Free tool
Calorie deficit calculator
Enter where you are and where you want to be. You get a daily calorie target, the weekly rate it implies, and a realistic timeline — with safe rate limits applied, so it will not suggest anything reckless.
How the target is worked out
The calculator aims to close the gap between your current and goal weight over about twelve weeks, then applies limits.
Roughly 7,700 calories correspond to a kilogram of body mass, so a weekly rate converts directly into a daily adjustment. Losing half a kilo a week works out at about 550 calories a day below maintenance.
Two caps then apply, and they are the important part. Loss is limited to 0.75 kg per week and gain to 0.35 kg per week, and the daily adjustment itself is bounded — no more than 750 calories below maintenance, and no more than 400 above. A large gap therefore produces a longer timeline rather than a more aggressive deficit.
Maintenance is calculated from the midpoint of your current and goal weight, so the target reflects the body you are moving toward rather than only the one you have now.
Why the timeline is longer than you hoped
Most people arrive at a deficit calculator wanting to hear a number of weeks that is about half what it says. It is worth understanding why the caps are there rather than working around them.
Very aggressive deficits cost muscle alongside fat, which lowers your maintenance calories and makes the next stretch harder. They also tend to break: hunger, low energy and a joyless diet win eventually, and the rebound usually undoes the progress.
A moderate deficit you can hold for four months beats an extreme one you abandon in three weeks. The caps here exist to keep the suggested plan inside the range people actually complete.
The part the calculator cannot do
A daily target is only useful if you know what you have eaten against it. Most deficits fail not because the number was wrong but because after nine days of searching a food database nobody is still logging.
This is the whole reason BetterCal exists. You say or type “two rotis, dal and curd” and the day is recorded. Repeat meals are one tap. A deficit you can actually measure is a deficit that works.
Frequently asked questions
How big should a calorie deficit be?
For most people 300–500 calories below maintenance is the sustainable range, giving roughly 0.25–0.5 kg a week. Larger deficits work in the short term but get harder to hold and cost more muscle.
Why does it say I am at my goal weight?
If your current and goal weights are within half a kilogram, no adjustment is applied and the target is simply maintenance. Half a kilo is inside normal daily fluctuation, so there is nothing meaningful to correct.
Why has my weight stopped moving?
Usually one of three things: maintenance has dropped as you have lost weight, activity has been overestimated, or intake has crept up. Recalculate with your current weight, check the activity level honestly, and log for a fortnight before changing anything.
Can I use this to gain weight?
Yes — set a goal weight above your current one and you get a surplus, capped at 400 calories a day. That is deliberately modest, because larger surpluses mostly add fat rather than muscle.
Is this medical advice?
No. It is a general calculator based on standard formulas. If you have a medical condition, are pregnant, or are planning a substantial change to how you eat, speak to a doctor or a registered dietitian.
Next step
Track the deficit without the work.
Free to start on iPhone and Android.
