TDEE Calculator

Your TDEE is BMR multiplied by an activity factor. The Mifflin-St Jeor BMR formula in metric units: men: BMR = (10 × kg) + (6.25 × cm) − (5 × age) + 5; women: BMR = (10 × kg) + (6.25 × cm) − (5 × age) − 161. In imperial: convert pounds to kg by dividing by 2.205, and inches to cm by multiplying by 2.54, then plug in. A 30-year-old man at 80 kg and 180 cm has a BMR of 1,806 kcal. The activity multiplier ranges from 1.2 (sedentary, desk job, no exercise) through 1.375 (light exercise 1-3 days/week), 1.55 (moderate 3-5 days), 1.725 (active 6-7 days), to 1.9 (very active, intense daily training or physical labour). The same man at moderate activity has a TDEE of 1,806 × 1.55 = 2,799 kcal. To convert calories to kilojoules — required if you're reading Australian or New Zealand food labels — multiply by 4.184. So 2,799 kcal becomes 11,710 kJ. Why Mifflin-St Jeor over the older Harris-Benedict? Mifflin-St Jeor was validated against a leaner, more contemporary population in 1990 and reduces the systematic 5-10% overestimation that Harris-Benedict produces in modern measurements.

The USDA Dietary Guidelines for Americans 2020-2025 sets calorie reference levels by age, sex, and activity. For sedentary adults: women aged 19-30 need ~2,000 kcal, men aged 19-30 need ~2,400 kcal; numbers drop with age and rise with activity. These are the figures behind the FDA-mandated calorie disclosures on chain restaurant menus (the line that says 'a 2,000 calorie diet is used as a basis for daily nutrition advice'). The American sedentary baseline is the dominant TDEE story for the US: roughly 60% of adults work desk-based jobs, the average American walks under 4,500 steps per day, and total NEAT (non-exercise activity thermogenesis) is among the lowest of high-income countries. This means the activity multiplier most US users should pick honestly is 1.2 (sedentary) or 1.375 (light), not 1.55 (moderate) — and overestimating activity is the single most common reason a calorie deficit fails to produce weight loss. For unit input: most US users prefer pounds and feet/inches; our calculator handles both, converting internally to metric for the formula.

The NHS UK reference daily intake is 2,000 kcal for women and 2,500 kcal for men — the figures used on traffic-light food labels and in NHS healthy-eating campaigns. Like the US baseline, these assume moderate activity and are population averages, not personal targets. Where the UK diverges meaningfully is alcohol. UK adults who drink regularly underestimate their intake by 200-400 kcal per day on average, and unlike the US no calorie figure is required on alcoholic drinks under current law. A pint of strong lager (5.6% ABV) is around 240 kcal, a 175 ml glass of wine is 160 kcal, and a double gin and tonic is 170 kcal. Two pints on a Friday adds nearly 500 kcal that's invisible in most food-tracking. NHS Eatwell Guide recommends keeping alcohol below 14 units per week (~6 medium glasses of wine or 6 pints of medium-strength beer) — for TDEE planning, treat alcohol calories as additive on top of food intake, since alcohol is preferentially metabolised before fat. UK food labels show kcal/100g and per portion, with 'reference intake' percentages based on the 2,000 kcal woman baseline.

Health Canada's Nutrition Facts panel uses 2,000 kcal as the reference daily intake — identical to the US format. The 2019 Canada Food Guide moved away from explicit calorie counting toward portion proportions on a plate (½ vegetables and fruit, ¼ whole grains, ¼ protein), but the underlying calorie reference remains 2,000 kcal for the adult average. Imported and bilingual-export packaged food sold in Canada commonly shows kJ alongside kcal, especially products dual-labelled for European or Asian markets — useful if you're switching between Canadian and European brands. Cold-climate winter NEAT is a small but real factor: studies show a 50-150 kcal/day increase in BMR during sustained cold exposure due to non-shivering thermogenesis. For most urban Canadians who move between heated indoor spaces, this effect is negligible; for outdoor workers, snow-shovellers, or winter-sport enthusiasts in BC, Alberta, or northern Ontario, it can be a meaningful add to the activity multiplier — typically by stepping up one tier (sedentary to light, light to moderate) during the winter months.

