Everyone online gives the same answer: 1 to 2 pounds a week, so divide and wait. That answer is the population average, and it's a fair place to start. It's also wrong for you by an amount nobody can know until you've logged a few weeks. Here's the math first, then the part it leaves out.
A pound of body fat holds about 3,500 calories, so a 500 calorie a day gap works out to a pound a week. That's the Wishnofsky figure from 1958. It's what the free calculator and most others run on, and Hall showed in 2008 that it gets less accurate the longer a diet runs. Here's what it says for common goals, at the three paces the calculator will plan for.
| Pounds to lose | Half a pound a week | A pound a week | Two pounds a week |
|---|---|---|---|
| 5 lb | 10 weeks | 5 weeks | 2.5 weeks |
| 10 lb | 20 weeks | 10 weeks | 5 weeks |
| 15 lb | 30 weeks | 15 weeks | 7.5 weeks |
| 20 lb | 40 weeks | 20 weeks | 10 weeks |
| 25 lb | 50 weeks | 25 weeks | 12.5 weeks |
| 30 lb | 60 weeks | 30 weeks | 15 weeks |
| 40 lb | 80 weeks | 40 weeks | 20 weeks |
| 50 lb | 100 weeks | 50 weeks | 25 weeks |
| 100 lb | 200 weeks | 100 weeks | 50 weeks |
Losing 5 pounds takes about 5 weeks at a pound a week, which is a 500 calorie a day gap. Half a pound a week makes it 10 weeks, two pounds makes it 2.5. The first week usually drops faster than that, and most of it is water, so don't set the pace off week one.
Losing 10 pounds takes about 10 weeks at a pound a week, which is a 500 calorie a day gap. Half a pound a week makes it 20 weeks, two pounds makes it 5. The first week usually drops faster than that, and most of it is water, so don't set the pace off week one.
About 15 weeks at a pound a week, which is a 500 calorie a day gap, so about 3.5 months. Two pounds a week gets there in 7.5, half a pound takes 30. That's the 3,500 calories per pound rule, and it's a population average. Your scale has the last word, and that's the number the HabitSync forecast reads.
About 20 weeks at a pound a week, which is a 500 calorie a day gap, so about 4.5 months. Two pounds a week gets there in 10, half a pound takes 40. That's the 3,500 calories per pound rule, and it's a population average. Your scale has the last word, and that's the number the HabitSync forecast reads.
About 25 weeks at a pound a week, which is a 500 calorie a day gap, so about 6 months. Two pounds a week gets there in 12.5, half a pound takes 50. That's the 3,500 calories per pound rule, and it's a population average. Your scale has the last word, and that's the number the HabitSync forecast reads.
About 30 weeks at a pound a week, which is a 500 calorie a day gap, so about 7 months. Two pounds a week gets there in 15, half a pound takes 60. That's the 3,500 calories per pound rule, and it's a population average. Your scale has the last word, and that's the number the HabitSync forecast reads.
Roughly 40 weeks at a pound a week, about 9 months. Two pounds a week is 20 weeks, and that's as fast as the calculator will plan for. That long, the math drifts: as you lose, you burn less, so the deficit you set in month one has shrunk by month six. Plan on resetting it more than once.
Roughly 50 weeks at a pound a week, about a year. Two pounds a week is 25 weeks, and that's as fast as the calculator will plan for. That long, the math drifts: as you lose, you burn less, so the deficit you set in month one has shrunk by month six. Plan on resetting it more than once.
Roughly 100 weeks at a pound a week, about 2 years. Two pounds a week is 50 weeks, and that's as fast as the calculator will plan for. That long, the math drifts: as you lose, you burn less, so the deficit you set in month one has shrunk by month six. Plan on resetting it more than once.
The usual answer is 1 to 2 pounds, and that's the range the calculator here plans in, from a quarter pound up to 2. Going faster means a calorie gap it won't set, since it holds the floor at 1,200 calories a day for women and 1,500 for men. A big first week is mostly water.
At 2 pounds a week, the fastest pace the calculator plans for, 50 pounds takes 25 weeks. At a pound a week it's 50. Most people land somewhere between, and slower than they expected, because the deficit shrinks as the weight comes off. Whether the faster end is right for you is a question for your doctor, not a calculator.
Run the free calculator with your stats and a pace, and it hands you a week count. Then log your weight in HabitSync and the 60 day forecast redraws that number from what the scale does, not what the formula guessed. If the two disagree, believe the scale.
The table rests on your calorie gap, and the gap rests on a TDEE estimate. Every formula for that number is a population average. It was fit to groups of people, and individuals scatter around the group line by a couple hundred calories either way. A 500 calorie gap on paper can be 300 in practice, or 700, and you'd never know from the formula. Here's how far off a TDEE calculator usually is.
Then the number moves. As you lose weight there's less of you to run, so you burn less, and a long diet quietly trims the fidgeting and the extra trips across the house too. The deficit you set in January isn't the deficit you're running in April. That's what most plateaus turn out to be: not a lapse, a maintenance number that drifted down while the plan stood still.
It keeps the formula as a starting point and then stops trusting it. Log your weight and the 60 day forecast redraws itself around what the scale is doing. If you're losing slower than the math said, the projection says so, and the timeline moves before you've lost a month to it.
With a few weeks of weight and calories logged, the paid plan goes a step further and works your maintenance backward from the trend, which replaces the population average with your own number. The forecast also labels which calories-in figure it ran on, a target you set, recently logged meals, or a plain estimate, so you always know how much to believe it. Pricing is here.
The calculator is free and asks for nothing. Run it, keep the estimate, and let a few weeks of logging tell you how close it was.