Built by fitness & tech people

Nutrition tools that actually show their work

MacrosMeasure was built on a simple idea: accurate health and nutrition tools should be available to everyone. We saw too many calculators hidden behind paywalls, registrations, and unnecessary barriers. So we created a platform where anyone can access reliable, research-backed calculators for free. Every tool is built using established formulas, reviewed against trusted sources, and designed to give clear, practical insights. No signup required, no subscriptions, and no hidden catches—just tools that help you make more informed decisions about your health and fitness.

18live calculators
0signups or paywall required

Our story

We kept running into the same wall

We're a small team of fitness enthusiasts, nutrition nerds, and developers who kept running into the same frustrating experience: finding a useful calculator, only to be met with a paywall, mandatory signup, endless ads, or unclear results with no explanation of where the numbers came from. So we built the platform we wished existed.

Every calculator on MacrosMeasure is designed to be accurate, transparent, and easy to use. We don't believe you should have to create an account or pay a subscription just to understand your calorie needs, body composition, hydration targets, or nutrition goals.

Our approach is simple: use established formulas, verify them against trusted research, and show our sources whenever possible. If a calculator uses a specific equation, you should be able to see where it comes from and understand why it works. Today, MacrosMeasure offers a growing collection of free tools covering body composition, calorie expenditure, macronutrient planning, ketogenic diets, intermittent fasting, hydration, strength training, recipe nutrition, and more. Every calculator is available to everyone, completely free, with no signups and no unnecessary barriers. Our goal is to make reliable nutrition and fitness information more accessible—one calculator at a time.

Accurate
Every calculator uses a named, peer-reviewed formula. No guesswork.
Transparent
We link to the original research. Read the source, not just our summary.
Accessible
No account. No payment. Open a tool, get a result. That's the whole experience.
Private
Your data never leaves your device. We don't collect it, store it, or see it.

The full toolkit

18 calculators, one place

Every tool is live and fully functional. No “coming soon” pages, no feature flags — if it's listed, it works.

Methodology

Every formula, explained

We use named, peer-reviewed formulas — not proprietary algorithms. Plain-English coverage of each one, with the original research linked.

01

Mifflin-St Jeor Equation

Most-used formulaCalorie CalculatorBMR CalculatorTDEE Calculator

The Mifflin-St Jeor equation, published in 1990, is the most widely validated formula for estimating Basal Metabolic Rate (BMR) — the number of calories your body burns at complete rest just to keep essential functions running. It takes four inputs: body weight, height, age, and sex.

The equations are:

Men: BMR = (10 × weight in kg) + (6.25 × height in cm) − (5 × age) + 5

Women: BMR = (10 × weight in kg) + (6.25 × height in cm) − (5 × age) − 161

To turn BMR into Total Daily Energy Expenditure (TDEE) — the calories you actually burn each day — we multiply it by an activity factor ranging from 1.2 (sedentary, desk job with little movement) up to 1.9 (very hard daily training or a physically demanding job). The result is your maintenance calorie level: eat at this number and your weight stays stable. Eat below it to lose; above it to gain.

We chose Mifflin-St Jeor over the older Harris-Benedict equation because controlled studies consistently show it is more accurate for modern adults — with average error rates around 10% versus Harris-Benedict's 15–20%. It is the formula recommended by the Academy of Nutrition and Dietetics for clinical practice.

02

U.S. Navy Circumference Method

Body Fat Calculator

Developed by the United States Navy, this method estimates body fat percentage from simple tape-measure readings — neck and waist for men; neck, waist, and hips for women. No equipment beyond a tape measure is needed, which is why it remains the standard for large-scale fitness assessments.

It is less precise than a DEXA scan or hydrostatic weighing, but for most people it provides a practical, repeatable estimate that is good enough to track progress over time.

03

Epley Formula (One-Rep Max)

1RM Calculator

Bryan Epley's 1985 formula estimates your one-rep maximum (1RM) from a lighter set — for example, the weight you can lift for 5 or 8 reps. This lets you gauge your theoretical maximum without the injury risk of attempting a true max lift.

It remains one of the most widely used formulas in strength and conditioning. Our calculator accepts any rep count from 1 to 12 and any exercise you choose to enter.

04

USDA FoodData Central

300,000+ foodsRecipe Nutrition Calculator

Our recipe nutrition analyser draws from USDA FoodData Central — the most comprehensive publicly available nutrient database in the world, covering over 300,000 foods and ingredients. It is maintained by the U.S. Department of Agriculture and updated on a regular basis.

When you enter ingredients into our recipe calculator, we query this database to return accurate macronutrient and micronutrient breakdowns per serving.

05

ACSM MET Values

Calories Burned Calculator

To estimate calories burned during exercise, we use Metabolic Equivalent of Task (MET) values aligned with American College of Sports Medicine guidelines. Each physical activity has a standardised MET value — running at 8 km/h is roughly 8 METs, for example, while light walking is around 3.

Multiplying the MET value by body weight in kg and duration in hours gives a reliable calorie-burn estimate rooted in exercise physiology research.

A note on individual variation: All formulas produce population-level estimates. Genetics, hormones, gut microbiome composition, sleep quality, and medication can cause individual results to deviate by ±10–15%. Our calculators give you an evidence-based starting point — not a clinically measured result.

Our commitments

What we will never do

These aren't marketing copy. They are constraints built into how this site operates — permanently.

We never sell your data

Your inputs stay in your browser. No biometric or health data you enter is collected, stored, or shared with anyone. Full stop.

We never require a signup

Every tool works without an account. Open a page, enter your numbers, get your result. That's it — no email, no profile, no friction.

We never give medical advice

Our results are mathematical estimates from published formulas. They are educational starting points, not clinical prescriptions.

We never use black-box algorithms

Every formula is named and cited. You can read the original research yourself. No proprietary scoring, no mystery output.

Important

Medical disclaimer

For informational purposes only

Results from MacrosMeasure calculators — including calorie targets, macro ratios, BMI classifications, body fat estimates, and weight recommendations — are mathematical estimates derived from population-based research formulas, provided for general informational and educational purposes only.

MacrosMeasure is not a medical service and does not provide medical, dietary, or clinical advice. Nothing on this website is intended to diagnose, treat, cure, or prevent any disease or health condition.

Always consult a qualified physician, registered dietitian (RD), or licensed healthcare provider before making significant changes to your diet, exercise, or supplement routine — particularly if you have a pre-existing condition, are pregnant or nursing, or are under active medical care.

For full details see our Disclaimer, Privacy Policy, and Terms of Service.

Found a formula issue? Want a new tool?

We read every message. If a calculation looks off, if you spotted a source we should cite, or if you need a calculator we haven't built yet — we'd genuinely like to hear about it.