Mealiv
Weight Loss Calculator
Estimate how long it could take to reach your target weight, and what you would need to eat to get there.
Last updated
Choose a pace and this calculator estimates your daily calorie target, your weekly progress and a projected goal date — then shows you how the other two paces compare, side by side.
It is an estimate. Real weight loss is never a straight line, and the sections below explain why, and what to do when the scales stall.
Your estimated plan
What if you chose a different pace?
Switching the pace above updates every figure on this page, so you can see the trade-off between speed and how liveable the target is before committing to one.
Projected timeline
This assumes consistent eating and activity. Real progress includes weeks where the scales stay flat or rise — that is normal, not failure.
Build my meal planWhat is a healthy rate of weight loss?
Slower than most people want, and that is the useful finding rather than a disappointing one.
Around 0.5 kg a week suits most adults. A moderate deficit preserves more muscle, leaves room to actually meet your protein and micronutrient needs, and — the part that decides outcomes — is a change you can still be making in six months.
Your own rate will vary with starting weight, activity, age, medication, health conditions, muscle mass, sleep and diet quality. Heavier people generally lose faster at the start, and everyone slows down as they get lighter.
How the calculator works
Three steps.
First it estimates your basal metabolic rate from your age, sex, height and weight using the Mifflin-St Jeor equation — the same calculation behind our BMR calculator.
Then it applies your activity level to reach maintenance calories, which is what the TDEE calculator works out in more depth.
Finally it subtracts a deficit sized to your chosen pace. At 7,700 kcal per kilogram of body fat, losing 0.5 kg a week needs a deficit of about 550 kcal a day. Divide the weight you want to lose by the weekly rate, and you have a projected date.
All of which assumes your intake and activity stay broadly consistent. They will not, entirely — which is why the date is a projection, not an appointment.
Why weight loss slows down
Almost everyone hits this around month three, and almost everyone reads it as failure. It is arithmetic.
As you get lighter, your body costs less to run. Your BMR falls, your daily expenditure falls with it, and the calorie target you set at the start produces a smaller and smaller deficit until it produces none at all.
Nothing has broken. The plan was correct for a heavier person. Recalculate every few kilograms — and in Mealiv, targets update as your logged weight changes so the plan keeps pace with you.
Weight loss is never a straight line
The timeline above draws a neat diagonal. Your actual chart will not look like that.
Daily weight swings with water retention, glycogen, salt, hormones and simply what is currently in your digestive system — and those swings are routinely larger than a week of genuine fat loss. You can be in a real deficit and see the scales rise for a fortnight.
Weigh once or twice a week under the same conditions and judge the trend across three or four weeks. Reacting to a single morning is the most common way people talk themselves out of a plan that is working.
How to actually reach the target
The calorie number is the easy part. These are what decide whether you get there:
- Eat enough protein. It protects muscle in a deficit and keeps you fuller. Set a figure with the protein calculator.
- Include fibre. Vegetables, wholegrains and pulses make the same calories go much further against hunger.
- Strength train. The clearest way to make sure what you lose is fat rather than muscle.
- Move daily. General activity contributes more than most people expect, often more than the training itself.
- Sleep. Short sleep raises appetite and makes every other decision harder.
- Plan meals. Deciding at 6pm while hungry is where most plans actually fail.
Should you exercise more or eat less?
Both create a deficit, but they are not equally easy.
Offsetting a 250-calorie snack takes 25 to 40 minutes of running. Not eating it takes none. That is not an argument against exercise — which protects muscle, improves fitness and makes the deficit easier to hold — but for most people diet is the larger lever.
The calories burned calculator shows what activity actually contributes, if you want to see the arithmetic yourself.
What happens when you get there?
The bit almost nobody plans for, and where a lot of progress is lost.
Reaching your target means your deficit has done its job and should now stop. Maintenance is a different number and a different skill: increasing food gradually rather than all at once, keeping the habits that got you here, and continuing to weigh occasionally so a drift is caught at 2kg rather than 10.
