Almost every question about losing fat is an arithmetic question that nobody shows the working for. How many calories should I eat? How long will twenty pounds take? Is tahini good for weight loss? What does my waist measurement actually say? These free tools answer one of those questions each, from your own numbers, in a few seconds — and every one of them shows where its numbers came from, and how far off they can be. Nothing to sign up for, nothing to install, and nothing you type leaves your phone.
Fat-Loss Calculators
Your body and your goal in, the honest number out: calories, the date, the pace that is safe.
Body Measurements
A tape, a scale and your height in — what they mean, and how sure anybody can be.
Food & Fuel
A food, a drink or a day’s eating in: what it costs in calories, and what it gives back.
Where the numbers come from
Every equation, cut-off and food value here is quoted from whoever published it — the National Academies, the CDC, the NIH, the World Health Organization, the USDA’s own food database, or the paper the formula was first printed in — with the date we last checked it printed next to the answer. Nothing is invented, nothing is estimated to look precise, and nothing is averaged out of thin air.
Where the experts disagree, you get to see it
Fat loss is full of rules that contradict each other, and most calculators quietly pick one. The calorie equation every website uses and the one the US government published in 2023 give different answers. The famous “3,500 calories is a pound” rule and the model the NIH built to replace it predict different dates. Two official bodies recommend different amounts of water. Our tools show both sides and say who said what, because an average of two methods is a number nobody published.
Every estimate comes with its error
A tape-measure body-fat percentage is an estimate that can be three or four points out. A calorie equation is close for most people and off by ten percent or more for some. A tool that prints one confident number is hiding that, so ours print the range — which is also the honest reason to weigh yourself for a few weeks and adjust, rather than trust any calculator for good.
What these tools will not do
They will not plan a loss faster than about two pounds a week, or a day of eating below 1,200 calories for a woman or 1,500 for a man — the lines public-health bodies draw for dieting without a doctor. They will not plan towards a weight that is under the healthy range for your height. They are not for children, or during pregnancy or breastfeeding, or for anyone with a history of an eating disorder; if that is you, the right person to plan with is a doctor or a registered dietitian. And nothing here diagnoses anything or doses any medicine, including the weight-loss injections.
Share an answer, or keep it
Every result has its own link. Copy link saves exactly what you entered, so you can come back to the same numbers next week, or send them to someone you are doing this with.
Put a tool on your own site
Every tool has an Embed button. It gives you a short piece of code to paste into a page, a forum post or a club’s resources page. The tool works there exactly as it does here, free, with a credit line linking back.
More from the site
The tools do the arithmetic. For the food, the diets and the everyday habits behind it, start with the latest from BurnMyFatFast.