GPTZero1.00passed
- Pangram1.00passed
- Winston AI0.98passed
- ZeroGPT0.91passed
- Copyleaks1.00passed
- Originality.ai1.00passed
Passed 6 of 6 detectors.
Every StealthGPT 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 StealthGPT?
StealthGPT finished 13.2 points ahead of Grammarly in the October 2026 cycle, 74.50 to 61.29, ranking #2 against #14 in a field of 14. StealthGPT scored higher on 6 of 6 detectors and 6 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 StealthGPT?
StealthGPT posted the higher bypass rate, 88.1 vs 38.1, and scored higher on 6 of 6 detectors. StealthGPT led on GPTZero, Originality.ai, Copyleaks, Winston AI, ZeroGPT and Pangram.
Do Grammarly and StealthGPT keep the original meaning?
Grammarly preserved meaning better, 85.5 vs 61.8 on our 0–100 similarity scale. On readability, StealthGPT rated higher, 72.6 vs 72.2. Penalties this cycle: Grammarly −3.0, StealthGPT −3.0.