Weight Loss Timeline Calculator: Your Goal Date
See how long it takes to reach your goal weight at a given calorie deficit, with a week-by-week curve and an estimated goal date.
Goal date
- Weight to lose
- 20.0 lb
- Weekly rate
- 1.00 lb
- Daily deficit
- 500 kcal
- Weekly deficit
- 3500 kcal
How the timeline works
Energy in vs energy out, with one constant: a pound of stored body fat holds about 3,500 kcal, and a kilogram holds about 7,700 kcal. Divide the total weight you want to lose by your weekly deficit and you get the number of weeks. From there it's a date on a calendar.
weeks = (weight to lose × density) / (daily deficit × 7)density = 7,700 kcal/kg or 3,500 kcal/lb
Why real loss slows
The calculator assumes your maintenance stays put. It doesn't. As you lose weight your BMR drops because there's less of you to power, and NEAT (fidgeting, posture, spontaneous activity) usually falls a little too. The deficit that produced a 1 lb/wk loss at 200 lb produces about 0.85 lb/wk at 180 lb. Plan to recalculate your maintenance every 10 lb of loss.
How to pick a realistic deficit
- 0.5% of bodyweight/week: Slow but comfortable, easy to sustain through life.
- 0.75% of bodyweight/week: The sweet spot for most people, fast enough to feel progress.
- 1% of bodyweight/week: Aggressive. Works for short cuts, expect more hunger and slightly more muscle loss.
- Above 1%: Only for very high body fat or contest-prep timelines, and only with high protein.
Worked examples
Example 1. 200 lb to 180 lb at a 500 kcal daily deficit. 20 lb × 3,500 = 70,000 kcal. ÷ 3,500/week = 20 weeks.
Example 2. 90 kg to 80 kg at 0.75 kg/week. 10 kg × 7,700 = 77,000 kcal. ÷ (0.75 × 7,700) = ~13.3 weeks. Daily deficit ≈ 825 kcal.
Example 3. 165 lb to 145 lb at 1.5 lb/week. 20 lb × 3,500 = 70,000 kcal. ÷ 5,250/week = ~13.3 weeks. Daily deficit ≈ 750 kcal.
What this calculator doesn't model
- Water weight swings (especially week one).
- Metabolic adaptation as you lose weight.
- Refeeds, diet breaks, training-day cycling.
- Hormonal cycles for women.
- Tracking error, which is the single biggest source of "the math isn't working".
FAQ
How is the timeline calculated?+
Total weight to lose × energy density (7,700 kcal/kg or 3,500 kcal/lb) ÷ weekly deficit. It assumes the deficit holds steady and the energy comes entirely from fat, which is a simplification.
Why does real loss slow down?+
As you lose weight your maintenance drops, so the same intake produces a smaller deficit. NEAT also falls slightly. Expect actual loss to slow by 10-20% by the time you've lost 10% of bodyweight.
What deficit should I use?+
0.5 to 1% of bodyweight per week is sustainable. That's roughly a 500-750 kcal/day deficit for most adults. Bigger deficits work short-term but cost more muscle and adherence.
Should I weigh daily or weekly?+
Daily weigh-ins averaged across the week give the clearest signal. Single readings bounce 1-2 kg from water, sodium and gut content.
What if I plateau?+
Recalculate your maintenance at your new weight, then re-set the deficit. A 3-week stall at the same intake usually means TDEE has dropped or tracking has drifted.
Does the curve account for water weight?+
No, it's a steady-state estimate. Expect a 2-4 lb water drop in week one (mostly glycogen) and similar bounces around carb-heavy days. Trend matters, not daily numbers.
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Related guides
- How Many Calories Should I Eat to Lose Weight?A practical answer with the math, the trade-offs of aggressive vs slow deficits, and the calories most people actually need.
- Cutting vs Bulking: How to Set Your NumbersHow to choose between a cut and a bulk, set realistic numbers, and recognize the signals telling you to switch.
- Weight Loss Plateau: Why You've Stalled and How to Break ItWhy plateaus happen, how to spot a real stall vs water-weight noise, and the four fixes that get the scale moving again.