AI body fat calculator
See whether your body is changing.
Get a private AI body-fat baseline now, repeat the same photo monthly, and see the direction your scale can miss. No account or card required.
1
complete baseline free
0
photos stored by FormCheck
4
weeks between comparisons
How it works
A free baseline now. A useful trend over time.
01
Capture consistently
Use one front-facing, full-body photo in neutral lighting and a relaxed pose.
02
Review the range
The model checks photo quality first, then returns a range and confidence—not false precision.
03
Repeat in four weeks
Recreate the setup and compare your private numeric results to see the direction.
Reliable photo checklist
Make the next photo comparable.
- — Head-to-ankles framing
- — Arms relaxed at your sides
- — Even front lighting
- — Fitted athletic clothing
- — Camera level at waist height
- — No flexing or post-workout pump
Photo examples
What a usable check-in photo looks like.
Good · full bodyHead to ankles visible, fitted clothing, neutral front pose.
Photo: SoyBreno on Unsplash
Good · relaxed stanceArms at your sides, even lighting, consistent distance.
Photo: Shoham Avisrur on Unsplash
Avoid · croppedTorso-only crops hide proportions and often get rejected.
Photo: UnsplashBuilt for consistency
A useful trend beats a confident guess.
Daily weight moves with water, food, and timing. FormCheck helps you reproduce the same photo setup, records an honest estimate range, and compares like with like.
Compare body-fat measurement methods →Example result
18%
Estimated range 16–21% · medium confidence
Your actual result includes capture feedback and a repeatable next check-in date.
The progress problem
You do not need another perfect number. You need to know if the work is working.
Your first successful estimate is free. Start a progress membership only when you want to compare it with what happens next.
Try before you decide
Start with your real result.
No pricing quiz and no account wall. Create the baseline first; then FormCheck shows exactly what a future comparison will unlock.
Privacy by design
Your photo is input, not a permanent record.
FormCheck removes image metadata, sends the photo securely for the analysis request, and does not store the source image. Only your numeric result and analysis details are saved to your private account.
Read the privacy details →Body composition guides
Understand your body fat percentage.
Charts, formulas, and evidence-based guides to interpret your estimate and track progress over time.
Questions, answered honestly.
Is this a medical body-fat measurement?
No. It is a directional visual estimate. It should not replace DEXA, clinical advice, or decisions about your health.
What kind of photo works best?
Use a recent front view with your full body visible from head to ankles, arms relaxed, fitted clothing, a neutral pose, and even front lighting.
Can I use a smartphone photo?
Yes. Keep the phone level at about waist height, avoid wide-angle distortion, and stand far enough away to include your full body.
How do lighting and clothing affect the result?
Hard shadows can exaggerate definition and loose clothing can hide body shape. Even lighting and fitted athletic clothing make repeat comparisons more useful.
How accurate is the estimate?
Photo-based estimates have meaningful uncertainty and vary with pose, lighting, clothing, camera angle, and individual body-fat distribution. FormCheck reports a range and confidence instead of claiming clinical precision. Read our guide on AI body fat accuracy for a deeper explanation.
Are my photos stored?
FormCheck processes photos in memory for the request and does not save the source images. Your numeric result is saved to your private account.
What does the free estimate include?
Your first successful estimate includes a body-fat range, confidence, general model observations, capture feedback, and a suggested next check-in date. No card or account is required.
How quickly will I get a result?
Most usable photos are analyzed in seconds. Large uploads or a slow connection can take longer.
How often should I check in?
Every four weeks is usually enough to see a useful direction. Repeat the same lighting, clothing, pose, distance, and time of day. See our blog post on how often to measure body fat for the reasoning behind that interval.
Can I compare this with DEXA, scales, or tape methods?
Yes, but treat each method as its own series. A DEXA scan, smart scale, tape formula, and visual model can use different assumptions, so compare trends within the same method. Our comparison of body fat measurement methods explains the tradeoffs.
Does it work for every body type?
The model is designed for varied adult body types, but individual fat distribution and photo conditions still affect uncertainty. A low-confidence range should be treated cautiously.
Do I need an account?
Not for your first estimate—it runs without sign-in. You can sign in with Google afterward to keep the numeric baseline for free. A progress membership unlocks future check-ins, private comparisons, and your trend.
How often can members check in?
FormCheck is built around one comparable photo about every four weeks. Membership includes a fair-use allowance for retakes and occasional extra checks, but consistency—not scan volume—is what makes the trend useful.