Calorie deficit calculator
A calorie deficit means eating a little less than you burn. This calculator estimates your daily target for the pace you choose, and the month you could reach the weight you're aiming for.
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Torn between two? Pick the lower one.
Your pace
We start from what you burn in a day (Mifflin-St Jeor × your activity), then take away about 7,700 kcal per kilo to lose, spread over the weeks at the pace you chose. The date is a range: from the classic calculation, more optimistic, to a projection that accounts for what you burn dropping as you lose weight. The pace is capped at 1% of your weight per week, the deficit at 1,000 kcal per day.
Enter your age (18 to 80), your height and your weight in step 1: your plan appears right away.
Enter your goal weight in step 3: your plan appears right away.
Your goal weight needs to be lower than your current weight. To maintain your weight or build muscle, see “Calories per day” or “Protein and macros.”
This goal weight corresponds to a BMI under 18.5. Talk to a doctor before you start.
Your pace is brought down to 1% of your weight per week, the maximum used here.
The deficit is capped at 1,000 kcal per day.
We don't go below kcal per day, so your actual pace is slower.
With this fixed target, what you burn would end up matching what you eat before you reach your goal weight. Recalculate your target every few kilos (5 to 10 lb) to keep moving forward.
What you burn is already close to the kcal minimum: a deficit isn't possible here. Moving a little more is the simplest option.
What you eat, compared to what you burn.
That's about kcal per meal over 4 meals, snacks included.
Projection at the pace you chose.
The curve slows down: what you burn drops as you lose weight. The dotted line follows the rule of 7,700 kcal per kilo, which is more optimistic. An estimate, to adjust based on your weigh-ins.
Tap “?” to understand each number.
The difference between your current weight and your goal weight.
kcal
About 7,700 kcal per kilo of fat, according to the common rule. An approximation that slightly overestimates the loss over time.
Body mass index: your weight divided by your height squared.
Your BMI once you reach your goal weight. Between 18.5 and 25 is considered a normal weight.
Estimates for healthy adults aged 18 to 80, not medical advice. Pregnant, breastfeeding, or being treated for an illness or an eating disorder? Ask a doctor or a dietitian before changing your diet.
per week kcal less per daycapped at , 1% of your weightslowed to so you stay above kcal wk to wkabout monthsabout to monthslonger than planned, recalculate your target along the wayGoal month · Goal month · not set yetafter Target kcal, deficit kcal, out of kcal burnedUnavailableFrom today to around Projection unavailableThe common rule counts about 7,700 kcal per kilo lost (roughly 3,500 kcal per pound): 550 kcal less per day comes to about 0.5 kg (1.1 lb) a week. Example: a maintenance of 2,720 kcal, going from 80 to 72 kg (176 to 159 lb) at 0.5 kg a week, means about 2,170 kcal per day for at least 16 weeks, a little longer in practice, because what you burn drops with your weight.
The most common recommendation is 0.5 to 1% of body weight per week. The calculator caps the pace at 1% of your weight, the deficit at 1,000 kcal per day, and never goes below 1,200 kcal for a woman or 1,500 kcal for a man.
The scale often drops fast at first, partly because of water, then slows down: a lighter body burns less. That's why the date is given as a range, from the classic calculation to a projection that accounts for this slowdown: a ballpark figure, to the nearest month.
Estimating what you eat in your head is hard: portions, cooking oil and snacks get forgotten, and the error usually goes toward underestimating. Logging every meal, even roughly, makes that gap visible.
It's the gap when you eat fewer calories than you burn. Your body then draws on its reserves to make up the difference. Example: 2,650 kcal burned and 2,100 kcal eaten is a deficit of 550 kcal per day.
It depends on your maintenance. Cutting about 275 to 550 kcal per day from your maintenance corresponds to a loss of about 0.25 to 0.5 kg (0.5 to 1.1 lb) per week. The calculator does this for your profile and the pace you choose.
In the first weeks, it happens, mostly because of water. Over time, a deficit of more than 1,000 kcal per day is hard to sustain and can come at the expense of muscle. That's why the calculator caps the pace.
Yes, every few kilos (5 to 10 lb): your maintenance drops with your weight. Recalculate it with your new weight, or adjust your target if your loss clearly slows down for several weeks.
No, it calculates its own, with the same Mifflin-St Jeor equation but from the sports you report rather than an activity level. It then estimates a date for each kilo along the way, as a range. The two numbers can therefore differ.
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