Find out how many calories to eat each day to lose weight at a steady, safe pace, and roughly how long it will take to reach your goal weight.
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How a calorie deficit works
To lose weight you need to use more energy than you eat. A deficit of about 7,700 kcal is roughly equal to 1 kg of body fat, so a daily deficit of about 550 kcal leads to about 0.5 kg of loss a week. The NHS suggests aiming to lose 0.5 to 1 kg a week.
The calculator never sets a target below 1,200 kcal for women or 1,500 kcal for men. Going lower without medical supervision makes it hard to get enough nutrients and is difficult to sustain.
Worked example
A 35-year-old woman, 165 cm and 80 kg, with light exercise, maintains her weight on about 2,056 kcal a day. Eating about 1,506 kcal would mean losing roughly 0.5 kg a week, so reaching 70 kg would take about 20 weeks.
Making a deficit easier
- Build meals around protein and vegetables, which keep you fuller.
- Cut back on drinks with calories, such as sugary drinks and alcohol.
- Increase daily activity like walking, not just gym sessions.
- Expect weight to fluctuate from day to day; look at the trend over weeks.
If you’re pregnant, under 18, have a medical condition, or have a history of eating disorders, talk to a GP before starting a diet.
Frequently asked questions
How big should my calorie deficit be?
Around 500 to 600 kcal a day suits most people and leads to about 0.5 kg of loss a week.
Is 1,200 calories a day safe?
It’s generally the lowest level advised for women without medical supervision. Many people need more.
Why have I stopped losing weight?
As you lose weight your maintenance calories fall, so recalculate every few kilos. Water retention can also hide fat loss for a week or two.
Do I need to count calories?
Not necessarily. Some people prefer portion guides or simpler habits. The calculator gives a starting point.
Sources
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