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Calorie Calculator

Estimate the calories you burn a day and what to eat for your goal

Units

Sex

Age

Enter an age (10-100)

Height

Enter a valid height

Weight

Enter a valid weight

Activity Level

BMR Formula

Enter body fat percentage (2-70)

Goal

Daily Calories

Maintenance (TDEE)

BMR

Daily Adjustment

Weekly Change

Calorie Calculator — Complete Guide

Weight is governed by a simple balance: calories in versus calories out. Everything else — meal timing, food type, macros — matters mostly through how it affects that balance. This calculator estimates the "out" side for your body.

What this calculator does

Using your sex, age, height, weight and activity level, it estimates your basal metabolic rate (BMR), your total daily energy expenditure (TDEE), and a daily calorie target based on whether you want to lose, keep or gain weight.

The formula

BMR (men) = 10w + 6.25h − 5a + 5
BMR (women) = 10w + 6.25h − 5a − 161
TDEE = BMR × activity factor

This is the Mifflin-St Jeor equation, with weight in kilograms and height in centimetres. Activity factors run from 1.2 (sedentary) to 1.9 (very active).

A worked example

A 30-year-old woman weighing 70 kg at 175 cm: BMR = 700 + 1,093.75 − 150 − 161 = 1,482.75. At a moderate activity factor of 1.55, TDEE is about 2,298 calories. A 500-calorie deficit for weight loss gives a target of roughly 1,798 calories a day — about 0.45 kg (1 lb) a week.

Goal	Daily adjustment	Weekly change
Lose weight	−500	≈ −0.45 kg
Maintain	0	0
Gain weight	+500	≈ +0.45 kg

Where the estimate goes wrong

Activity factors are coarse. Five broad bands cannot capture a week of mixed training and desk work.
Metabolism adapts. Eat less for long enough and TDEE falls too, which is why weight loss slows.
TDEE falls with body weight. As you lose mass, maintenance drops; the target has to be recalculated.
Individual variation. Two people with identical stats can differ by 200-300 calories a day.

Treat the number as a starting point, then adjust by what the scale actually does over two to three weeks.

每日热量计算器完整使用指南

体重由一笔简单的账决定：摄入的热量 vs 消耗的热量。其他因素 —— 进食时间、食物种类、营养素配比 —— 大多是通过影响这笔账来起作用。这个计算器算的是「消耗」这一端。

这个计算器能做什么

根据性别、年龄、身高、体重和活动水平，估算你的基础代谢率（BMR）、每日总消耗（TDEE），以及按「减重 / 维持 / 增重」目标给出的每日热量摄入建议。

计算公式

BMR（男）= 10w + 6.25h − 5a + 5
BMR（女）= 10w + 6.25h − 5a − 161
TDEE = BMR × 活动系数

这就是 Mifflin-St Jeor 公式，其中体重单位为公斤、身高单位为厘米。活动系数从 1.2（久坐）到 1.9（非常活跃）。

算例演示

一位 30 岁女性，体重 70 公斤、身高 175 厘米：BMR = 700 + 1093.75 − 150 − 161 = 1482.75。按中等活动系数 1.55 计算，TDEE 约为 2298 千卡。若以 500 千卡缺口减重，目标约为每天 1798 千卡 —— 每周约减 0.45 公斤。

目标	每日调整量	每周变化
减重	−500	约 −0.45 公斤
维持	0	0
增重	+500	约 +0.45 公斤

估算会在哪里失准

活动系数偏粗。 五档划分无法刻画「混合训练 + 坐办公室」的一周。
代谢会适应。 长期少吃，TDEE 也会下降，这正是减重后期变慢的原因。
TDEE 随体重下降。 体重减轻后维持热量也会降，目标需要重新计算。
个体差异。 数据完全相同的两个人，每日消耗可能相差 200-300 千卡。

把这个数字当作起点，再根据两三周内体重的实际变化去调整。

Frequently Asked Questions

How many calories should I eat a day?

It depends on your size and activity. A sedentary adult woman needs roughly 1,800-2,000 calories a day, a sedentary man roughly 2,200-2,400, and active people considerably more. This calculator works it out from your own numbers.

What is the difference between BMR and TDEE?

BMR is what your body burns at complete rest just to stay alive. TDEE multiplies that by an activity factor to get the calories you actually burn in a normal day, which is the number that matters for weight change.

How fast can I lose weight safely?

Most guidelines suggest 0.5-1 kg (1-2 lb) a week. That corresponds to a daily deficit of about 500-1,000 calories. Faster loss is harder to sustain and tends to cost muscle as well as fat.

Last reviewed: October 5, 2026 · How we calculate · Sources: NIH, Academy of Nutrition and Dietetics