To lose weight you need to eat less energy than you burn. Your maintenance calories are the starting point. The sections below turn that into a daily target and a realistic timeline.
Step 1: Find your maintenance energy
Use the calculator to get your TDEE in Calories and kilojoules. Your results already include weight-loss targets for 0.25 kg and 0.5 kg a week.
Step 2: Choose a deficit
About 7,700 Cal (32,200 kJ) of energy is stored in a kilogram of body fat, so the arithmetic is simple:
| Weekly loss | Daily deficit (Cal) | Daily deficit (kJ) | Who it suits |
|---|---|---|---|
| 0.25 kg | ≈ 275 | ≈ 1,150 | Gentle, easiest to sustain, good for smaller deficits or lower body weight |
| 0.5 kg | ≈ 550 | ≈ 2,300 | Standard pace for most adults |
| 0.75 kg | ≈ 825 | ≈ 3,450 | Only with a higher starting weight and ideally professional guidance |
Minimum intake: avoid eating below about 1,200 Cal (5,000 kJ) a day for women or 1,500 Cal (6,300 kJ) for men unless supervised by a doctor or Accredited Practising Dietitian.
How long will it take?
| Weight to lose | At 0.5 kg / week | At 0.25 kg / week |
|---|---|---|
| 5 kg | 10 weeks | 20 weeks |
| 10 kg | 20 weeks | 40 weeks |
| 15 kg | 30 weeks | 60 weeks |
| 20 kg | 40 weeks | 80 weeks |
Add your goal weight under Advanced options in the calculator for a personalised timeline. Expect the pace to slow, since a lighter body burns slightly less.
Step 3: Make the deficit work
- Prioritise protein (around 1.6 g per kg bodyweight) and do resistance training to protect muscle.
- Move more in everyday life. Steps and general activity add up. Australian guidelines recommend at least 150 minutes of moderate activity a week.
- Watch liquid energy: alcohol, soft drink, juice and café drinks can add 600–1,500 kJ each.
- Review every 2–4 weeks. If your weight hasn't moved, reduce intake or increase activity by about 100–200 Cal (400–800 kJ).
Read the full calorie deficit guide for practical steps and troubleshooting.
Frequently asked questions
How many calories should I eat to lose weight?
Start from your maintenance Calories and subtract about 275 Cal (1,150 kJ) a day to lose roughly 0.25 kg a week, or about 550 Cal (2,300 kJ) a day to lose roughly 0.5 kg a week. Do not go below 1,200 Cal (5,000 kJ) for women or 1,500 Cal (6,300 kJ) for men without medical supervision.
How long will it take to lose 10 kg?
At 0.5 kg a week it takes about 20 weeks, and at 0.25 kg a week about 40 weeks. Real progress is rarely a straight line, so judge by the 2–4 week trend.
Why am I not losing weight in a deficit?
Common reasons are underestimating intake, overestimating activity, water retention masking fat loss, or a deficit that is too small to see over a short window. Track weight and intake consistently for 3–4 weeks before changing anything.
Not suitable for under 18s, pregnancy, breastfeeding or anyone with a history of disordered eating. Speak to your GP first.