How Long Does It Take to Lose 10, 20 or 50 Pounds? Timeline Table

Weeks to a loss equal the amount divided by the weekly rate. At a steady 1 lb per week, 10 lb is 10 weeks, 20 lb is 20 weeks, and 50 lb is 50 weeks. At 0.5 kg per week, 10 kg is 20 weeks. The CDC describes about 1 to 2 lb per week as a gradual, steady pace. A straight line is usually early: the rate often slows as weight drops, and water and plateaus add time. These figures are planning arithmetic, not a personal plan.

The only formula in the table

A constant-rate timeline is division:

weeks = amount to lose ÷ weekly rate

The projected calendar date is today plus those weeks, times 7 days. Nothing else is inside the tables below. They do not know your age, your meals, or your training. If the rate changes, you divide again. That is the same step the goal weight date calculator uses in plan mode: current weight minus goal weight, divided by the weekly rate.

Read every cell as "if this rate held the whole way." It is a planning sketch, not medical advice. Talk to a clinician for a personal target, especially if you are pregnant, under 18, or have a medical condition.

Pounds: 5, 10, 15, 20, 30 and 50 lb

Rows are the loss. Columns are the weekly rate. A cell is the row divided by the column, rounded to one decimal when the result is not a whole number. 10 ÷ 1.5 = 6.666…, shown as 6.7 weeks. 20 ÷ 1.5 = 13.333…, shown as 13.3 weeks. 50 ÷ 1.5 = 33.333…, shown as 33.3 weeks.

Kilograms, and the conversion

NIST Special Publication 811 lists the avoirdupois pound as 4.535924 × 10⁻¹ kg. Inverting that factor and rounding to five decimal places gives 1 kg = 2.20462 lb. From that:

• 1 lb = 1 ÷ 2.20462 = 0.45359 kg, which rounds to about 0.45 kg. So 1 lb per week is about 0.45 kg per week.
• 0.5 kg × 2.20462 = 1.10231 lb, about 1.1 lb. So 0.5 kg per week is about 1.1 lb per week.
• 2 lb per week is about 0.91 kg per week (2 × 0.45359).

The kilogram grid uses the same division. 2 ÷ 0.75 = 2.666…, shown as 2.7 weeks. 5 ÷ 0.75 = 6.666…, shown as 6.7. 10 ÷ 0.75 = 13.333…, shown as 13.3. 20 ÷ 0.75 = 26.666…, shown as 26.7.

Ten kilograms is 10 × 2.20462 = 22.0 lb. At 0.5 kg per week the table says 20 weeks. At 1 lb per week, 22 lb is about 22 weeks. The two answers differ because 0.5 kg per week is about 1.1 lb per week, not 1.0.

The same rate as a percent of body weight

A weekly rate is also a percent of whatever you weigh now. One percent of 200 lb is 2 lb. Half a percent of 200 lb is 1 lb. One percent of 100 kg is 1 kg. Half a percent of 100 kg is 0.5 kg.

On a 200 lb body, the 1 lb/week column is 0.5% per week and the 2 lb/week column is 1% per week. The same 1 lb per week is 1 ÷ 150 = 0.67% of 150 lb. The tables do not change with body weight. The percent does.

The CDC's Steps for Losing Weight describes a gradual, steady pace of about 1 to 2 pounds a week, and says people who lose at that pace are more likely to keep it off than people who lose quicker. The same page calls losing 20 pounds in 2 weeks unrealistic — that would be 10 lb per week. It also notes that 5% of 200 pounds is 10 pounds. At 1 lb per week, that 10 pounds is the 10-week cell. The CDC is describing a modest loss, not timing it. This is not a target this page assigns to you. See the calculator's realistic pace note, and talk to a clinician before you pick a rate.

Worked example: 200 lb, 20 lb to go

Start at 200 lb. Goal 180 lb. Amount = 20 lb. This is the same pair the calculator uses as a plan-mode illustration (200 → 180 lb at 1 lb/week = 20 weeks).

• At 0.5 lb/week: 20 ÷ 0.5 = 40 weeks (280 days).
• At 1 lb/week: 20 ÷ 1 = 20 weeks (140 days).
• At 1.5 lb/week: 20 ÷ 1.5 = 13.3 weeks.
• At 2 lb/week: 20 ÷ 2 = 10 weeks.

In kilograms, 200 ÷ 2.20462 = 90.72 kg, and 20 lb is 9.07 kg. At 0.5 kg per week, 9.07 ÷ 0.5 = 18.1 weeks. At about 0.45 kg per week (1 lb per week), the same 9.07 kg is 20 weeks again.

