Weight loss comes down to eating fewer calories than you burn. The practical version: estimate your daily burn (TDEE), subtract a moderate amount, and aim for steady, sustainable loss rather than a crash.
Step 1 — find your maintenance calories
Your TDEE (Total Daily Energy Expenditure) is roughly how many calories you burn in a day, including activity. Eating at your TDEE keeps your weight stable. Our calculator estimates it from your age, sex, height, weight and activity level.
Step 2 — apply a sensible deficit
To lose weight, eat below your TDEE. A pound of fat is about 3,500 calories, so a daily deficit of 500 calories points toward roughly a pound a week.
| Daily deficit | Approx. weekly loss | Best for |
|---|---|---|
| 250 cal | ~0.5 lb | Slow, very sustainable |
| 500 cal | ~1 lb | Most people |
| 750–1000 cal | ~1.5–2 lb | Higher starting weight, with care |
Step 3 — keep protein up
In a deficit, adequate protein helps preserve muscle so most of what you lose is fat. It's also the most filling macronutrient, which makes the deficit easier to stick to. See setting protein targets (a macro calculator is coming soon).
Step 4 — adjust with reality, not the formula
The calculator gives a starting estimate. Track your weight trend over 2–3 weeks; if it's not moving, nudge calories down or activity up. Bodies differ, and the scale is the real feedback.
What the number is, and what it isn't
Every calorie calculator on the internet, including ours, runs a decades-old equation over your age, sex, height, weight and a rough activity multiplier. That's it. It has never met you. Two people who enter identical numbers can genuinely burn a few hundred calories a day apart, because body composition, how much you fidget, how much you sleep, medications, and how physical your job really is all sit outside the formula.
So treat the output as a starting hypothesis, not a verdict. It's a sensible place to begin measuring from, and the measuring is what actually tells you the truth.
Six beliefs that quietly sabotage the number
Most people who say "calorie counting didn't work for me" ran into one of these rather than into a broken metabolism.
"3,500 calories per pound is a hard rule"
It's a useful rule of thumb, not a law. It comes from the rough energy content of stored fat and assumes everything else about you holds still. It doesn't. As you get lighter you burn less simply because there's less of you to move and maintain, so the same calorie target that produced a pound a week in month one produces less by month four. That isn't failure — it's arithmetic, and it's the reason targets need periodic revisiting.
"My tracking is accurate"
Packaged food labels are allowed a margin of error. Restaurant portions vary by whoever's on shift. Cooking oil, dressings, sauces, milk in coffee and "a handful of" anything are the usual leaks, and they're easy to underestimate by several hundred calories a day without noticing. Weighing food for a single ordinary week — not forever, just once, as a calibration exercise — is usually more revealing than any calculator.
"The scale measures fat"
The scale measures everything: fat, muscle, bone, food still being digested, and above all water. A salty meal, a hard workout, a change in carbohydrate intake, constipation or the menstrual cycle can each move it by several pounds in either direction, and none of that is fat. Weigh under the same conditions — same time of day, same circumstances — and read the two-week trend line, not any individual morning.
"Bigger deficit, better result"
Aggressive deficits win the first fortnight and lose the year. They're harder to adhere to, they tend to cost more muscle alongside fat, and they set up the all-or-nothing cycle where one bad day turns into an abandoned month. The deficit you can actually maintain for six months beats a steeper one you quit in three weeks — which is why the moderate row in the table above suits most people.
"Exercise calories are money in the bank"
Wearables and cardio machines tend to be optimistic about how much you burned, and people tend to be optimistic about how much they can therefore eat. There's also a subtler effect: after hard training many people move less for the rest of the day without realising it, which quietly claws back part of the burn. Exercise is worth doing for strength, cardiovascular health, mood and appetite regulation — just don't budget your food around its estimated calorie figure.
"I have to hit the number exactly, every day"
Your body doesn't reconcile its books at midnight. What matters is the average across the week. A planned bigger day at a dinner or a birthday, offset over the following days, is a perfectly ordinary part of a working plan — and treating it as a failure is what turns one meal into a lost month.
How to tell whether your target is actually working
Give any target a fair trial before changing it. A reasonable approach:
- Hold the target steady for two to three full weeks. One week is mostly water-weight noise.
- Weigh under consistent conditions and compare weekly averages rather than single readings.
- If the average hasn't moved at all across that window, adjust in small steps — a modest reduction in calories or a modest increase in daily movement — rather than slashing hundreds at once.
- If the average is falling faster than you intended, or you feel persistently exhausted, cold, or preoccupied with food, that's a signal to eat more, not to push harder.
When the plateau isn't a plateau
Genuine stalls do happen, but a fortnight of a flat scale usually isn't one. Water retention from new training, a change in sodium or fibre, and simple day-to-day fluctuation routinely mask several weeks of real fat loss before the scale catches up in one sudden drop. Before assuming your metabolism has stopped, check the boring explanations first: has intake crept up, has portion size drifted, has non-exercise movement dropped because it got cold or busy?
Where a calculator isn't the right starting point
Generic formulas assume a healthy adult with no complicating factors, and they aren't appropriate for everyone. If you're pregnant or breastfeeding, under 18, over 65, an athlete in heavy training, living with diabetes, thyroid or kidney conditions, taking medication that affects weight or appetite, or you have any history of disordered eating, please work with a doctor or a registered dietitian rather than an online estimate. The same applies if you want to lose a large amount of weight, or if weight loss is happening without you trying.
Nothing here is a diet prescription or medical advice — it's general education about how the numbers behave. A qualified professional can account for the parts of your situation that no formula can see.
Find your starting target with the calorie calculator, then refine from there.
This article is general information, not financial, tax, or medical advice. See our disclaimer.