QuillBot Fails AI Detectors. SupWriter Doesn't.

Why Students Are Ditching QuillBot for Free Alternatives

We get it. You found QuillBot, thought it would make your ChatGPT essays undetectable, and then got flagged by Turnitin anyway. You're not alone.

Here's the thing most people miss: QuillBot is a paraphraser, not a humanizer. It swaps synonyms and rearranges sentence structure. That fooled AI detectors back in 2023. It doesn't anymore.

Turnitin rolled out an update in late 2025 that specifically targets paraphrasing tool patterns. QuillBot's output now gets flagged with purple highlights — the exact color Turnitin uses for "AI-assisted writing." We ran 50 essays through QuillBot and tested every single one. The result? Only 42% bypassed detection. That means more than half your submissions are getting caught.

And QuillBot's pricing doesn't help. The free tier gives you 125 words. That's not even enough for an introduction paragraph. Want unlimited? That's $19.95 a month. For a tool that fails detection over half the time.

Students are broke. We know because we were students too. Paying $20/month for a tool that works less than half the time is a bad deal by any measure. That's why thousands have switched to QuillBot alternatives that actually work.

SupWriter's Free Tier: What You Get

No gimmicks. No "enter your credit card for a free trial" nonsense. Here's exactly what SupWriter gives you for free:

• 300free words — enough to test a full paragraph or short essay section. More than double QuillBot's 125-word free limit.
• 99%+bypass rate across Turnitin, GPTZero, and Originality.ai. Same rate on free and paid plans. We don't nerf the free version.
• $0credit card required. Sign up with your email and start humanizing. If you want more words later, paid plans start at $9.99/month — half what QuillBot charges.

The free tier uses the same humanization engine as our paid plans. We don't downgrade quality to push upgrades. You get the full 99%+ bypass rate whether you're on the free plan or the Ultra plan.

QuillBot Free vs SupWriter Free: Honest Comparison

We're not going to pretend QuillBot is useless. It's a solid paraphrasing tool. But for AI humanization specifically, the free tiers aren't even close:

The numbers speak for themselves. QuillBot gives you fewer words, lower bypass rates, and charges nearly double if you upgrade.

One thing QuillBot does offer that SupWriter doesn't: a grammar checker and citation generator. If you need those, pair SupWriter with a free grammar tool like Grammarly's free tier. You'll still save money compared to QuillBot Premium.

Curious how Turnitin catches QuillBot paraphrasing? We did a deep dive with real test results. And if you want to see how QuillBot stacks up against other tools, check our QuillBot vs WriteHuman comparison.

Related Resources

• Best QuillBot Alternatives (2026) — Full ranked list for humanization
• Grammarly vs QuillBot — Head-to-head comparison
• QuillBot Review 2026 — Honest test results and bypass rates
• Can Turnitin Detect QuillBot? — Proof that Turnitin flags it
• Best Grammarly Alternative — If you also use Grammarly