Know your numbers, feel your best
Health calculators for weight, nutrition, sleep, cycle and pregnancy — private, simple and instant.
⭐ Featured tools
🆕 New tools
📚 Guides
⚖️ Body & Weight
BMI Calculator
Calculate your Body Mass Index (BMI) using the standard WHO categories — underweight, normal weight, overweight, and obese. Free, instant, informational only.
Ideal Weight Range Calculator
Calculate your healthy weight range based on your height, using the standard WHO normal BMI range of 18.5 to 24.9. Free calculator with instant results.
Body Fat Percentage Calculator
Estimate your body fat percentage with the US Navy method using height, neck, waist and hip measurements. Free calculator with fitness categories.
Waist-to-Hip Ratio Calculator
Calculate your waist-to-hip ratio (WHR) and compare it with World Health Organization cut-offs for men and women.
Waist-to-Height Ratio Calculator
Calculate your waist-to-height ratio (WHtR). A ratio under 0.5 means your waist is less than half your height — a simple health guideline.
Lean Body Mass Calculator
Estimate your lean body mass (everything except fat) from height, weight and sex using the Boer formula.
Body Surface Area Calculator
Calculate body surface area (BSA) in square meters from height and weight using the Mosteller formula.
Weight Loss Calculator
Estimate how long it takes to reach a goal weight at a steady weekly rate, your target date, and the rough daily calorie deficit needed.
🍽️ Nutrition
Daily Calorie Needs Calculator
Calculate your estimated daily calorie needs based on your BMR and activity level, from sedentary all the way up to very active or highly athletic training.
BMR Calculator
Calculate your Basal Metabolic Rate (BMR) — the calories your body burns at complete rest — using the widely trusted Mifflin-St Jeor equation formula.
Macro Calculator
Free macro calculator. Turn your daily calories into grams of protein, carbohydrate and fat for a balanced, low-carb, high-protein or keto split.
Protein Intake Calculator
Calculate how many grams of protein you need per day based on your weight and activity level, from basic health to muscle building.
😴 Sleep & Hydration
Sleep Duration Calculator
Find the generally recommended amount of sleep for any age, based on published Sleep Foundation guideline ranges, from newborn babies to older adults.
Water Intake Calculator
Estimate your suggested daily water intake based on body weight, using the commonly cited 33ml-per-kilogram general hydration guideline. Free and fast.
📍 Pregnancy & Cycle
Pregnancy Due Date Calculator
Calculate your estimated pregnancy due date from the first day of your last menstrual period, using the standard 280-day (40-week) obstetric dating method.
Pregnancy / Gestational Age Calculator
Calculate gestational age in weeks and days from your last menstrual period, plus your current trimester and estimated pregnancy due date. Free and instant.
Conception Date Calculator
Estimate your conception date from either your last menstrual period or your due date. Free, simple pregnancy dating calculator, no signup needed at all.
Ovulation Calculator
Estimate your ovulation date and most fertile days from the first day of your last period and your average cycle length.
Period Calculator
Predict the start and end dates of your next three periods from your last period, average cycle length and period length.
Pregnancy Weight Gain Calculator
See the recommended total pregnancy weight gain for your pre-pregnancy BMI and a typical range for your current week (single baby).
Frequently Asked Questions
Do I need to sign up or log in?
No. Every calculator works instantly without an account. A free account is only needed if you want to save results (up to 30) and see them later.
Is my data stored anywhere?
The numbers and dates you type are calculated in your browser and are not sent to us. We keep basic visit statistics (page visited, IP address, browser, time) and, if you save a result, that saved result in your account. The AI Assistant sends your question to an AI provider to answer it.
Are the results exact?
Date and age maths is exact. Money, tax and health tools are estimates based on published formulas and official tables, and are not professional advice.