TDEE and BMR calculator: estimate maintenance, then check it

BMR is what your body burns at rest; TDEE is what it burns across a whole day. This calculator shows both, then gives you a second way to check maintenance from what you ate and what the scale did.

For a 35-year-old woman at 170 cm and 80 kg, the resting estimate is about 1,527 kcal. Multiply by 1.45 and maintenance comes out at about 2,213 kcal/day. Drop activity to 1.2 and it falls to about 1,832. The dropdown deserves more of your attention than the last decimal.

What BMR and TDEE include

BMR is the energy you need at rest. This tool estimates it with Mifflin–St Jeor, an equation built for resting energy expenditure and the one most calculators use. A laboratory measures it under stricter conditions than any formula can assume. Mifflin et al.

TDEE adds movement, exercise and the energy spent digesting food. Multiplying the resting estimate by an activity factor gets you close to that total in one step; it does not measure any of the parts.

The calculator uses HeyCoach's three factors: 1.2, 1.45 and 1.65. Three options keep the choice simple. If your weeks look nothing like each other, one category will fit loosely, and the two-week check below matters more.

Choose activity from the ordinary week

Count the whole week: workday, commute, chores, walking and training together. Someone who lifts three times a week but sits for ten hours a day can burn less than someone who walks an active shift and never sees a gym.

It is tempting to pick the higher multiplier because it buys a bigger food budget. Start with the honest one and let the scale argue you up.

Watch for double counting, too. If your workouts already pushed you into a higher activity category, adding their full reported calories on top inflates the estimate. Our TDEE explainer covers how much uncertainty to expect.

The two-week correction

The expandable section uses this rough energy-balance check:

Observed TDEE ≈ average intake + (starting weight − ending weight) × 7,700 ÷ 14

Enter two smoothed weights 14 days apart and your average intake over the same two weeks. Losing weight pushes the estimate above what you ate; gaining pulls it below.

It is a rough check, not a metabolic lab. The 7,700 conversion is fixed, the window is short, and a shift in water can swamp the real change in tissue. Use it to ask whether your starting estimate is close, not to forecast months ahead.

Before you stretch this arithmetic across months, read why the 3,500-calorie rule breaks over time.

A worked correction

Say your log shows:

• Average intake: 2,000 kcal/day.
• Starting trend weight: 80.0 kg.
• Trend weight 14 days later: 79.5 kg.
• Change: 0.5 kg down.

The gap works out at 0.5 × 7,700 ÷ 14, or 275 kcal/day. Add it to intake and your observed maintenance is about 2,275 kcal/day.

That sits close to the formula's 2,213. Leave the 62-kcal gap alone; neither number is exact enough to argue over. If the two disagreed by hundreds of calories, look at missing meals, the activity setting and water before anything else.

When to collect more data

A new strength routine, travel, illness, a change in carbohydrate intake, constipation and the menstrual cycle can all bend a two-week comparison. When one of those is in play, give it longer, or compare weights at the same point in the cycle.

Missing meals are the other problem. Leave 300 kcal/day out of the log while the scale holds steady and the tool will put your maintenance roughly 300 too low. It can only work with what you gave it.

Run the plateau checklist before you change your intake. If the estimate lands somewhere implausible, the calculator asks you to check the inputs rather than hand you the number.

FAQ

Should I eat my BMR?

No. BMR is what you burn lying still, and your day burns more than that. Your intake comes from TDEE, your goal and your circumstances, not from the resting number.

Does losing half a kilogram prove a 3,850-calorie deficit?

No. The scale moves with water and what is in your gut, not only fat. The conversion is a rough check that gets better the longer and steadier the trend.

Will HeyCoach automatically run this correction?

Not on its own yet. Log meals and weigh-ins, then ask the coach how the week went: it reads the trend back to you, average intake against target and what the scale did over 7, 14 or 30 days, and it changes your calorie target when you ask.

The easy way to do this

A maintenance estimate is only worth what you can check it against, and HeyCoach keeps the evidence in one WhatsApp thread with no app to download. A photo or one line logs each meal, a reply fixes an estimate even days later, and your weigh-ins sit in the same conversation. After two ordinary weeks, ask how it went and the coach reads the trend back to you.