---
title: "Free Macro Calculator — Calories & Macros for Any Goal | Boost Fitness"
canonical_url: "https://boostfitness.io/tools/macro-calculator"
last_updated: "2026-07-11T17:44:36.983Z"
meta:
  description: "Free macro calculator: get your BMR (Mifflin-St Jeor), TDEE, and a daily protein, fat and carb split in grams for fat loss, maintenance or muscle gain."
  "og:description": "Free macro calculator: get your BMR (Mifflin-St Jeor), TDEE, and a daily protein, fat and carb split in grams for fat loss, maintenance or muscle gain."
  "og:title": "Free Macro Calculator — Calories & Macros for Any Goal | Boost Fitness"
---

Boost Fitness

# **Free macro calculator**

Work out your BMR with the Mifflin-St Jeor equation, your TDEE from your activity level, and a daily protein, fat, and carbohydrate target in grams for fat loss, maintenance, or muscle gain. This macro calorie calculator is free and needs no sign-up.

**Sex**

**Age (years)**

**Height**

**Weight**

**Activity level**

**Goal**

BMR (Mifflin-St Jeor)

**1770 kcal**

TDEE (maintenance)

**2740 kcal**

Daily calorie target

**2740 kcal**

Protein (30%)

**205 g**

Fat (30%)

**90 g**

Carbs (40%)

**275 g**

**General guidance, not medical advice**

This calculator gives population-level estimates for healthy adults. It is not a diagnosis or a prescription — speak to your GP or a registered professional before making significant changes, especially if you are pregnant, under 18, or managing a medical condition.

## How this macro calculator works

The calculation runs in three steps. First, your **basal metabolic rate (BMR)** — the energy your body uses at complete rest — is estimated with the **Mifflin-St Jeor equation** (10 × weight in kg + 6.25 × height in cm − 5 × age, plus 5 for men or minus 161 for women). It is the predictive equation most consistently found to be accurate for the general population, which is why dietitians favour it over the older Harris-Benedict formula.

Second, BMR is multiplied by an activity factor (1.2 for sedentary up to 1.9 for extra active) to estimate your **total daily energy expenditure (TDEE)** — what you actually burn across a normal day, training included. Third, your goal adjusts the target: a 20% deficit for fat loss, TDEE itself for maintenance, or a 10% surplus for muscle gain.

## From calories to macros

Calories are then divided between the three macronutrients using per-goal presets — for fat loss, 40% protein / 30% fat / 30% carbs; for maintenance, 30 / 30 / 40; for muscle gain, 30 / 25 / 45 — and converted to grams at 4 kcal per gram of protein and carbohydrate and 9 kcal per gram of fat. Protein stays high in every preset because it protects muscle and manages hunger; carbohydrate rises when the goal is gaining, because it fuels the training volume that drives growth. Grams are rounded to the nearest 5 — precision beyond that is noise once real-world food tracking is involved. If you want to sense-check the protein figure specifically, our [protein intake calculator](https://boostfitness.io/tools/protein-intake-calculator) shows the evidence-based range per kilogram of body weight.

## Limitations — and when a coach should adjust

Every number on this page is an estimate built from population averages. Mifflin-St Jeor is typically within about 10% of measured values, but that still means a 200+ kcal error for many people, and activity multipliers are honest guesses at best — most people overestimate their activity level by one category. Very muscular and very lean people tend to be underestimated; the equation also knows nothing about medical conditions, medications, or a history of aggressive dieting.

The fix is not a better formula — it is feedback. Track your intake and body weight for two to three weeks: if the scale trend does not match the goal (roughly 0.5–1% of body weight lost per week in a cut, 0.25–0.5% gained per month in a lean bulk), adjust calories by 10–15% and reassess. This is exactly the loop coaches run with [Boost Fitness nutrition coaching](https://boostfitness.io/features/nutrition): targets are prescribed to each client's calendar, the client logs food in the built-in diary, and the coach adjusts from real data instead of formulas.

## **Frequently asked questions **

## **More free tools **

**One Rep Max Calculator**

Estimate your 1RM from any set with the Epley and Brzycki formulas, plus a 50–95% loading table.

[One Rep Max Calculator](https://boostfitness.io/tools/one-rep-max-calculator)

**BMI Calculator**

Body mass index in metric or imperial units, with NHS categories and honest limitations.

[BMI Calculator](https://boostfitness.io/tools/bmi-calculator)

**Protein Intake Calculator**

An evidence-based daily protein range (1.2–2.2 g/kg) for your body weight and goal.

[Protein Intake Calculator](https://boostfitness.io/tools/protein-intake-calculator)

From Boost Fitness — see [~~nutrition coaching features~~](https://boostfitness.io/features/nutrition), [~~pricing~~](https://boostfitness.io/pricing), or [~~how we compare~~](https://boostfitness.io/compare).

## **Prescribe targets to clients automatically**

Boost Fitness turns numbers like these into daily calorie, macro, and training targets on each client's calendar — with a food diary, programme builder, and progress tracking built in. Start your 30-day free trial.

[Start your 30-day free trial](https://boostfitness.io/register) [Explore nutrition coaching](https://boostfitness.io/features/nutrition)

### **Targets that update themselves**

Set it once — your clients see it every day