Free calorie & macro calculator
Know exactly how much to eat.
Your daily calories and macros, worked out the way a sports scientist would: it picks the most accurate formula your data supports, refuses to hand you a dangerous number, and shows every step of the math. Built with AI deep-research across the published literature — the kind of synthesis that used to need a dietitian and a stack of journals.
3 steps · ~2 min · nothing stored
Not medical advice. Check with a dietitian before making big changes to your diet.
Sample plan
computed live
2,293
kcal / day · 486 kcal below maintenance
29-year-old male, 178 cm, 82 kg, moderately active, moderate fat loss. BMR 1,793 kcal → TDEE 2,779 kcal. These numbers come from the same engine you're about to use.
Under the hood
What happens when you hit calculate.
Four stages, each backed by published research. No black box — your results page shows which path your numbers took.
- 01BMR
Resting burn
What your body burns doing nothing — keeping your heart beating, brain running, muscles ticking over. This is where the tiered formulas kick in.
- 02TDEE
Daily burn
Your resting burn multiplied by how active your life actually is, from desk job (×1.2) to physical work plus hard training (×1.9).
- 03TARGET
Goal adjustment
Cutting? A deficit sized to your body fat, so lean people aren't pushed too hard. Building? A surplus sized to your training age, so beginners get more.
- 04PROTEIN · CARBS · FAT
Macro split
Protein set per kg of body weight for your goal, fat held above a healthy floor, carbs fill the rest to fuel training.
The clever bit
Three formulas. It picks the best one you qualify for.
Most calculators run one equation for everyone. But the research is clear: the more you know about your body composition, the more accurate the math can get. Tell it more, get a better number — and it always tells you which formula it used.
Tier 01
Cunningham
needs body-fat % + training history
The researcher's choice for trained athletes. Works from lean body mass, so muscle actually counts.
Tier 02
Katch-McArdle
needs body-fat %
Lean-mass based without the training requirement. A rough body-fat estimate is fine — precision matters less than you'd think.
Tier 03
Mifflin-St Jeor
needs just the basics
The gold-standard general formula — the one clinicians reach for. Small age and ancestry adjustments are applied only where research supports them, and always flagged.
Learn
Every number here has a paper behind it.
Wondering why it picks one formula over another, or why the scale stalls in a deficit that should be working? We wrote it up. 11 plain-English explainers, every claim linked to the study it came from.
Browse the Learn hubGuardrails
It will refuse to give you a reckless number.
Aggressive targets are easy to generate and miserable to live with. The engine caps what it will recommend and warns you when your inputs push against the limits.
- Calorie floorsNever below 1,200 kcal (women) or 1,500 kcal (men)
- Deficit capsMaximum deficit scales with your body-fat percentage — leaner means gentler
- Refeed flagsDeficits past 20% trigger a periodic refeed recommendation
- Macro minimumsFat never drops below 0.6 g/kg; carbs never below 50 g
- Transparent adjustmentsAny population-level tweak is flagged in your results, never silent
Your data
Yours. Not ours. Not anyone's.
Your body, your numbers. Everything is computed inside your browser — there is no account to create, no server receiving your inputs, and no database holding them. Close the tab and it's gone. Health information belongs to the person it describes.
- No account
- No server
- No database
- No tracking scripts
Free · no account · runs in your browser
Two minutes of honest inputs. A plan that shows its working.
Start the calculatorNot medical advice. Check with a dietitian before making big changes to your diet.