A weight tracker that measures your metabolism instead of guessing it.
Free, no sign-up, and nothing user-identifying leaves your browser.
One exception, named plainly. Searching for a food sends an anonymous query to the food database. It carries no identity with it, and nothing else leaves.
Check it yourselfEvery calorie app tells you what your body burns. Almost all of them are guessing, using a population formula from 1990 that can be off by 500 calories a day for any individual. TrueBurn starts with that same formula, then throws it away. After two weeks of logging it measures what you actually burn, from what you actually ate and what your weight actually did. It shows you the arithmetic. It runs entirely in your browser, with no account and nothing sent anywhere. And when the numbers cannot tell you something, it says so instead of making it up.
Ask three apps what you burn in a day and you get three confident numbers, all produced the same way.
That formula is a population average published in 1990. It describes people your size, not you, and the activity multiplier layered on top of it is a guess you made about yourself.
What you ate across a window, plus what your weight trend actually did, implies what you must have burned. No activity band, no multiplier, no dropdown.
Three pounds of fat is more than ten thousand surplus calories, which did not happen overnight. Each gram of stored carbohydrate holds roughly three grams of water, and that is what the scale is reacting to. Both lines are shown together so the claim is checkable rather than reassuring.
Every figure in the app carries that same panel. If I cannot explain how I got a number, I do not display it.
It needs about two weeks of complete days before it says anything, and it inherits whatever bias is in your food log. A stable 15% under-log is fine, because it cancels. What actually breaks the math is drift.
The formula's own published error for one individual is 15 to 23%. Drawn to scale against a 2,408 estimate, that is the band below. The measured number lands inside it, which is exactly why a small gap between the two means very little on its own.
No error bars anywhere on this site, and no precision claim. Displayed uncertainty would cover day-to-day weight noise only, while the larger error is one-directional bias in your own logging that no interval covers.
I am not the first to measure expenditure from intake and weight trend, and saying otherwise would be the exact kind of claim this project exists to refuse.
The person who will not pay $70+ a year, or who does not want their weight history sitting in someone else's database, currently has no option in this category at all. That person is who TrueBurn is for.
Who this is for, and who it is notThe free mode has no sign-up, no server, and no telemetry attached to you. Your weight, your food, your history: all of it lives in your browser and nothing user-identifying ever leaves the device. The only network call is an anonymous food-database lookup.
Most trackers use your expenditure to set a calorie target, so the number itself only has to be close enough to aim with. Here the number is what you came for, so it has to be right, and it has to tell you when it is not.
One example, already built. When your weight holds steady, the number is coming entirely from your food log and nothing else, so the app stops calling it a measurement and tells you that instead.
Each figure the app produces has a "show the math" expander: the inputs, the arithmetic, and the constant. If I cannot explain how I got a number, I do not display it.
The Metabolism screen compares your measured burn to the formula estimate and then states the formula's own 15 to 23% error in your calories, so you can see for yourself that a small gap means nothing.
No leaderboards, no friend feeds, no ranking, no "you are in the top 20% of users". Progress is always you against your own last month. This is stated as a value during onboarding rather than being quietly absent.
Repeat logging is slow, there are no recents or saved meals yet, and the achievement screen is hidden while it is rebuilt. You would find that out in a week anyway, so you may as well know now. What is next, and what is never being built
Statistically it is the eating, and that is not an accusation. Under-reporting is unconscious and close to universal. But you do not have to settle this with population statistics, because your own numbers can answer it directly.
On the metabolism half of the question: between two people of the same size, sex and body composition, the honest spread is a few hundred calories a day, not the thousand people imagine. Most people who feel like an outlier are not one.
After enough complete days the app puts your measured burn next to what the formula predicts for a body your size and names the gap in calories. If you genuinely sit below prediction, it says so plainly. If you do not, the same measurement points you at the deficit arithmetic instead.
A calculator predicts. This measures.
A TDEE calculator takes your height, weight, age, sex and an activity band you picked for yourself, then returns what someone with those inputs tends to burn. That band is a guess you made about yourself, and it is usually the largest single error in the answer.
TrueBurn runs it the other way round. What you ate across a window, plus what your weight trend actually did, implies what you must have burned:
The limits are real and worth saying in the same breath. It needs about two weeks of complete days before it says anything, and it inherits whatever bias is in your food log.
Yes. That is worth conceding first, because it is true.
Average under-reporting runs around 12 to 16 percent, and higher while someone is actively dieting. If you log 15 percent low every day, your measured expenditure reads about 15 percent low.
It is still useful, because the target it produces is expressed in the same units you log in. Log 15 percent low, get a target 15 percent low, and you still land at the intended rate of loss.
What breaks it is inconsistency, not inaccuracy. Getting more careful halfway through a window moves the number for no physiological reason. Log the same way on good days and bad days, and distrust any reading taken across a stretch where your habits changed.
Nothing yet. There is no revenue, no advertising and no data deal.
There is also nothing here to sell. Your logs never leave the device, so there is no dataset to license. You can check that yourself: turn the network off after the first load and the app keeps working.
A paid sync tier is planned, for people who want their history on more than one device. That is a different product with real server costs. If any of the above ever changes, it changes in the changelog and on this page before it ships, not quietly.
This is a permanent commitment, not a launch promise. Private local-only mode stays free. Paid tiers, when they exist, will be for people who want their data synced across devices, and that is a genuinely different product with genuinely different costs. Nobody will ever have to hand over their weight history to keep using what they already have.
It does not model your condition, and it does not need to, because it measures the outcome.
Whatever a condition or a medication is doing to what you burn is already inside your weight trend and your intake, so it lands in the measured number without anyone having to name it.
What it cannot do: tell you why the number is what it is, identify a condition, or stand in for your clinician. It is not medical advice.
One thing worth doing anyway. If your measured number moves sharply and nothing about your eating explains it, that is worth mentioning at your next appointment.
For about the first two weeks it shows the formula estimate and calls it an estimate, with a countdown of the complete days still needed. After that it shows you what you actually burn, and the arithmetic that produced it.
Free. Private. No sign-up.