Are these health and fitness calculators free?

YellowNex brings the most useful health and fitness calculators together in one fast, installable web app. Estimate your body mass index, daily calories, macros, body fat, heart rate zones and more. Everything runs on your phone, needs no sign-up and is free.

Which Calculator Should I Use?

Lose weight: start with the calorie calculator, then check your timeline with the weight loss calculator.
Build muscle: use the TDEE calculator, the protein intake calculator and the one rep max calculator.
Plan your meals: the macro calculator splits calories into protein, carbs and fat.
Check your body: try the BMI calculator, the body fat calculator and the ideal weight calculator.
Train smarter: the heart rate zone calculator and the calories burned calculator.
Stay hydrated: use the water intake calculator and the water intake tracker.
Expecting: the pregnancy due date calculator estimates your due date.

How These Calculators Work

BMI

BMI equals weight in kilograms divided by height in meters squared. A result of 18.5 to 24.9 is usually called a healthy range for adults, but BMI does not measure body fat or muscle.

BMR and TDEE

Many calculators use the Mifflin-St Jeor equation for basal metabolic rate (BMR): 10 × weight (kg) + 6.25 × height (cm) − 5 × age + 5 for men, or − 161 for women. Multiply BMR by an activity factor from 1.2 (sedentary) to 1.9 (very active) to get your total daily energy expenditure (TDEE).

Weight loss

About 7,700 kcal equals 1 kg of body fat (3,500 kcal per pound). A daily deficit of 500 kcal leads to roughly 0.5 kg (1 lb) of loss per week. This is an estimate, since real results vary.

Macros and protein

Protein has 4 kcal per gram, carbs 4 and fat 9. The general recommended minimum for adults is 0.8 g of protein per kg of body weight, while active people often aim for about 1.4 to 2.0 g per kg.

Heart rate zones

A common estimate for maximum heart rate is 220 minus your age. Training zones are percentages of that number, from about 50% for easy effort to 90% or more for hard intervals.

One rep max

The Epley formula estimates your 1RM as weight × (1 + reps ÷ 30). It is most accurate for sets of 10 reps or fewer.

Due date

Naegele's rule adds 280 days (40 weeks) to the first day of your last menstrual period.

Install the App on Your Phone

Open the Install tab for step-by-step instructions on Android and iPhone. Once added to your home screen, the calculators open full screen like a native app.

Frequently Asked Questions

Are the calculators accurate?

They use standard, widely accepted formulas, but they are estimates. Individual needs vary.

Do you store my data?

No. Your inputs stay on your device. Your saved favorites are stored only in your browser.

Do I need an account?

No account or sign-up is needed.

These tools provide general information, not medical advice. Consult a doctor or registered dietitian before changing your diet, training or health routine.

Saved Calculators

Tap ☆ on any calculator to keep it here for quick access.

Nothing saved yet. Go to Tools and tap the star.

Install the App

Add the calculators to your home screen. They open full screen like a native app.

Android (Chrome)

Tap the ⋮ menu in the top right.
Tap “Install app” or “Add to Home screen”.
Open it from your home screen. The logo launches the app directly.

iPhone / iPad (Safari)

Open this page in Safari (it won't work from Chrome).
Tap the Share icon (square with an arrow) at the bottom.
Scroll down and tap Add to Home Screen.
Tap Add in the top right. The icon appears on your home screen.

About

YellowNex Health & Fitness Calculators is a free, installable web app (PWA) with 15 calculators for weight, nutrition, training, hydration and pregnancy.

Your inputs stay on your device. The results are general estimates and not medical advice.

yellownex.com