How Long Does It Take to Lose 20 Pounds?

Every date here comes from one piece of arithmetic: the 20-pound gap divided by your weekly pace gives the number of weeks. Because a pound of body fat stores roughly 3,500 calories, each pace maps to a daily deficit. A steady 1 lb a week runs on about a 500-calorie daily deficit and takes roughly 20 weeks. Step up to 1.5 lb a week — near 750 calories a day — and the 20 pounds are gone in about 13 weeks. The fastest safe rate, 2 lb a week, asks for a deficit close to 1,000 calories a day and finishes in about 10 weeks. That 2 lb pace sits at the very top of the accepted 0.5–2 lb per week range and suits mainly higher starting weights, where a larger body supports a bigger deficit. To turn any pace into a specific daily calorie number you first need your maintenance figure, which the TDEE Calculator estimates for you.

A straight-line estimate assumes the pace never changes, but over a 20-pound stretch it does. As you lose weight your maintenance calories fall, so the same intake produces a smaller and smaller deficit — and the tail of the plan runs slower than the early weeks suggest. The fix is not to eat less and less but to recalculate every 5 to 10 pounds, resetting the pace against your new, lower maintenance figure. Tracking the loss as a percentage of your starting weight rather than a raw pound count also keeps the milestones meaningful, since the same 5 pounds means more the lighter you get. The Weight Loss Percentage Calculator turns each milestone into a percentage so progress stays comparable across the whole 20 pounds.

The week counts above are the general shape; your own date depends on your numbers. Enter your current weight and a goal weight 20 pounds lower, add your height, age, gender and activity level, and the planner estimates your maintenance calories with the Mifflin-St Jeor equation, applies your chosen pace, and returns a specific projected date plus 25%, 50% and 100% milestones. If a pace would drive your intake below a safe floor, it caps the deficit and stretches the date rather than pretending an unsafe plan works. When you would rather set the deadline first and read off the pace it needs, the Goal Weight Calculator this page is built on runs the same maths from a deadline instead. These figures are general estimates for healthy adults, not medical advice.