Calorie deficit calculator
Calorie Deficit Calculator
A calorie deficit is eating less than you burn. Find maintenance (TDEE) with Mifflin-St Jeor and an activity factor, then subtract enough to lose about 0.5–1 kg a week — the pace the NHS recommends. The calculator on this page does that math.
How a calorie deficit is calculated
This page uses the same engine as the TDEE calculator. Basal burn comes from the Mifflin-St Jeor equation (Mifflin et al., 1990):
- Men: (10 × kg) + (6.25 × cm) − (5 × age) + 5
- Women: (10 × kg) + (6.25 × cm) − (5 × age) − 161
- TDEE: that result × an activity factor from 1.2 to 1.9
- Target: TDEE minus the daily deficit for your chosen pace
If you know body fat, the Katch-McArdle equation can estimate resting burn from lean mass. This calculator stays with Mifflin-St Jeor because it does not need a body-fat measurement. Activity multipliers are the same table as on the TDEE page: 1.2 sedentary, 1.375 light, 1.55 moderate, 1.725 very active, 1.9 extra active.
Safe deficit range
The NHSsays to aim to lose 1 to 2 lb, or 0.5 to 1 kg, a week. The National Institute of Diabetes and Digestive and Kidney Diseasespoints to the Dietary Guidelines advice to take in fewer calories, and to theBody Weight Plannerfor a personal goal. A faster cut is harder to hold and more likely to cost muscle.
| Weekly pace | Traditional daily deficit | What to expect |
|---|---|---|
| 0.25 kg / 0.5 lb | about 275 kcal | Easier to keep up |
| 0.5 kg / 1 lb | about 550 kcal | Inside the NHS range |
| 1 kg / 2 lb | about 1,100 kcal | Top of the NHS range |
Those deficits use the traditional estimate of about 7,700 kcal per kilogram (3,500 kcal per pound). Treat them as a starting plan, then judge by the scale over two or three weeks.
Calorie floors
MedlinePlus, a National Library of Medicine site, describes usual low-calorie diets as about1,200 to 1,500 kcal a day for women and 1,500 to 1,800 kcal a day for men. If the calculator’s target is under the low end of that range, pick a slower pace. Very low intakes are a medical decision, not a default setting.
Weeks to goal
Weeks = kilograms to lose ÷ weekly pace. The dates assume the pace stays constant, which it will not forever.
| To lose | 0.25 kg/week | 0.5 kg/week | 1 kg/week |
|---|---|---|---|
| 2 kg (about 4.4 lb) | 8 weeks | 4 weeks | 2 weeks |
| 5 kg (about 11 lb) | 20 weeks | 10 weeks | 5 weeks |
| 10 kg (about 22 lb) | 40 weeks | 20 weeks | 10 weeks |
For a date from your own goal weight, use the weight loss calculator.
Worked example
A 35-year-old man, 178 cm, 90 kg, lightly active (1.375):
- BMR: (10 × 90) + (6.25 × 178) − (5 × 35) + 5 = 900 + 1,112.5 − 175 + 5 = 1,843 kcal
- TDEE: 1,843 × 1.375 = 2,534 kcal
- 0.5 kg/week: deficit about 550 kcal → target about 1,980 kcal/day
- 5 kg: about 10 weeks at that pace
1,980 kcal is above the MedlinePlus low-calorie range for men, so this pace does not hit the floor.
TDEE, BMR, and RMR
BMR is energy at rest under strict conditions.RMR is the resting figure measured with fewer restrictions.TDEE is resting burn plus movement and exercise. Subtract the deficit from TDEE, not from BMR. A longer comparison is onBMR vs RMR vs TDEE.
Common mistakes
- Setting activity too high. A few workouts do not make a desk job “very active.”
- Logging the plan, not the plate. Oil, drinks, and bites add up. See how to count calories.
- Cutting under the floor to force a faster date.
- Judging one week. Water and glycogen move the scale. Use two to three weeks.
- Never recalculating. A lighter body has a lower TDEE. Update the numbers after a few kilograms.
Use the number
Pair the target with the macro calculator and thefood calorie chart. The guidewhat is a calorie deficit explains the idea without the form. The MyPlate app is free to download, try every feature free, with a 3-day free trial.
Frequently asked questions
What is a calorie deficit?
A calorie deficit means eating fewer calories than you burn in a day (your TDEE). Your body makes up the gap from stored energy. That is the mechanism behind fat loss.
How big should my calorie deficit be?
The NHS says to aim for about 0.5 to 1 kg (1 to 2 lb) a week. Using the traditional estimate of about 7,700 kcal per kilogram, that pace is roughly a 550 to 1,100 kcal daily deficit. Many people do better near the slower end.
How do I calculate my calorie deficit?
Estimate TDEE with Mifflin-St Jeor times an activity factor, then subtract the deficit that matches your weekly pace. This calculator does both and shows a sample timeline.
What is a low calorie floor?
MedlinePlus describes usual low-calorie diets as about 1,200 to 1,500 kcal a day for women and 1,500 to 1,800 kcal a day for men. If your target lands below that range, slow the pace instead of cutting further without medical advice.
How many weeks will a goal take?
Divide the weight you want to lose by your weekly pace. At 0.5 kg a week, 5 kg takes about 10 weeks. The table on this page shows 2 to 10 kg at three paces.
Is 3,500 calories one pound of fat?
That is the traditional estimate (about 7,700 kcal per kilogram). It is a planning shortcut. Loss is not perfectly linear because a smaller body burns less, so recalculate after you have lost some weight.
Why am I in a deficit but not losing weight?
The usual reasons are portions that are larger than you logged, an activity level set too high, or water weight hiding fat loss for a week or two. Log consistently for two to three weeks, then adjust. See the guide on not losing weight in a deficit.
Is a calorie deficit calculator free?
Yes. The calculators on myplate.world are free. The MyPlate app is free to download, try every feature free, with a 3-day free trial.