Calorie deficit calculator
Most people lose about 0.5 kg (1 lb) a week by eating around 500–550 calories a day less than they burn. Enter your details to see your maintenance calories and a daily target for each rate of weight loss.
How your calories are worked out
First, your resting burn (BMR) is estimated with the Mifflin-St Jeor equation, from your sex, age, height and weight. That’s multiplied by your daily activity to give your maintenance before exercise: the calories that keep your weight steady on a day you don’t train. If you pick a body type, maintenance moves 5% down (you gain weight easily) or up (you find it hard to gain), the same as the Get Gains app.
BMR (men) = 10 × kg + 6.25 × cm − 5 × age + 5BMR (women) = 10 × kg + 6.25 × cm − 5 × age − 161Maintenance = BMR × 1.2 (desk job) to 1.7 (heavy manual work)Body type (optional): × 0.95 if you gain easily, × 1.05 if you find it hardDaily deficit = kg a week × 7,700 ÷ 7 Sources: Mifflin et al. (1990), A new predictive equation for resting energy expenditure in healthy individuals; Hall et al. (2011), Quantification of the effect of energy imbalance on bodyweight
The 7,700 kcal per kg rule is a starting estimate. Weight loss usually slows over the months as your body gets smaller and adapts, so expect to re-check your numbers as you go.
Why workouts aren’t included
The activity levels here describe your job and daily life only. Workouts vary too much from day to day to average into one number, so instead you add what each session burns on the days you train. This is how Get Gains works too: a base target, plus the calories from each logged workout.
Should you eat back exercise calories? If your target already assumes no exercise, eating back some or all of a workout’s calories keeps your deficit where you planned it and helps you train well. Fitness trackers often overestimate burn, so many people eat back about half to start.
Safe minimums
The calculator flags any target under 1,200 kcal a day for women or 1,500 for men. Going lower makes it hard to get enough protein, vitamins and minerals, and is difficult to keep up. If a target is flagged, choose a slower rate or speak to your GP or a dietitian first.
If you’re worried about your eating, your weight, or how much you exercise, Beat, the UK eating disorder charity, can help: call 0808 801 0677 or visit beateatingdisorders.org.uk.
Common questions
Why has my weight loss stalled?
Day-to-day weight swings with water, salt and food in your gut, so judge trends over two to three weeks. If the trend is flat for that long, re-run the calculator with your new weight, check your logging, then reduce by 100–200 kcal if needed.
Can I eat more at the weekend?
Yes. What matters is your average over the week. Eating a little less on weekdays to have more at the weekend works, as long as the weekly total stays on target.
What’s a diet break?
A planned week or two eating at maintenance during a long diet. It can make a diet easier to stick to; it won’t undo your progress.
Let the numbers keep up with you
Your calorie needs change as your weight does. Get Gains adjusts your target as it learns your real burn from your logs, adds workout calories automatically, and pairs it with a protein target to keep your muscle while you lose fat. More free calculators.