How many calories should I eat to lose weight?
To lose weight, eat about 20% fewer calories than your maintenance, and never more than 500 fewer a day. For most women that is about 1,400 to 1,850 kcal a day and for most men about 1,900 to 2,650, but your own number depends on your size, age and how active you are. Work it out below in a few seconds.
By Simon, head coach at Zama Fitness. Updated 24 October 2026.
Calorie deficit calculator UK
To lose weight, eat about
1,610kcal a day
That is a deficit of 410 kcal a day, which should take off about 0.5 kg (1.0 lb) a week at first.
Maintenance calories
2,020
kcal a day to stay the same weight
Protein
156 g
a day, to keep muscle while you lose fat
- You burn about 2,020 kcal a day: your resting burn is 1,460, times 1.38 for a desk job and 3 training days a week.
- Fat loss: 403 kcal below your burn (20%, capped at 500) so you lose fat, not muscle.
- Protein is 2 g per kg of body weight.
This is your starting point. As you lose weight your burn drops, so the number has to change. Your coach changes it for you every four weeks.
For adults aged 18 and over. Not suitable in pregnancy or if you have, or have had, an eating disorder. Speak to your GP first if you have a health condition.
How the calculator works
The calculator uses the same rules our coaches use to set a member's starting target. There are three steps.
- Your resting burn. The calories your body uses at rest, from your sex, age, height and weight (the Mifflin-St Jeor equation, the one most dietitians use).
- Your maintenance calories. Your resting burn multiplied up for your day job and the number of workouts you do each week.
- Your deficit. 20% below maintenance, capped at 500 kcal a day, so you lose fat at a pace you can keep without losing muscle.
It never sets a target below 1,200 kcal for women or 1,500 kcal for men, or below your resting burn, whichever is higher. It also gives you a protein target, because eating enough protein is what keeps your muscle while the weight comes off.
Maintenance calories calculator UK: where everything starts
Your maintenance calories are what you would eat to stay exactly the same weight. Every weight-loss target is worked out from it, which is why a maintenance calories calculator is the first step for anyone trying to lose weight. The calculator above shows yours as "Maintenance calories", worked out for UK units in stone and kilos.
Maintenance is not fixed. It drops as you get lighter, because a smaller body burns less, and it changes with how active you are. That is the main reason weight loss slows after the first few weeks: the target that worked at the start is now closer to your new maintenance.
How many calories should a woman eat to lose weight?
Women tend to need fewer calories than men of the same weight, because they usually carry less muscle. These examples were worked out by the calculator above.
| Woman | Maintenance | To lose weight |
|---|---|---|
| 38, 5ft 5in, 12st 4lb, desk job, trains 3 days | 2,020 kcal | 1,610 kcal |
| 52, 5ft 3in, 11st, lightly active, trains 2 days | 1,820 kcal | 1,450 kcal |
| 29, 5ft 7in, 14st 2lb, desk job, trains 3 days | 2,290 kcal | 1,830 kcal |
Worked out with the calculator on this page, October 2026.
Age matters less than people think. Height, weight and how much you move in a day make the biggest difference, which is why two women of the same weight can need very different numbers.
And how many calories should a man eat to lose weight?
| Man | Maintenance | To lose weight |
|---|---|---|
| 40, 5ft 10in, 14st 13lb, desk job, trains 3 days | 2,580 kcal | 2,080 kcal |
| 30, 6ft, 13st 5lb, on his feet, trains 4 days | 3,120 kcal | 2,620 kcal |
| 55, 5ft 9in, 15st 10lb, desk job, trains 2 days | 2,410 kcal | 1,930 kcal |
Worked out with the calculator on this page, October 2026.
A man who is on his feet all day can eat far more than one at a desk and still lose weight. If your job is physical, choose "On my feet" or "Very active" in the calculator.
Why am I not losing weight on my calories?
When the scales stop moving, it is almost always one of these:
- Your maintenance has dropped as you lost weight, so your old target is no longer a deficit.
- Portions have crept up: oils, sauces, drinks and the odd snack add up faster than people think.
- Weekends undo the week. Five careful days and two big ones can cancel out the deficit.
- Water is hiding the loss. Salt, hormones, sleep and a hard workout can hold a few pounds of water for days.
The fix is to look at your weight trend over a month, not a single weigh-in, and change the target when the trend says so. That is what Weigh-In Day is for: every four weeks your coach reads your trend and adjusts your calories.
How fast should you lose weight?
Losing 0.5 to 1% of your body weight a week is a pace most people can keep while holding on to their muscle. For someone who weighs 12 stone, that is roughly 0.5 to 1 kg a week at the start, slowing as you get lighter.
Faster is possible, but the bigger the deficit, the harder it is to keep going and the more muscle you risk losing. The calculator caps the deficit at 500 kcal a day for that reason.
Calories and weight loss: your questions.
How many calories should I eat to lose weight?
Eat about 20% fewer calories than your maintenance, up to a maximum of 500 fewer a day. For most women that lands between about 1,400 and 1,850 kcal a day and for most men between about 1,900 and 2,650, depending on size, age and activity. Use the calculator for your own number.
How many calories should a woman eat to lose weight?
It depends on her size, age and how active she is. In our examples, a 52-year-old woman of 5ft 3in and 11st with a lightly active day needs about 1,450 kcal, and a 29-year-old woman of 5ft 7in and 14st 2lb with a desk job needs about 1,830.
Is 1,200 calories a day enough to lose weight?
It will usually cause weight loss, but for most adults it is lower than they need and hard to keep up. We never set a target below 1,200 kcal for women or 1,500 kcal for men, or below your resting burn, whichever is higher.
How many calories should I cut to lose a pound a week?
A common rule of thumb is about 500 kcal a day. In practice weight loss is faster in the first weeks, partly water, and slows as you get lighter, which is why your target needs updating as you go.
How to lose 2 stone in 12 weeks?
Two stone in 12 weeks is about 1 kg a week. That is realistic for some heavier people early on, but for most it is faster than is comfortable to sustain. Losing 0.5 to 1% of your body weight a week is a pace most people can keep.
Should I eat back the calories I burn exercising?
Not with this calculator. Your training days are already counted in your maintenance calories, so eating them back would cancel out your deficit.
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