Choose enough time
CDC and NHS guidance commonly describes about 0.5–1 kg (1–2 lb) per week as gradual loss. A longer timeline can make the required daily change more manageable.
Plan a realistic pace
Weight Loss Calculator
Enter your current weight, target weight and timeframe to estimate the calorie deficit and weekly pace your goal would require.
Goal planner
Calculate your required deficit
For adults · Planning estimate, not a prescription
Private by design. Your measurements and results stay in this browser.
Your goal
Weight and timeframe
Your estimate
Required daily deficit
kcal/day
2,879 kJ/day
Within gradual range
This goal requires an estimated loss of 0.63 kg per week, within the commonly suggested gradual range.
Total weight change
10 kg
Weekly pace
0.63 kg/week
Goal date
—
Weekly energy deficit
4,813 kcal
Gradual target-date range
At 0.5–1 kg per week, this change would take roughly 10–20 weeks.
Estimated maintenance
—
Estimated intake for this plan
Add optional details
No-equipment activity planner
Activities for your 688 kcal daily deficit
min/day
estimated kcal
Selected activities share your calculated deficit equally. Untick anything unsuitable and the remaining times update automatically.
Select at least one suitable activity to build the illustration.
Exercise-only illustration. Times estimate additional energy above rest and are not a workout prescription. A high calculated deficit can require an impractical or unsafe amount of activity.
This is an estimate, not medical advice. Weight change is not linear and the body adapts over time. Do not use this tool if you are under 18, pregnant or breastfeeding, or have an eating disorder without professional guidance.
Read the result well
Turn a number into a workable plan
A calorie deficit is a useful planning estimate, not a daily score to hit perfectly. Weekly trends, sustainable habits and individual health matter more than a single calculated number.
See what exercise alone would require
The activity planner translates the required deficit into approximate daily movement. It can reveal when exercise alone would take an impractical amount of time; food and activity estimates are never exact.
Review the trend
Water and normal daily variation can hide fat loss temporarily. Compare consistent measurements over several weeks, then adjust with professional support if needed.
How the estimate works
Simple planning maths with honest limits
The calculator uses about 7,700 kcal per kilogram (3,500 kcal per pound) to translate a weight goal into an average deficit. This traditional shortcut is useful for comparison, but it cannot model metabolic adaptation.
Get help before using a calorie target if you
- Are under 18, pregnant or breastfeeding.
- Have an eating disorder or a history of disordered eating.
- Use medicines or have a condition that affects weight or appetite.
- Receive a result that feels extreme, distressing or difficult to sustain.
Calculation summary
- 1
Weight to lose = current weight − target weight.
- 2
Total energy equivalent = kilograms to lose × 7,700 kcal.
- 3
Daily deficit = total energy equivalent ÷ days to goal.
- 4
Estimated intake = maintenance calories − daily deficit, when optional details are supplied.
Guidance and modelling context: CDC gradual weight loss, NHS weight management, NIH Body Weight Planner and 2024 Adult Compendium activity values.
Weight loss planning questions
Weight Loss Calculator FAQ
How does this weight loss calculator work?
It subtracts target weight from current weight, divides the change across the selected time, and uses an approximate energy equivalent of 3,500 kcal per pound, or about 7,700 kcal per kilogram. Real weight change is not perfectly linear, so treat the result as a planning estimate.
What is a reasonable weekly weight loss goal?
The CDC and NHS describe gradual weight loss of about 1 to 2 pounds, or 0.5 to 1 kilogram, per week as a suitable general aim for many adults. Individual needs can differ.
What is a calorie deficit?
A calorie deficit means using more energy than you consume. It can come from eating fewer calories, increasing physical activity, or a combination of both.
Is a 500-calorie daily deficit enough?
Using the traditional energy-equivalent estimate, 500 kcal per day corresponds to about 1 pound or 0.45 kilogram per week. Actual progress varies because metabolism, activity, water and appetite change over time.
Why might actual weight loss differ from the estimate?
The body needs fewer calories at a lower weight, and metabolism, appetite, activity, medicines, health conditions, fluid balance and measurement error can all change the result. The calculator therefore shows an estimate rather than a guarantee.
How does the no-equipment activity planner work?
The planner divides the calculated daily deficit equally across the selected activities. It estimates minutes from current weight and published MET intensity values. Unticking an activity redistributes its share, but the result remains an exercise-only illustration rather than a workout prescription.
How is the optional maintenance-calorie estimate calculated?
It uses the Mifflin–St Jeor resting-energy equation and an activity multiplier. The result is only a starting estimate. If you already know your maintenance intake from reliable tracking or professional advice, you can enter it directly.
Can I use kilograms and kilojoules?
Yes. Metric mode uses kilograms and centimetres. Every calorie-deficit result also includes kilojoules, using 1 kilocalorie equal to 4.184 kilojoules.
Who should ask a healthcare professional before planning weight loss?
People under 18, anyone who is pregnant or breastfeeding, people with an eating disorder or a history of one, and anyone with relevant medical conditions or medicines should seek individual professional advice.
Does Bobek store my weight or personal details?
No. The calculation runs locally in your browser. Bobek does not receive or store the measurements entered into this tool.