Calorie calculator

what is a calorie deficit?

A calorie deficit is eating fewer calories per day than your body burns. Sustain one and your body draws the difference from stored fat (and, partly, from muscle and water) — so bodyweight drops. A calorie surplus is the opposite: eat more than you burn and the excess is stored, mostly as fat with some lean mass alongside if you train.

The size of the deficit (or surplus) sets the rate. The constant most consumer calculators use is 7700 kcal per kilogram of bodyweight (Wishnofsky 1958, Am J Clin Nutr 6:542–6). Knock 550 kcal off your maintenance every day for a week and you'll drop about 0.5 kg — provided you actually hit the target.

fast vs steady weight loss

Steady loss (~0.5 kg/wk) is what almost every clinical guideline recommends. It's slow enough to preserve lean mass with adequate protein, sustainable for 12+ weeks, and rarely triggers the metabolic adaptation that sabotages aggressive cuts.

Fast loss (~1 kg/wk) works for short blocks (4–8 weeks) when the deficit is large but the cut has a hard end-date — pre-event, post-holiday reset, weight-class meet. Pair with protein at 1.8–2.2 g/kg (Helms et al. 2014, PMID 24864135) to limit lean-mass loss, and plan a refeed week back at maintenance every 4 weeks.

This calculator does not display weight-loss targets below 1200 kcal/day. That display limit is not a determination of a safe or adequate intake for you. Individual needs can be substantially higher, particularly with training; avoid treating the minimum as a target.

how many calories to lose weight?

Find your TDEE on this page, then subtract 550 kcal/day for steady loss or 770 kcal/day for fast loss (the defaults — the rate selector adjusts them). The five rows above are the same math at the selected rates — pick the row that matches what you actually want.

A worked example: a 35-year-old, 180 cm, 90 kg male at moderately active (1.55) has a TDEE of about 2725 kcal/day. Steady loss target = 2225 kcal/day, projecting ~0.45 kg/wk. Fast loss target = 1725 kcal/day, projecting ~0.91 kg/wk. The same body at sedentary (1.20) drops to TDEE 2110 kcal/day — pick the activity band honestly or the prediction is wrong before you start.

calorie targets for women vs men

Mifflin-St Jeor uses the same equation structure with constant terms of +5 and −161, a difference of 166 kcal/day. For example, at an activity factor of 1.55, a 60 kg, 165 cm, 30-year-old female has an estimated TDEE of about 2050 kcal/day; an 80 kg, 178 cm, 30-year-old male about 2740 kcal/day. These are formula examples, not prescribed intakes. The same calorie deficit represents a larger percentage of a smaller estimated daily requirement.

should I track calories every day?

Not necessarily. The evidence on tracking is split: a weekly average within 5–10% of the target is what actually moves bodyweight; daily exactness matters less than people fear. What does help is tracking for the first 14 days of any new target so you calibrate portion sizes against the number, then loosening to flexible/intuitive tracking once you've internalised what 2200 kcal/day looks like on your plate.

Re-run this calculator every 4–6 weeks or after a bodyweight shift greater than 3 kg. BMR scales linearly with kg in Mifflin — losing 5 kg drops your maintenance by ~50 kcal/day, and the calorie target should follow.

why am I not losing weight at my calorie target?

Two honest answers, in order of likelihood:

First, unmeasured calories. Cooking oils, sauces, drinks (including alcohol), bites-and-tastes while preparing food — these routinely add 200–500 kcal/day that don't show up in a tracker. Two weeks of weighing everything, including the oil in the pan, usually closes the gap.

Second, activity drift. Most people underestimate sedentary days and overestimate training-heavy days. If you eat at "moderately active" (1.55) but your weekly average is closer to "lightly active" (1.375), that's a 250–400 kcal/day over-prediction. Track step-count or actually clock training hours for a week before re-picking the activity band.

Real adaptive thermogenesis exists (Rosenbaum & Leibel 2010, Int J Obes 34:S47–55, PMID 20935667), but it's typically 50–100 kcal/day below the linear prediction after a long cut — not enough to explain a complete stall on its own.

method notes

Energy intake, protein and resistance training all matter when assessing body-composition changes. Longland et al. (2016, trial) compared two protein intakes during a controlled energy deficit and intense exercise. Roth et al. (2022, review) examined training volume during restriction. Neither establishes a universal deficit or set count that guarantees muscle retention. For a maintenance estimate, see the TDEE calculator.

frequently asked

How many calories should I eat to lose 1 kg per week?

About 1000 kcal/day below your TDEE — the "fast loss" row above. A 7700 kcal/kg approximation × 1 kg/wk = 7700 kcal/wk ÷ 7 days = ~1100 kcal/day deficit, which the table rounds to 1000 kcal/day. Most people cannot sustain that pace beyond 4–8 weeks before adherence breaks down or strength craters; steady loss at 0.5 kg/wk is the safer default.

What is a safe calorie deficit?

There is no universal calorie deficit that preserves strength or is appropriate for everyone. The options here show arithmetic scenarios from estimated TDEE, not an assessment of energy availability or health. The 1200 kcal display limit does not mean that this intake is adequate. A qualified dietitian can help individualize a plan when training demands or health considerations require it.

How accurate is this calorie calculator?

This calculator estimates daily needs; it does not measure them. Frankenfield, Roth-Yousey & Compher (2005, systematic review) evaluated resting-metabolism equations, not the accuracy of this full daily-calorie calculator. Activity estimates add another source of uncertainty. Use trends over time to evaluate the starting estimate.

Calorie calculator vs TDEE calculator — what's the difference?

TDEE is the input — your maintenance number — and the TDEE calculator is the place to find it. This page takes that TDEE and turns it into goal targets: how many calories to eat per day to lose, maintain, or gain at a chosen rate. Same Mifflin-St Jeor backbone, different framing of the output.

How fast can I gain weight without getting fat?

No fixed gain rate guarantees muscle without fat gain. Iraki et al. (2019, narrative review) discusses approximately 0.25–0.5 % of bodyweight per week for novice/intermediate bodybuilders and more conservative gains for advanced athletes. That is a bodyweight percentage, not a universal 0.25 kg weekly threshold. The calculator rows are scenarios, not predictions of muscle gained.

Do calorie targets work for women?

The calculator uses the same equation structure and scenario arithmetic with different regression constants. Individual requirements still depend on more than the sex category. An output or a displayed minimum should not be taken as a reason to cut food further or add exercise to compensate.