The right number, in seconds
Free calculators for finance, real estate, construction and everyday life. Real-time results, explained methods, no sign-up.
Popular calculators
- Finance APY calculator Convert an interest rate (APR) into APY for any compounding frequency, then see what your savings account or CD earns with monthly deposits.
- Health BMI calculator Calculate your body mass index from your weight and height in pounds and inches or kilograms and centimeters, see your category and the weight range that matches a healthy BMI.
- Health BMR and calorie calculator Estimate your basal metabolic rate and total daily energy expenditure from your age, sex, height, weight and activity, then the calories to maintain, lose or gain weight steadily.
- Finance 50/30/20 budget calculator Divide your monthly take-home pay into needs, wants and savings, and compare with what you spend today.
- Finance Auto loan calculator Price your next car loan with the down payment, trade-in and sales tax included, and compare loan terms.
- Health Body fat calculator Estimate your body fat percentage from your height and neck, waist and hip measurements using the US Navy method, then your fat mass, lean mass and fitness category.
- Finance Break-even calculator Find how many units you must sell each month to cover fixed costs, and how much safety margin your sales forecast leaves.
- Construction Brick calculator Estimate how many bricks and bags of mortar a wall needs, for modular, standard, queen or king size brick.
- Finance Car depreciation calculator Estimate a car's value after each year of ownership and what depreciation costs you per month.
- Finance CAGR calculator Measure the smoothed yearly growth rate between a starting and ending value, for a portfolio, revenue, a home price or any metric.
- Real estate Closing costs calculator Estimate the buyer's closing costs on a home purchase: lender fees, title and settlement, transfer taxes and prepaid escrow, plus the total cash you need at closing.
- Finance Compound interest calculator See how an initial deposit, regular monthly contributions and an annual return grow over time, and what the result is worth after inflation.
Browse by category
Finance
Savings, interest, inflation, salary: clear financial calculators to run your budget.
138 calculators
Real estate
Mortgages, borrowing capacity, closing costs, rental yield: plan your property project with confidence.
17 calculators
Construction
Concrete, masonry, areas, materials: get the exact quantities for your job site and avoid waste.
166 calculators
Health
BMI, metabolism, body fat, heart-rate zones: numbers that help you track your fitness, without replacing advice from a health professional.
322 calculators
Sports
Steps, cycling, swimming, running, golf, powerlifting: calculators to measure effort, set your pace and track progress.
57 calculators
Everyday life
Percentages, discounts, fuel, electricity: everyday maths done in a second, without mistakes.
187 calculators
Math
Fractions, proportions, geometry, averages and probability: school and everyday math solved step by step, with the method explained.
115 calculators
Conversions
Length, weight, volume, temperature, cups to grams, energy, data size, large numbers and more: two-way unit converters with exact formulas and printable conversion charts.
415 calculators
Cooking
Yeast, bread dough, pasta and rice portions, turkey, coffee: the right amounts in the kitchen, without waste.
60 calculators
Pets
Dog and cat years, how much to feed, chocolate risk, fish tanks: practical numbers for looking after your pets.
31 calculators
Science
Dew point, lightning, free fall, Ohm's law, wire size, batteries, gears: everyday physics, with the formulas explained.
232 calculators
Why Omnikalc?
Instant
Results update as you type, with no page reload.
Transparent
Every formula is explained in a full guide with worked examples.
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Share a pre-filled calculation or embed the calculator on your site.