Can I lose 30 lb in 3 months?

Thirty pounds over about 13 weeks is roughly 2.3 lb a week — at or just past the top of the 0.5–2 lb per week range, needing a daily deficit near 1,150 calories. It is achievable mainly at higher starting weights. For most people the realistic 3-month figure is closer to 13–26 lb.

Can I lose 20 lb in 3 months?

Yes — 20 lb over about 13 weeks is roughly 1.5 lb a week, comfortably inside the 0.5–2 lb per week range and needing a daily deficit near 750 calories. It is one of the more realistic amount-and-deadline pairings, especially if you recalculate as your maintenance calories drop.

Is a 3-month goal enough time?

That depends on the gap you are trying to close. Divide the pounds you want to lose by a safe pace — 0.5 to 2 lb a week — to see if it fits inside roughly 13 weeks. Amounts up to about 25 lb usually fit comfortably; much beyond that pushes the required pace past the safe range and is better given more time.

Timeline & Planning

How Much Weight Can I Lose in 3 Months?

At safe paces a realistic 90 days is about 13–26 lb (6–12 kg). Enter your numbers to project your own 3-month figure and goal date.

Calculate Your Plan

Current Weight

Range: 30–300 kg · up to 2 decimals

Goal Weight

Range: 30–300 kg · up to 2 decimals

Height

cmft·in

Enter your height in centimeters (e.g., 170 cm)

Age

Range: 18–100 years

Gender

Required: the BMR formula uses biological sex (male or female) as a variable, so the estimate can’t be calculated without it.

Activity Level

Planning Method

Duration

weeks

*This calculator is for informational purposes only. Please consult a healthcare professional before making any health decisions. See our medical disclaimer for more information.

Date-Based Planning

Have a wedding, vacation, or competition coming up? Select “By Duration” to enter a number of days, weeks, or months and let the algorithm reverse-engineer your required daily deficit.

The calculator will block any target duration that requires a daily deficit above 1,000 calories, and warn if the resulting intake falls below clinical minimums.

The 7,700 kcal/kg Rule

A kilogram of body fat contains approximately 7,700 calories. To lose 0.5 kg per week, you need a daily deficit of 550 calories (550 × 7 = 3,850).

Pace	Deficit/Day
0.25 kg / wk	275 kcal
0.50 kg / wk	550 kcal
0.75 kg / wk	825 kcal
1.00 kg / wk	1,100 kcal

Safe Loss Rates

Aggressive deficits lead to muscle wasting. A safe clinical guideline is to aim for losing 0.5% to 1.0% of your total body weight per week.

70 kg person:0.35 – 0.70 kg/wk
90 kg person:0.45 – 0.90 kg/wk
110 kg person:0.55 – 1.0 kg/wk *

* 1% of body weight would be 1.10 kg/wk. This tool caps the selectable rate at 1.0 kg/wk — a pace suited mainly to higher body weights. At most body weights a 1.0 kg/wk rate implies an ~1,100 kcal/day deficit, above the 1,000 kcal/day guideline, which is why it is flagged "Very Aggressive".

Reverse Dieting

When you hit your goal weight, gradually add 100–200 calories back per week until your weight stabilises. Your metabolism has adapted — jumping straight to maintenance calories causes rebound fat gain.

Quick Answer

How Much Weight Can I Lose in 3 Months?

Three months is about 13 weeks, so at a safe 1–2 lb (0.5–1 kg) per week the realistic range is roughly 13–26 lb (6–12 kg). Higher starting weights land near the top; lighter bodies near the bottom. Enter your current weight, goal weight and activity level and the planner — preset to a 90-day deadline — reverses that timeline into the daily calorie target it requires.

How It's Derived

The 3-month figure is a single piece of arithmetic. Three months runs to about 13 weeks, so you multiply your weekly pace by 13. A gentle 1 lb a week works out to roughly 13 lb over the stretch, a moderate 1.5 lb a week to about 20 lb, and the fastest safe rate of 2 lb a week to about 26 lb. That is why the realistic 90-day band sits around 13–26 lb (6–12 kg) for most people. The planner works the other way round: instead of picking a pace, you set a 3-month deadline and it reverses the maths, dividing the weight you want to lose across the 13 weeks and translating that into the daily deficit it needs. To see how that daily number is built from food and activity, the Calorie Deficit Calculator breaks it down.

Why the Tail May Lag

A 90-day run rarely holds one steady pace from start to finish. As you lose weight your body needs fewer calories to run, so your maintenance figure drifts downward and the same eating pattern buys a smaller and smaller deficit as the weeks pass. Metabolic adaptation nudges the same way. The upshot is that the last weeks of a three-month stretch are usually slower than the first, even when nothing about your effort changes. The calculator uses a static maintenance estimate and cannot model that gradual drift, so it is best to treat the top of the range as a ceiling rather than a promise and to recalculate every 5–10 lb as your numbers shift. To refresh the maintenance baseline the whole projection rests on, the TDEE Calculator re-estimates it from your current weight.

Setting a 90-Day Target Date

The band above is the general shape; your own number depends on your body. Enter your current weight and a goal weight, add your height, age, gender and activity level, and the planner estimates your maintenance calories with the Mifflin-St Jeor equation, spreads the loss across the 13 weeks, and returns a specific projected figure and date along with a milestone schedule. The Goal Weight Calculator this page is built on runs the same maths — here it is preset to three months, so it reports the weight you can reasonably reach in that window and the daily target it takes. These figures are general estimates for healthy adults, not medical advice.

Projections use the energy model of body fat (Hall et al., 2011) with maintenance estimated by the Mifflin-St Jeor equation (1990). A safe pace is 0.5–2 lb (0.25–1 kg) per week with a daily deficit up to about 1,000 kcal (NHS). Individual results vary.

CDC Assessment Guide