Calculators
Age Calculator
Find exact age in years, months and days, plus total weeks and days between two dates.
Open tool →
Free Calculators
Accurate everyday calculators for age, percentages, BMI, calories and more — fast, private and free.
Available now
Calculators
Percentage Calculator
Calculate X percent of Y, reverse percentages, and percentage increase or decrease.
Open tool →
Calculators
BMI Calculator
Calculate body mass index in metric or imperial units, with category and healthy weight range.
Open tool →
Calculators
Calorie Calculator
Estimate BMR and daily calories for maintenance, weight loss and weight gain using Mifflin-St Jeor.
Open tool →
Calculators
Discount Calculator
Work out sale prices, savings and original prices from a discount percent.
Open tool →
Date & Time Tools
Pregnancy Due Date Calculator
Estimate a due date, conception date and gestational age from LMP, a known due date or conception using Naegele’s 280-day rule.
Open tool →
Coming soon
Calculators
Average Calculator
Calculate mean, and related averages from a list of numbers.
Coming soon
Calculators
Fraction Calculator
Add, subtract, multiply and divide fractions with simplified results.
Coming soon
Calculators
Ratio Calculator
Simplify ratios and scale quantities proportionally.
Coming soon
Related guides
- How to Calculate a Pregnancy Due DateNaegele’s rule is a 40-week calendar from LMP. Ultrasound and cycle length can move the date. This page will not replace a clinician.
- How to Calculate Discount and Sale Price“20% off” means you pay 80%. Reconstructing the original from a sale tag is a different formula.
- How to Calculate Daily CaloriesMaintenance calories are BMR times activity. A 500 kcal gap is a common planning figure — not a guarantee of 0.5 kg a week.
- How to Calculate PercentagePercent means “per hundred”. Most day-to-day questions collapse into three formulas — and one division-by-zero trap.
- How to Calculate AgeAge is a calendar difference, not “days ÷ 365”. Here is the method this site uses, including leap days.
- How to Calculate BMIBody mass index is a height-and-weight ratio, not a diagnosis. Here is the formula this calculator uses.