Calorie deficit calculator.
Find your maintenance calories, the daily deficit, and the exact target daily intake to hit your weekly weight-loss goal. Enter your details, pick a pace, and the result updates instantly - in pounds or kilograms.
Calculate your deficit
your numbers
Maintenance (TDEE)
0 kcal/day
Daily deficit
-0 kcal/day
Target daily calories
0 kcal/day
Estimates only, based on the Mifflin-St Jeor equation and the ~3,500 kcal/lb (7,700 kcal/kg) fat rule. Track your real weight trend for 2-3 weeks and adjust. Not medical advice.
the short answer
A calorie deficit calculator finds your target intake as maintenance calories (TDEE) minus a daily deficit. TDEE = Mifflin-St Jeor BMR x an activity factor. The deficit = your weekly loss rate x 3,500 kcal/lb (or 7,700 kcal/kg), divided by 7. So a 1 lb/week goal means a ~500 kcal daily deficit and a target of TDEE - 500.
What a calorie deficit is and how it's calculated.
A calorie deficit is eating fewer calories than your body burns in a day, which forces it to use stored energy and drives weight loss. To turn that into a number you need two things: your maintenance calories and the deficit you want to run.
First, maintenance - your TDEE (Total Daily Energy Expenditure). This calculator uses the Mifflin-St Jeor equation for BMR: BMR = 10 x weight(kg) + 6.25 x height(cm) - 5 x age + 5 for men, and - 161 instead of + 5 for women. BMR is then multiplied by an activity factor (1.2 sedentary up to 1.9 athlete) to get TDEE. Imperial inputs are converted to metric internally before the math runs.
Second, the deficit. One pound of body fat stores roughly 3,500 kcal (one kilogram ~ 7,700 kcal). So your daily deficit = weekly loss rate x 3,500 / 7 (or x 7,700 / 7 for kg), and your target daily intake = TDEE - daily deficit. A 0.5 lb/week pace is about a 250 kcal deficit; 1 lb/week is about 500. These are population-average estimates, so verify against real weight-trend data over a few weeks.
How coaches use a calorie deficit calculator.
Online fitness and nutrition coaches use a calculator like this to set a realistic starting target and an honest timeline before a client's first week. It turns vague advice like "eat less" into a specific daily number the client can actually follow - then the real work is reviewing weekly check-in data and adjusting the target as the trend reveals each client's true maintenance.
It also doubles as a shareable lead magnet: send a prospect the link, let them see their numbers, and start the nutrition conversation with something concrete. For the deeper method - estimating maintenance and splitting it into protein, carbs, and fat - see our guide on how to calculate TDEE and macros for clients, and the broader playbook in how to do nutrition coaching online.
Set targets like this for every client.
A calculator gives one person one number. Coachway lets coaches set a calorie and macro target for each client once, deliver it in a branded client app, and track progress against it automatically through weekly check-ins - so you spend your time coaching, not recalculating. Explore the meal planner or compare the best online nutrition coaching platforms.
Start with CoachwayMore free calculators: TDEE calculator and macro calculator.
Calorie deficit calculator FAQ.
How does a calorie deficit calculator work?
A calorie deficit calculator first estimates your maintenance calories (TDEE) using the Mifflin-St Jeor equation multiplied by an activity factor. It then subtracts a daily deficit sized to your chosen weekly weight-loss rate - about 3,500 kcal per pound (7,700 kcal per kilogram) of fat, divided across seven days - to give a target daily calorie intake.
How big should my calorie deficit be to lose weight?
A common, sustainable target is a 500 kcal daily deficit, which projects to roughly one pound (about 0.45 kg) of weight loss per week. Faster rates like 0.75 to 1 lb per week need a larger deficit and are harder to hold. The right size depends on your maintenance calories, body size, training, and how aggressive you want the timeline to be.
How many calories should I eat to lose 1 lb a week?
To lose about one pound a week you need roughly a 500 kcal daily deficit, since one pound of fat stores about 3,500 kcal. Enter your details above to get your maintenance calories, then subtract 500 - the calculator does this for you and shows the target daily intake plus the projected weekly loss for your chosen rate.
Is the calorie deficit calculator accurate?
It gives a solid, science-based estimate, but every formula is an approximation. The Mifflin-St Jeor equation and the 3,500-kcal-per-pound rule are population averages, so your real maintenance can vary with muscle mass, metabolism, and how much you actually move. Treat the result as a starting point, then adjust based on two to three weeks of real weight trend data.
Can I lose weight too fast with a large calorie deficit?
Yes. Very aggressive deficits can cost you muscle, energy, sleep, and adherence, and they are hard to sustain. Most coaches keep weekly loss to roughly 0.5 to 1 percent of body weight and pair the deficit with adequate protein and resistance training. Slower, steady loss usually holds better than a crash diet that rebounds.
How do coaches use a calorie deficit calculator with clients?
Coaches use it to set a realistic starting target intake and a believable timeline, then review weekly check-in data and adjust. It turns "eat less" into a specific number a client can act on. On a coaching platform you set each client a calorie and macro target once, and their app tracks progress against it automatically.
This calculator provides general estimates for education, not medical, dietary, or clinical advice. Calorie needs vary with body composition, health conditions, and activity, and the formulas used are population averages. Consult a qualified professional before making significant changes to your diet, especially if you have a medical condition.
More free calculators
See all free tools ->TDEE Calculator
Total daily energy expenditure, plus cut, maintain and bulk targets.
Open calculator ->Maintenance Calorie Calculator
The calories that keep your weight steady - your starting line.
Open calculator ->BMR Calculator
Basal metabolic rate from the Mifflin-St Jeor equation.
Open calculator ->Macro Calculator
Protein, carb and fat targets in grams for your goal.
Open calculator ->Protein Calculator
How much protein to eat per day, by bodyweight and goal.
Open calculator ->Reverse Diet Calculator
A week-by-week schedule from your cut back up to maintenance.
Open calculator ->See what Coachway can do for your coaching business
Coachway was built after working with 150+ coaches who all had the same frustrations - slow platforms, clunky workflows, wasted hours. Book a demo and see what we fixed. 15 minutes, and you'll know if it's the right fit.
