How to work out calories for a goal date by hand
- Count the weeks. Count the weeks from today to your goal date. 12 weeks, for example.
- Find the pace. Divide the weight you want to lose by the number of weeks. 6 kg over 12 weeks is 0.5 kg a week (13 lb over 12 weeks is about 1.1 lb a week).
- Check the cap. Keep the pace at or below 1% of your current weight a week. If it's higher, choose a later date.
- Turn the pace into calories. Multiply the pace in kg by 7,700 and divide by 7 (0.5 kg a week is 550 kcal a day), then subtract that from your maintenance calories.
- Check the minimum. If the result is below 1,200 kcal for women or 1,500 kcal for men, use that minimum and expect a later date.
How the weight loss calculator works
- Your maintenance calories. Mifflin-St Jeor BMR × your activity factor, exactly like the TDEE calculator.
- The pace your date needs. The weight between you and your goal, divided by the weeks until your date.
- The safety check. The pace is capped at 1% of your current body weight a week, and flagged above 0.75%. The daily target never goes below 1,200 kcal for women, 1,500 kcal for men or 1,350 kcal for “other”, in line with the reduced-calorie ranges in the 2013 AHA/ACC/TOS obesity guideline.
- Your plan. If the date passes the check, you get the daily calories to get there. If it doesn’t, you get the earliest safe date and the calories at the safe pace.
A goal weight below a BMI of 18.5 for your height isn’t planned at all: that’s under the healthy range in the NIH guidelines and the WHO categories.
Worked examples
Two people, both lightly active: a 35-year-old woman, 165 cm (5 ft 5 in), 80 kg (176 lb), whose maintenance is about 2,060 kcal a day, and a 40-year-old man, 180 cm (5 ft 11 in), 100 kg (220 lb), whose maintenance is about 2,650 kcal.
| Goal | Time | Pace needed | Daily target | Verdict |
|---|---|---|---|---|
| Woman: 80 → 70 kg | 20 weeks | 0.5 kg (1.1 lb) a week | 1,510 kcal | Within the safe pace |
| Woman: 80 → 70 kg | 8 weeks | 1.25 kg (2.8 lb) a week | 1,200 kcal | Too soon: earliest safe date in 13 weeks |
| Man: lose 20 lb (9.1 kg) | 12 weeks | 0.76 kg (1.7 lb) a week | 1,820 kcal | Allowed, flagged above 0.75% |
The woman’s 8-week date needs 1.25 kg a week, above her cap of 0.8 kg; even the capped pace would put her below 1,200 kcal, so her plan uses 1,200 kcal and reaches 70 kg in about 13 weeks instead of 8.
Picking a realistic date
- Start from the pace, then the date. 0.5 kg (about 1 lb) a week is a common, sustainable pace for many adults. The CDC notes that people who lose weight gradually and steadily, about 1 to 2 pounds a week, are more likely to keep it off.
- Leave room for real life. Holidays, illness and busy weeks happen. A date with a few spare weeks is one you’ll still believe in a month from now.
- Expect the line to bend. The calculator draws a straight line, but your energy needs fall as you lose weight, so progress usually slows. Modelling research in The Lancet describes how gradual that response is; the NIH’s Body Weight Planner models it in detail.
- Have an event in mind? If the date is fixed (a wedding, a trip), it’s better to arrive a little above your goal at a pace you enjoyed than to crash diet into it.
Not for teens, or during pregnancy
This calculator is for adults. The Calorix app never sets a calorie deficit for anyone under 18, and doesn’t set targets during pregnancy or breastfeeding: choose “Pregnant” or “Breastfeeding” and the calculator shows guidance instead. Your doctor, midwife or a registered dietitian can help you plan.
How Calorix keeps you on track
In Calorix you set your goal weight and pace during setup and see the projected date move as you adjust them, with the same cap and minimum as this page. After that, your weigh-ins build a smoothed trend, and the projection updates from your real progress. If you’d rather choose a pace and see the date, use the calorie deficit calculator.