Mealiv recalculates maintenance for your new weight and keeps planning against it, which turns the end of a diet into a change of target rather than a stop.
From a date to a plan
A goal date is motivating for about a week. What gets anyone to it is knowing what to eat on an ordinary Tuesday.
Mealiv builds meal plans around the calorie target this page produced, sets your protein alongside it, tracks what you actually eat, watches fibre and micronutrients so a deficit does not become a poor diet, and adjusts the target as your weight changes.
Turn the number into macros with the macro calculator, or go straight to a personalised meal plan.
How this is calculated
BMR comes from the Mifflin-St Jeor equation, multiplied by an activity factor between 1.2 and 1.9 to give maintenance calories. The deficit is derived from a single constant of 7,700 kcal per kilogram of body fat, so 0.25, 0.5 and 0.75 kg a week correspond to daily deficits of roughly 275, 550 and 825 kcal. Time to goal is the weight to lose divided by the weekly rate, projected forward from today. Suggested intake is held at a 1,200 kcal floor, and the page says when that floor has been applied. The projection assumes constant intake and activity and does not model the fall in maintenance calories as weight decreases — which is why recalculating every few kilograms is recommended rather than optional. General estimates for healthy adults; not a medical assessment.
weeks = (current − target) ÷ weekly rate
Sources
Frequently asked questions
How accurate is this weight loss calculator?
It is an estimate from established equations and the pace you choose, and it assumes your intake and activity stay broadly consistent. Treat the goal date as a projection rather than an appointment.
How long does it take to lose a stone?
At around 0.5 kg a week, one stone (6.35 kg) takes roughly 13 weeks. At a gentler 0.25 kg a week it is closer to 25. Your own figure depends on your maintenance calories and the deficit you can actually sustain.
How long does it take to lose 10 kg?
Roughly 20 weeks at 0.5 kg a week, or about 40 at a gentler pace. Enter your details above for a figure based on your own maintenance rather than an average.
Is losing weight quickly better?
No. Faster loss costs more muscle, makes nutrition harder, and is considerably more likely to be regained. The pace you can hold for six months beats the one that looks best after two weeks.
Why has my weight stopped changing?
Usually because your maintenance has fallen as you got lighter, so the original deficit has shrunk. Water retention can also hide real fat loss for weeks. Recalculate, and look at three or four weeks of data before changing anything.
Can I lose weight without exercise?
Yes — the deficit is what matters, and diet is the bigger lever for most people. Exercise makes the deficit easier to hold and protects muscle while you lose fat, which changes what you end up looking like.
Should I eat back exercise calories?
Generally not in full, particularly if the activity level you selected already covers your usual training — otherwise it gets counted twice. Estimates also tend to run high.
How often should I weigh myself?
Once or twice a week, same conditions each time. Daily weighing mostly measures water, and reacting to it is how good plans get abandoned.
Does muscle weigh more than fat?
A kilogram of each weighs a kilogram. Muscle is denser, so it takes less space — which is why measurements and how clothes fit can improve while the scales sit still.
Can Mealiv adjust my plan automatically?
Yes. As your logged weight changes, Mealiv updates the calorie target, protein goal and meal plans, which is what stops a plan built for a heavier version of you quietly stalling.
Turn the date into a plan
Calculate your target, then let Mealiv build the meals around it and adjust as your weight changes.
Create my meal planImportant information
These are general estimates for healthy adults and are not medical advice or a treatment plan. The calculator cannot judge whether a target weight or rate of loss is appropriate for you. Speak with a GP, registered dietitian or other qualified healthcare professional before starting a weight-loss plan if you have a health condition, take medication affecting weight or appetite, are pregnant or breastfeeding, are under 18, or have any history of disordered eating. If tracking weight is affecting your wellbeing, Beat runs a free confidential helpline.