How Long Would It Take to Get a Healthy Weight?
We used real calculators to find out exactly how long it takes to reach a healthy BMI with safe weight loss methods.
You want to get to a healthy weight, but how long will it actually take? We ran the numbers using real calculators to give you honest timelines based on safe, sustainable weight loss.
What Is a "Healthy Weight"?
A healthy weight is typically defined by your Body Mass Index (BMI). According to NHS guidelines:
| BMI Range | Category |
|---|---|
| Under 18.5 | Underweight |
| 18.5 - 24.9 | Healthy Weight |
| 25.0 - 29.9 | Overweight |
| 30.0+ | Obese |
Using our BMI Calculator, you can find your current BMI and see exactly how much weight you'd need to lose to hit the healthy range.
Real Examples: How Long Does It Take?
Let's look at some real scenarios using our calculators.
Example 1: Overweight Person Wanting to Reach Healthy BMI
Profile:
- Current weight: 90 kg (14 stone 2)
- Height: 173 cm (5'8")
- Current BMI: 30.1 (obese)
- Target BMI: 24.9 (top of healthy range)
- Target weight: 74.5 kg (11 stone 10)
- Weight to lose: 15.5 kg (2.4 stone)
We entered these numbers into our Weight Loss Calculator with a moderate 500-calorie daily deficit:
| Weight Loss Rate | Daily Deficit | Time to Goal |
|---|---|---|
| 0.5 kg/week | 550 calories | 31 weeks (7.5 months) |
| 0.75 kg/week | 825 calories | 21 weeks (5 months) |
| 1 kg/week | 1100 calories | 15 weeks (4 months) |
Interpretation: Losing 15.5 kg safely takes 4-7.5 months depending on how aggressive your calorie deficit is.
Example 2: Moderately Overweight
Profile:
- Current weight: 80 kg (12 stone 8)
- Height: 168 cm (5'6")
- Current BMI: 28.3 (overweight)
- Target weight: 70 kg (11 stone) for BMI: 24.8
- Weight to lose: 10 kg (1.5 stone)
| Weight Loss Rate | Daily Deficit | Time to Goal |
|---|---|---|
| 0.5 kg/week | 550 calories | 20 weeks (5 months) |
| 0.75 kg/week | 825 calories | 13 weeks (3 months) |
Interpretation: A 10 kg loss at a healthy pace takes 3-5 months.
Example 3: Significantly Overweight
Profile:
- Current weight: 120 kg (18 stone 13)
- Height: 178 cm (5'10")
- Current BMI: 37.9 (obese class II)
- Target weight: 79 kg (12 stone 6) for BMI: 25
- Weight to lose: 41 kg (6.5 stone)
| Weight Loss Rate | Daily Deficit | Time to Goal |
|---|---|---|
| 0.5 kg/week | 550 calories | 82 weeks (19 months) |
| 0.75 kg/week | 825 calories | 55 weeks (13 months) |
| 1 kg/week | 1100 calories | 41 weeks (10 months) |
Interpretation: Major weight loss takes time. Expect 10-19 months for significant changes.
The Science Behind Weight Loss
Weight loss follows simple physics, even if it doesn't always feel simple:
- 1 kg of fat = approximately 7,700 calories
- 0.5 kg of fat = approximately 3,850 calories
To lose 0.5 kg per week, you need a daily deficit of about 550 calories (550 x 7 = 3,850).
Our Weight Loss Calculator does this maths for you and lets you adjust any variable:
- Set your target weight loss, and it calculates the time needed
- Set your timeframe, and it tells you the daily deficit required
- See food equivalents (e.g., "skip 2 fizzy drinks daily")
What Does a 500-Calorie Deficit Look Like?
