Calorie deficit calculator
Daily deficit, intake, and weekly loss from your maintenance calories and a weekly rate.
Free. No account required.
How the calculation works
Weekly loss is body weight times the weekly percent. Daily deficit is that loss in pounds times 3,500, divided by 7. Daily intake is maintenance minus the deficit. Pounds and kilograms use one conversion, 453.59237 grams per pound, so switching units does not change the deficit. The numbers on screen are whole cals.
If you type a maintenance number, that number is used. The estimate is Mifflin-St Jeor times the same activity categories as the TDEE calculator (1.2, 1.375, 1.55, 1.725, 1.9). It has one constant for male and one for female, and it is not a measured burn. 3,500 cals per pound is an approximation: people often lose less than it predicts, and the loss is not all fat. The cutting calculator uses 7,700 cals per kilogram, about 3,493 cals per pound, so the two pages can differ by a few calories.
A worked example
140 lb, 2,000 cals maintenance, 0.5% per week: 0.7 lb (0.32 kg) a week, a 350 cals deficit, and 1,650 cals a day. The same weight in kilograms gives the same deficit.
Sources checked November 7, 2026: Mifflin et al., 1990; Frankenfield, Roth-Yousey, and Compher, 2005; Hall and colleagues, Lancet, 2011; Thomas et al., on the 3,500 cals rule, 2013; ISSN position stand, 2017; ACSM consensus statement, 2024.
Common questions
Is 500 calories the right deficit?
Not by default. On this shortcut, 500 cals a day is about a pound a week, and a pound is a different percent of body weight at 140 lb than at 240 lb.
Will I lose exactly this much?
Often it comes in slower. Water moves the scale, and a smaller body burns less. Give it two or three weeks of trend weight before you change the target.
What do the warnings mean?
Above 1% of body weight a week, or more than about 25% below maintenance, is faster than most lifting cuts. Under 1,200 cals, or 1,500 cals for the male estimate, is the same caution line as the TDEE calculator. The math still shows. It is not a suggestion to eat that little.