SynthID Detector Limits and Daily Quota
By Alex | Last Updated: October 2026
Independent information site. Not affiliated with or endorsed by Google. The official detector is at synthid.com.
The public SynthID Detector caps each signed-in user at roughly 10 image, video and audio checks per day, according to a statement Google gave Ars Technica. Gemini publishes its own, different limits and file caps. This page lists every limit we could confirm, says plainly which details are still unknown, and explains what to do when you hit the cap.
Limits at a glance
| Where | Limit | Source |
|---|---|---|
| synthid.com | About 10 checks per day per user, counted across images, video and audio. Sign-in with a Google, OpenAI or Apple account is required | Google, as reported by Ars Technica and TBreak |
| Gemini: files | One file at a time, up to 100 MB. Video under 90 seconds, audio under one hour | Google's Gemini help page |
| Gemini: usage | In a rolling 24-hour window, about 10 image checks, 10 video checks (up to 5 minutes in total) and 10 audio checks (up to 3 hours in total). Gemini tells you when you reach a limit | Google's Gemini help page |
| Language | English only at launch | |
| Text | The public site has no text check | Press reports |
Still unknown: when the synthid.com quota resets, whether failed or repeated uploads count against it, and whether it differs by media type. The Google material we read does not say, so any page claiming exact answers is guessing.
Why there is a limit
Google's engineers told Ars Technica that the cap exists to stop people from using the detector to develop ways to strip SynthID. Our reading of that reasoning: a yes-or-no answer on every upload is useful feedback to someone trying to defeat a watermark, so limiting how many files one person can test makes that harder. TBreak noted that the quota is described as "approximately" 10, which may mean the system can cut you off earlier if you keep uploading near-identical files. That last point is TBreak's reading, not something Google has confirmed.
How to make your checks count
Google has not said how a check is counted, so treat each upload as one of your 10.
- Check the files that matter most first.
- Don't test several edited versions of the same file. Find the original instead.
- Screen with free checks that don't use the quota, such as a reverse image search or a Content Credentials viewer.
- Keep a simple log of what you checked and the result so you never repeat a check.
What to do when you hit the cap
- Wait for the reset. For Gemini, the window is a rolling 24 hours. Google has not said when the synthid.com quota resets.
- Try Gemini. Gemini publishes its own limits, which differ from the public site's. Google doesn't say whether the two share a pool, so you may still be able to check there.
- Use other checks. A reverse image search and a Content Credentials viewer don't use the SynthID quota.
- For a suspected OpenAI image, OpenAI's own verification page checks for OpenAI's marks.
- If it is urgent and important, treat the file as unverified rather than guessing from a partial check.
Other limits that are not about quota
- Sign-in is required. There is no anonymous use.
- English only, with no other languages announced.
- Only SynthID partners. The detector recognizes Google, OpenAI, NVIDIA and Kakao, with Apple announced. Everything else can come back clean. See which AI tools use SynthID.
- A plain yes or no. The public site doesn't highlight where in the file the mark sits.
- Made or edited. A positive result doesn't say whether AI made the whole file or only changed part of it.
- No text. Gemini text is watermarked, but the public detector doesn't check text.
Questions people ask
How many checks can I do per day?
About 10 on synthid.com, across images, video and audio combined, according to Google as reported by Ars Technica.
Does the limit reset at midnight?
Google hasn't said for synthid.com. Gemini's help page describes a rolling 24-hour window.
Can I pay for more checks?
None of the sources we read mention a way to raise the limit.
Is the limit there to protect users?
The reason reported from Google's engineers is preventing the development of watermark-removal tools. We found no other reason stated.