A little more understanding. Every day.
A calorie target.
That learns you.
Photograph your meals. Follow your weight trend. Marble uses what happens over time to refine the calorie target you started with.
Room for the rest of your day
An illustrative day in Marble
The scale
One morning is a dot.
The trend tells the story.
Switch views to see the same 28 weigh-ins with a little perspective.
The correction
A starting guess.
Then, a better fit.
Move through an example fortnight. See how the target responds when the measured trend differs from the plan.
- Planned
- −1.1 lb / wk
- Measured
- —
- Weigh-ins
- 1
Day one. The target is arithmetic, and arithmetic can be wrong.
It moves half the gap, never more than 250 calories at once, then waits another fortnight before it touches the number again.
The app
Your day, in perspective.
A place for your meals, your longer view, and your questions. Explore three views from the app.
Illustrative product views
What's left, and what you ate. One timescale, no streak to protect.
Where the number starts
You can see where
your number comes from.
What it asks of you
Less setup.
More getting on with it.
- No account
- No email
- No permissions on first launch
- Weigh-ins never leave your phone
- No streaks
- No cap on logging, ever
What it costs
The essentials are free.
Go a little further with Plus.
Two models read plates for Marble, both made by Anthropic. Free uses Claude Haiku; Plus uses Claude Sonnet for meal estimates and includes the coach. Your first two weeks are on Plus, with no card.
Free
$0, for good
- Three plates a day read by Claude Haiku — a photo, or a description
- Typing a meal in, barcodes and repeats: unlimited
- Weigh-ins, your trend, and every correction
Your first two weeks, on us
Plus
$4.99 a month
- Every plate read by Claude Sonnet, no daily limit
- The coach — real answers about your week, from your own record
- Corrections — tell it what it got wrong and the numbers recompute
Questions
The ones worth answering honestly.
How accurate is a photo, really?
A photo gives an estimate, and portions or hidden ingredients can be hard to judge. You can edit the numbers. Consistent logging gives Marble more useful context for adjusting your target, but it does not make individual meal estimates exact.
Do I have to weigh myself every day?
It's the thing that makes the rest work, and it takes ten seconds. Daily is also less stressful than weekly: when every reading is one dot in a line, no single morning is a verdict.
What does it cost?
Your first two weeks are on Plus, with no card: every plate read by Claude Sonnet, and the coach. After that Marble stays free — three plates a day read by Claude Haiku, and typing a meal in, scanning a barcode or logging a past meal again are always unlimited. Plus is $4.99 a month and keeps Sonnet on every plate, the coach, and corrections. Sonnet is the better reader of the two, mostly at judging portions; Haiku is fast and fine for most meals.
Where does my data go?
Your weigh-ins never leave your phone; the trend and every correction are computed on the device. Meal photos, descriptions and coach messages are sent for AI processing. Barcode lookups go to Open Food Facts, and a random app identifier is used to manage AI usage. Detail on the privacy page.
Is this a good idea if I've struggled with food?
Talk to a doctor or a dietitian first. Marble hides single readings, refuses to celebrate streaks, and tells you when a scary morning is meaningless — but it is still an app that counts, and counting isn't right for everyone.
Stop trusting the number.
Start measuring it.
Free, no account, and it will tell you when it's wrong.