Get your own projected date from your numbers, in pounds or kilograms. Plan mode takes a rate you type. A second mode fits a line through weigh-ins you paste.

Why the real timeline usually lands later

A straight line assumes this week's rate continues. Three ordinary things push the date out. The calculator walks through the same idea under why the real date is usually later.

The rate slows as weight drops

A lighter body spends less energy on the same day, so the same meals leave a smaller deficit and the weekly loss shrinks. The NIH/NIDDK Body Weight Planner is built for that. Hall and Chow (2013) make the related point about the "3,500 kcal per pound" rule: a fixed energy gap overestimates loss, because expenditure changes as weight changes.

A sketch of the shape, not a measured slowdown: the first 10 lb at 1 lb per week take 10 weeks, and the next 10 lb at 0.7 lb per week take 10 ÷ 0.7 = 14.3 weeks. The 20 lb then takes 24.3 weeks, not the table's 20.

Water swings hide the line for a while

The scale moves for reasons that are not fat. Salt, carbohydrate and glycogen, a new workout, and the time of day can all shift a morning. A week that looks "off" the table may be water sitting on top of a slower fat change. For the size of an ordinary day, see daily weight fluctuation. Judge the pace from a run of mornings, not from the noisiest one.

Plateaus add calendar time the table never had

A flat stretch does not appear in "weeks = amount ÷ rate," because that formula has no weeks at a rate of zero. A few flat weeks move the finish line by those weeks, and sometimes by more if the rate after the stall is slower than the rate you typed. How to tell a stall from noise is covered in weight loss plateaus and trend lines.

How the forecast works states the same limit: a straight line assumes your recent pace continues, and loss often slows. The page shows one projected date, not a range, and it does not publish a measured accuracy figure. Revisit the estimate as you log.

A typed rate and a line through your weigh-ins

The tables answer "if I held this rate." They cannot tell you whether you are holding it. Plan mode on the calculator divides a gap by a rate you type. Life Forecast's goal date does not use the table. It fits an ordinary least-squares line through the last 30 days of weigh-ins, one per day (morning preferred), at least 3 weigh-ins, with no extra smoothing. Calories, workouts, and Garmin data do not enter that date. The chart's 7-day average is not that line. Full rules are on how the forecast works.

Life Forecast is free, with no ads and no paid tier. A Garmin smart scale can sync weigh-ins through Garmin Connect, and meals can be logged by voice or photo. None of that changes the division in the table.

FAQ

How long does it take to lose 20 pounds?

Divide 20 by your weekly rate. At 1 lb per week that is 20 weeks. At 0.5 lb per week it is 40 weeks. At 2 lb per week it is 10 weeks. These are planning figures if the rate stayed constant. Real timelines often run later. Talk to a clinician for a personal target.

How long does it take to lose 10 kg?

Divide 10 by your weekly rate in kilograms. At 0.5 kg per week that is 20 weeks. At 0.25 kg per week it is 40 weeks. At 1 kg per week it is 10 weeks. The same arithmetic in pounds uses 1 kg = 2.20462 lb, so 10 kg is about 22.0 lb.

Is 1 to 2 pounds a week a gradual pace?

The CDC describes a gradual, steady pace of about 1 to 2 pounds a week, and says people who lose at that pace are more likely to keep the weight off than people who lose quicker. That is public-health guidance, not a prescription. Personal targets belong with a clinician.

Why is my real date later than the table?

A table assumes the weekly rate never changes. As weight falls, energy needs fall, so the same habits often produce a smaller deficit. Water swings and plateaus also push the calendar later than a straight line. The goal weight date calculator explains this on the page section about why the real date is usually later.

Does Life Forecast use this table for my goal date?

No. The table is arithmetic from a rate you choose. Life Forecast fits a straight least-squares line through your weigh-ins from the last 30 days (one per day, at least 3) and projects where that line meets your goal. There is no extra smoothing. The date is an estimate and it moves as you log.

Sources

• CDC — Steps for Losing Weight (gradual pace of about 1 to 2 pounds a week; 20 pounds in 2 weeks called unrealistic; 5% of 200 pounds = 10 pounds)
• NIST Special Publication 811, Appendix B (avoirdupois pound = 4.535924 × 10⁻¹ kg)
• Hall and Chow, 2013 — Why is the 3500 kcal per pound weight loss rule wrong?
• NIH/NIDDK Body Weight Planner

General information, not medical advice. The tables are arithmetic at a constant rate. Talk to a clinician for a personal target. Projected dates are estimates, not guarantees.