⚖️ Weight Loss Calculator
Enter your current weight, your goal and how fast you plan to lose. You get the number of weeks, an estimated goal date and the approximate daily calorie deficit.
How the Weight Loss Calculator works
The weeks needed are the weight to lose divided by the weekly rate. The deficit uses the common rule of thumb of about 3,500 calories per pound (7,700 per kilogram). Real loss usually slows over time, so treat the date as a rough guide.
Step-by-step calculation
- 1Enter current and goal weight.
- 2Enter your planned weekly loss.
- 3Divide the weight to lose by the weekly rate.
- 4Estimate the daily calorie deficit.
Worked example
Losing from 200 lb to 180 lb at 1 lb a week takes about 20 weeks and a deficit of about 500 calories a day.
Weight Loss Calculator examples
| Current weight | Time to goal |
|---|---|
| 200 | 20 weeks |
| 250 | 70 weeks |
| 300 | 120 weeks |
Other inputs kept at the calculator's default values. Results calculated by this calculator.
Why use a Weight Loss Calculator?
Set a realistic timeline for a weight goal.
Important factors that can affect your results
- Loss slows over time.
- Water weight swings.
- Medical conditions and medications.
Frequently asked questions
What is a safe rate?
The CDC suggests a gradual, steady loss of about 1 to 2 pounds a week for most adults.
Why does weight loss slow down?
As you lose weight your body needs fewer calories, so the same diet creates a smaller deficit.
Related calculators
Last reviewed November 2026 · How we build and check our tools · Report a problem