How to Use the SynthID Detector: Step-by-Step Guide

By Alex | Last Updated: October 2026

Independent information site. Not affiliated with or endorsed by Google. The official detector is at synthid.com.

To check a file for SynthID, upload it at synthid.com, ask Gemini, or use the check built into Chrome. Each route answers one narrow question: is a SynthID watermark from a supported AI tool in this file? This guide walks through every route, how to read the answer, and what to do when a check doesn't work.

Before you start

Pick a supported file. The public site takes common image, video and audio formats (listed below), and Gemini checks one file at a time.
Have the right account. The public site asks you to sign in with a Google, OpenAI or Apple account. Gemini needs a personal Google account or a qualified Workspace account.
Use the original file if you can. Google says SynthID watermarks usually survive rescaling, recoloring and compression, but detection can fail after many alterations, and very small edits may not carry a detectable mark. A screenshot or a heavily recompressed copy gives the checker less to work with.
Know what you are asking. The detector does not decide whether something "looks" AI-made. It looks for a hidden mark that supported tools add when they create or edit a file.

Method 1: the SynthID Detector at synthid.com

Open synthid.com in your browser.
Sign in with a Google, OpenAI or Apple account.
Upload one image, video or audio file.
Read the result.

According to press reports at launch, supported formats are:

Media	Formats
Images	JPG, JPEG, PNG, BMP, WEBP, AVIF, HEIC, HEIF, TIFF, TIF, GIF
Video	MP4, MOV, WEBM
Audio	WAV, MP3, OGG, FLAC, AAC, M4A

The public site gives a simple answer. In Google's sample, a positive result says SynthID was detected, that the media was made or edited with Google AI, and that it may have been edited since. Early testers of the internal tool saw highlighted regions, but the public version does not show them. Each user gets roughly 10 checks a day, so see our limits and quota guide before you batch-test files. The exact buttons may change, so follow the on-screen prompts.

Method 2: ask Gemini

Google's help page for Gemini describes this route:

Go to gemini.google.com on your computer and sign in.
Click Add files and choose Upload Files, Photos, or Add from Drive. Drive uploads need Keep Activity turned on and Google Workspace connected to Gemini Apps.
Ask a plain question, such as whether the file was made or edited by Google AI.

Gemini accepts images, videos and audio, one file at a time, up to 100 MB. Videos must be under 90 seconds and audio under one hour. If the file carries Content Credentials, Gemini can also summarize its origin and edit history, which is a separate check from SynthID.

Method 3: Chrome, Search and Circle to Search

Google says SynthID checks are built into Gemini, Search and Chrome. Coverage of the I/O 2026 announcement describes a right-click option on images in desktop Chrome and a check in Circle to Search on Android. Those reports describe the features as being rolled out without a firm date, so what you see depends on your browser version and region.

How to read the result

Where	Result	What it means
Gemini	Watermark detected	All or part of the file was created or edited by Google AI models. For video, Gemini says which parts, which does not mean every frame in those parts carries the mark
Gemini	Not detected	Google AI did not create or edit the file, though another AI system could have
Gemini	Unclear	Often a very simple or abstract image, or an edit too small to carry a mark
synthid.com	Detected	A SynthID partner's AI tool made or edited the media, and it may have been edited since
synthid.com	Not detected	No supported SynthID mark was found. This is not proof the file is real

No result tells you which tool was used, who made the file, when, or how much of it is AI.

Troubleshooting

Problem	Likely cause	What to try
The upload fails	Unsupported format or file too large	Convert to a supported format. In Gemini, stay under 100 MB, 90 seconds of video, one hour of audio
Gemini says "unclear"	Very simple or abstract content, or a very small edit	Check the original full-quality file rather than a crop or copy
A screenshot gives a weak answer	Detection is weaker after many alterations	Crop tightly around the image, avoid collages, and find the original if possible
You expected a positive and got a clean result	The tool may not use SynthID, or the file was altered a lot	A clean result proves nothing. Use the checks in our alternatives guide
A real-looking photo comes back positive	AI may have edited part of it	A positive means made or edited. Ask the source about retouching or generative fill
You hit a limit	Daily quota reached	Wait for the reset. Gemini has its own limits (see our limits guide), and Google doesn't say whether the two share a quota
You can't sign in	Wrong account type	synthid.com accepts Google, OpenAI or Apple accounts. Gemini needs a personal or qualified Workspace account

What to do next

A SynthID check is one signal. If the file matters, also read how SynthID compares with C2PA and AI classifiers, run a reverse image search, and check who posted it first.