A 500-calorie daily deficit can be achieved through:
Food Cuts (Easier Than You Think)
| Food | Calories | Frequency |
|---|---|---|
| Skip a Costa Frappuccino | 400-500 | Daily |
| Skip the chips with lunch | 350 | Daily |
| One less fizzy drink | 140 | 3x daily |
| Skip pudding | 300-500 | Daily |
| Smaller dinner portions | 200-300 | Daily |
Exercise (Harder Than Most Expect)
| Activity | Time for 500 calories | Difficulty |
|---|---|---|
| Running (10 km/h) | 45 min | High |
| Cycling | 60 min | Medium |
| Walking (brisk) | 90 min | Low |
| Swimming | 45 min | Medium |
***** Diet beats exercise for weight loss. Skipping a 500-calorie pudding takes 2 seconds. Burning 500 calories through exercise takes 45-90 minutes. Use our Calories Burned Calculator to see how much effort exercise really requires.
Safe vs. Aggressive Weight Loss
The NHS guidelines are clear:
| Rate | Per Week | Is It Safe? |
|---|---|---|
| Slow | 0.25 kg | Very safe, sustainable |
| Moderate | 0.5 kg | Safe, recommended |
| Aggressive | 0.5-1 kg | OK short-term |
| Very Fast | 1+ kg | Not recommended |
Why fast weight loss is risky:
- Muscle loss (you lose strength, not just fat)
- Nutritional deficiencies
- Gallstones
- Metabolic slowdown (harder to keep weight off)
- Fatigue and irritability
Your Personal Timeline
Use our calculators to find your specific timeline:
Step 1: Find your target weight
- Go to our BMI Calculator
- Enter your height and weight
- Note the weight needed for BMI of 24.9 (healthy range)
Step 2: Calculate your timeline
- Go to our Weight Loss Calculator
- Enter how much weight you want to lose
- Choose your preferred rate (we recommend 0.5-0.75 kg/week)
- See exactly how long it will take
Try it yourself:
<div style="margin: 1.5rem 0; padding: 1.5rem; background: linear-gradient(to right, #f0f9ff, #eff6ff); border: 2px solid #bfdbfe; border-radius: 0.75rem;"> <a href="/uk/calculators/weight-loss" style="text-decoration: none; color: inherit; display: block;"> <div style="display: flex; align-items: flex-start; gap: 1rem;"> <span style="font-size: 2.5rem;">⚖️</span> <div style="flex: 1;"> <h4 style="margin: 0 0 0.5rem 0; font-size: 1.125rem; font-weight: 600; color: #1f2937;"> Weight Loss Calculator → </h4> <p style="margin: 0; font-size: 0.875rem; color: #4b5563;"> Calculate weight loss timeline, calorie deficit, or target weight with flexible inputs </p> </div> </div> </a> </div>Realistic Expectations
Here's what the numbers tell us:
| Weight to Lose | At 0.5 kg/week | At 0.75 kg/week |
|---|---|---|
| 5 kg | 10 weeks | 7 weeks |
| 10 kg | 20 weeks (5 months) | 13 weeks (3 months) |
| 15 kg | 30 weeks (7 months) | 20 weeks (5 months) |
| 20 kg | 40 weeks (10 months) | 27 weeks (6.5 months) |
| 30 kg | 60 weeks (14 months) | 40 weeks (10 months) |
| 40 kg | 80 weeks (18 months) | 53 weeks (1 year) |
! These are minimums. Real weight loss includes plateaus, holidays, and life events. Add 20-30% extra time for realistic expectations. A 20 kg loss "should" take 10 months, but realistically plan for 12-13 months.
The Bottom Line
Our calculations show:
- Getting to a healthy BMI takes months, not weeks - Plan for 3-12 months depending on how much you need to lose
- 0.5-0.75 kg per week is the sweet spot - Fast enough to see progress, slow enough to sustain
- Diet matters more than exercise - A 500-calorie food cut beats 45 minutes of running
- The maths is simple - 550 daily deficit = 0.5 kg/week, every time
Stop looking for shortcuts. Use the calculators, know your numbers, and commit to a timeline that actually works.
Run your own numbers:
- BMI Calculator - Find your healthy weight target
- Weight Loss Calculator - Calculate your timeline
- Calories Burned Calculator - See the effort exercise requires