Australia and New Zealand are the kJ outliers of the English-speaking world. Food labels list kilojoules first and prominently, with calories in smaller text or omitted entirely. The Australian Government Dietary Guidelines reference adult average intake is 8,700 kJ per day — equivalent to 2,079 kcal — used on packaged-food '%DI' (percent daily intake) labels and on the '8700 kJ' consumer-education campaign. Reading an Australian food label requires kJ comfort: a Tim Tam at 410 kJ becomes 98 kcal, a 600 ml bottle of full-cream milk at 1,690 kJ is 404 kcal, a typical fast-food meal at 4,000 kJ is 956 kcal — almost half the daily 8,700 kJ reference. Convert from your TDEE in kcal to kJ by multiplying by 4.184: a 2,500 kcal TDEE = 10,460 kJ. New Zealand uses identical labelling under joint food-standards regulation. Australian penalty-rate hospitality and the higher cost of dining out tends to push more home-cooking, which makes calorie tracking via labels more practical than it is in markets dominated by unlabelled restaurant meals. Use the calculator above in kcal then convert if your tracking app or food packet runs in kJ.

The single biggest source of TDEE error isn't the BMR formula; it's the activity multiplier. Most people who pick 'moderate' (1.55) for 3-5 workouts per week end up in a calorie surplus they didn't intend, because outside the gym they're sitting at a desk, commuting in a car, and walking under 5,000 steps. Honest activity assessment looks like this: if your job is desk-based AND you don't deliberately walk to commute, start with sedentary (1.2). If you do 3-4 strength sessions of 45-60 minutes per week and otherwise sit, that's still light (1.375), not moderate. Moderate (1.55) requires daily intentional movement — gym 4-5x plus walking 8,000+ steps, or a job that has you on your feet most of the day. Active (1.725) is daily training plus a physical job. Very active (1.9) is reserved for endurance athletes in heavy training blocks or labourers with multi-hour intense physical work. NEAT (non-exercise activity thermogenesis) — fidgeting, standing, walking around — varies more between individuals than scheduled exercise does, with research showing a 2,000 kcal/day spread between low and high NEAT in similar-bodied people. If your weight isn't changing on the calculated TDEE, the multiplier is wrong; drop one tier and re-track for two weeks before changing food intake.

Once TDEE is dialled in, goal calories follow simple rules. Fat loss: subtract 500 kcal/day for ~0.5 kg (1 lb) per week loss; subtract 750 kcal for aggressive ~0.75 kg/week (only sustainable for 8-12 weeks); never go below 1,200 kcal (women) or 1,500 kcal (men) without medical supervision. Maintenance: eat at TDEE; useful for diet breaks, refeeds, or after reaching goal weight to consolidate. Lean bulking: add 250-500 kcal/day for ~0.25-0.5 kg/week gain, paired with progressive-overload strength training and 1.6-2.2 g protein per kg bodyweight; faster surplus produces more fat gain per kg of muscle. Body recomposition (losing fat while gaining muscle simultaneously) works at maintenance or a small deficit, but only for: lifters in their first 12-18 months of training, those returning after a long break (muscle memory), people with high body fat (~25%+ for men, 30%+ for women), or anyone with very high protein intake. Recompose progress is invisible on the scale and slow; judge by photos, tape measurements, and strength gains. Whichever phase you're in, recalculate TDEE after every 5-10 kg of weight change — TDEE drops as you lose mass, so the deficit that worked at 80 kg is closer to maintenance at 70 kg.

Long calorie deficits don't proceed in a straight line. After 8-16 weeks of consistent dieting, weight loss slows or stops even with no change in food intake. This isn't 'cheating' or measurement error in most cases — it's metabolic adaptation, also called adaptive thermogenesis. The body responds to sustained energy restriction by reducing BMR by 5-15% beyond what weight loss alone predicts, decreasing NEAT (you fidget less, walk less, stand less without consciously realising it), and lowering the energy cost of exercise (workouts at the same prescribed intensity feel harder but burn fewer calories). Hormonally, leptin drops, thyroid hormones (T3, T4) decrease, and cortisol rises — all signals that say 'food is scarce, conserve energy'. The fix is not to push the deficit deeper, which accelerates these adaptations and risks muscle loss. The fix is a planned diet break of 1-2 weeks at maintenance calories — enough food to restore leptin, thyroid markers, and training quality — before resuming the cut. Best practice for cuts longer than 8 weeks: alternate 6-8 week cutting blocks with 1-2 week maintenance phases. After reaching goal weight, transition through a 4-8 week 'reverse diet' (gradually adding 100 kcal/week back to estimated maintenance) rather than jumping straight from deficit to surplus, to give metabolism time to recover before the next bulk or maintenance phase.