Losing 1lb (roughly 0.45kg) a week is one of the most commonly cited weight loss targets, and for good reason – it’s a well-supported, generally sustainable pace for most people. Here’s exactly how to calculate the deficit needed to hit it.
The Underlying Maths
One pound of body fat represents approximately 3,500 kcal. To lose 1lb over a week, you therefore need a cumulative weekly deficit of roughly 3,500 kcal, which works out to:
3,500 ÷ 7 = 500 kcal per day
This is precisely where the widely quoted “500 calorie deficit” recommendation comes from – it’s specifically calibrated to produce around 1lb (or roughly 0.45kg) of weight loss per week on average.
Applying It to Your Own Numbers
Start by calculating your TDEE – your maintenance calorie level. Then subtract 500 kcal:
| TDEE | Calorie Target for 1lb/Week Loss |
|---|---|
| 1,800 kcal | 1,300 kcal |
| 2,200 kcal | 1,700 kcal |
| 2,600 kcal | 2,100 kcal |
Our Calorie Deficit Calculator applies this automatically against your specific TDEE, so you don’t need to do the subtraction by hand each time you recalculate.
Is 1lb a Week the Right Pace for You?
This pace is generally well-suited to a broad range of people, but it’s worth checking it against your own starting point:
- If you have significant weight to lose, a 500 kcal deficit representing 1lb/week may feel relatively gentle, and some people in this position comfortably use a somewhat larger deficit – see our full guide on safe deficit ranges.
- If you’re already close to a healthy weight, a 500 kcal fixed deficit might represent a larger percentage of your TDEE than intended, and a smaller cut may be more appropriate – see the percentage-based approach in our 20% calorie deficit guide.
Why the Real-World Pace Sometimes Differs
The 3,500 kcal per pound rule is a useful planning average, but real-world weight loss doesn’t always match it precisely week to week, for several genuine reasons:
- Water retention fluctuates with sodium, carbohydrate intake, hormones and stress, independent of actual fat loss – see water weight vs fat loss
- As you lose weight, your TDEE gradually decreases, meaning the same fixed 500 kcal deficit represents a slightly bigger percentage cut over time – sometimes accelerating loss slightly, or requiring recalculation to keep pace consistent, as covered in our guide to breaking a weight loss plateau
- Tracking accuracy affects how closely your actual deficit matches your intended one
The most reliable way to check whether you’re genuinely on pace is comparing your weight trend over 3–4 weeks against the roughly 1.8kg (about 4lb) predicted over that period, rather than judging any single week in isolation.
Frequently Asked Questions
Is 1lb a week too slow?
It’s widely regarded as a solid, sustainable pace rather than a slow one – faster rates generally carry a higher risk of muscle loss and are harder to sustain, as covered in our guide on aggressive deficit risks.
Why did I only lose half a pound this week despite a 500 calorie deficit?
Weekly results vary due to water retention, tracking precision and natural biological variation – a single week rarely matches the average precisely, which is why judging progress over 3–4 week windows is more reliable.
Do I need to hit exactly 500 kcal below TDEE every single day?
No – what matters most is your average deficit across the week. Some day-to-day variation, as long as the weekly average roughly matches your target, will still produce close to the expected result.
Should this pace change once I get closer to my goal weight?
Many people find it useful to slow the pace (a smaller deficit) as they approach a healthy weight, since the closer to a lean, healthy body composition someone gets, the more a large deficit risks muscle loss relative to the remaining fat to lose.
Is losing 1lb a week the same experience for everyone?
Not necessarily – the same absolute deficit (500 kcal) represents a bigger proportional cut for someone with a smaller TDEE than for someone with a larger one, which is why some people find a fixed 1lb/week target feels noticeably more restrictive than others do, even at the same weekly loss rate.
How many weeks should I plan for to reach my overall goal at this pace?
Simply divide your total weight loss goal (in pounds) by 1 to estimate the number of weeks needed at this pace, keeping in mind that most diets don’t proceed in a perfectly straight line week to week, so treat this as a rough planning guide rather than a guaranteed schedule.
Does 1lb a week apply the same way to men and women?
The underlying calorie maths (3,500 kcal per pound, 500 kcal per day) applies the same way regardless of sex, though starting TDEE typically differs between men and women, which affects what percentage of total calories a 500 kcal deficit represents for each person individually.
Metric Versus Imperial: Working in Kilograms Instead
Since the UK commonly uses both imperial and metric units for body weight, it’s worth clarifying the metric equivalent: 1lb is approximately 0.45kg, and the same 500 kcal daily deficit applies whether you’re tracking your progress in pounds or kilograms – the underlying calorie maths doesn’t change based on which unit you personally prefer to weigh yourself in. Our Calorie Deficit Calculator and TDEE Calculator both accept either unit, so use whichever you find easier to track consistently over time.
What This Pace Looks Like Over a Longer Timeline
To put the 1lb/week pace into a longer-term perspective:
| Timeframe | Approx. Total Loss |
|---|---|
| 4 weeks | ~4lb (1.8kg) |
| 12 weeks (3 months) | ~12lb (5.4kg) |
| 24 weeks (6 months) | ~24lb (10.9kg) |
Seen this way, a “modest” weekly pace compounds into a substantial result over a realistic timeframe, which is exactly why this rate is so widely recommended: it’s slow enough to be genuinely sustainable, hunger and energy permitting, while still delivering meaningful, visible progress well within a typical diet timeline of a few months.