Calorie deficit calculator
Estimate your maintenance calories and a daily budget for losing, holding, or gaining weight. The same math Tek uses to set your budget, free and in your browser.
How the numbers are worked out
The calculator estimates your resting burn with the Mifflin-St Jeor equation, the same formula most clinical calculators rely on. It then multiplies that by an activity factor, from 1.2 for a mostly seated day up to 1.55 for a consistently active one, to reach your maintenance calories.
To create a deficit, it subtracts the energy implied by your chosen pace. Because roughly 7,700 calories maps to about one kilogram of body mass, aiming to lose half a kilogram a week works out to around 550 fewer calories a day. Larger cuts lose faster on paper but are harder to sustain, so the budget is never set below 1,500 calories.
Macros follow a simple, protein-forward split: protein near 1.9 grams per kilogram of bodyweight, fat at a quarter of your calories, and carbohydrates filling whatever remains.
Treat the result as a starting point. Log your meals for two to three weeks, watch the weight trend rather than any single morning, and adjust once if the trend is not moving as expected. For the full reasoning, readhow many calories to lose weight.
Questions, answered
How does this calculator work?
It estimates your resting burn with the Mifflin-St Jeor equation, multiplies by an activity factor to get your maintenance calories (TDEE), then subtracts the deficit implied by your chosen weekly pace. Around 7,700 calories maps to roughly one kilogram of body mass.
Why is my budget held at 1,500 calories?
Very low daily budgets are hard to sustain and easy to abandon. When the math would drop below 1,500 calories, the calculator holds there. If you want to lose faster, add movement rather than cutting food further, and talk to a professional before going lower.
How accurate is the result?
It is a starting estimate, not a measurement. Equations predict energy use well on average but vary by person. Track your intake against your weight trend over two to three weeks, then adjust your budget if the trend is not moving as expected.
Should I eat back exercise calories?
Generally no. Exercise-calorie estimates run high, and eating them back can erase your deficit. Pick the activity level that matches a normal week and keep your budget steady instead of earning and spending extra calories per workout.