Free Online Calculators for Money and Health
Loan and mortgage payments, compound interest, percentages, margins, VAT, tips, BMI, running pace. Each is a small formula you could do by hand and would rather not redo eleven times while changing one number. Results recalculate as you edit the fields, which makes them most useful for comparing scenarios side by side. They are arithmetic helpers, not financial or medical advice.
Tools in this category
- Percentage Calculator Calculate percentages, percentage change, and percentage of a number, all in one place.
- Percentage Increase Calculator Calculate the percentage increase or decrease between an old and a new value, with the signed percent change and the exact difference.
- Percentage Decrease Calculator Calculate the percentage decrease from an original value to a lower one. Get the percent decrease as a positive figure, the amount it dropped, and how much remains — perfect for discounts, markdowns, and price drops.
- Discount Calculator Calculate the sale price after a discount. Enter an original price and a percent off to instantly see the final price, how much you save, and the percentage of the price you still pay.
- Tip Calculator Calculate the tip and total for any bill, then split it between people. Enter the bill amount and a tip percentage to instantly see the tip, the grand total, and the amount each person owes.
- Loan Calculator Calculate your monthly loan payment from the loan amount, interest rate, and term. Instantly see the monthly payment, the total you'll repay, and the total interest for any personal, auto, student, or home loan.
- Compound Interest Calculator See how your money grows with compound interest. Enter a starting amount, annual interest rate, time, compounding frequency, and optional monthly contributions to instantly get the final balance, total contributed, and total interest earned.
- Simple Interest Calculator Calculate simple interest in seconds. Enter a principal, an annual interest rate, and a time in years or months to instantly see the total interest earned and the final balance, using the classic I = P × r × t formula.
- ROI Calculator Calculate return on investment (ROI) in seconds. Enter the amount you invested and the amount you got back to instantly see your ROI percentage and net profit, with an optional holding period for annualized ROI — all using the standard ROI = (gain − cost) / cost formula.
- Profit Margin Calculator Calculate profit margin in seconds. Enter your cost and your selling price (revenue) to instantly see your profit margin percentage, gross profit, and markup percentage — using the standard margin = (revenue − cost) / revenue × 100 formula.
- Markup Calculator Calculate markup percentage in seconds. Enter your cost and your selling price (revenue) to instantly see your markup percentage, gross profit, and profit margin — using the standard markup = (revenue − cost) / cost × 100 formula.
- VAT Calculator Add or remove VAT from any amount in seconds. Enter a price and a VAT rate to instantly see the net (pre-tax) amount, the VAT amount, and the gross (tax-inclusive) total — switch to reverse mode to extract the VAT already included in a price.
- Sales Tax Calculator Figure out sales tax on any purchase in seconds. Enter a pre-tax amount and your sales tax rate to instantly see the tax amount and the total with tax — or switch to reverse mode to back the sales tax out of a tax-inclusive total.
- Age Calculator Calculate your exact age in years, months, and days from your date of birth, plus age in weeks, days, hours, and a next-birthday countdown.
- Date Difference Calculator Calculate the exact difference between two dates in years, months, and days, plus the total in weeks, days, business days, hours, minutes, and seconds.
- BMI Calculator Calculate your Body Mass Index (BMI) from your height and weight in metric or imperial units, see your weight category, and the healthy weight range for your height.
- Pace Calculator Calculate running and walking pace, finish time, or distance. Enter any two of distance, time, and pace and get the third, in minutes per kilometre or per mile, with race-distance presets and your speed.
- Mortgage Calculator Estimate your monthly mortgage payment from the home price, down payment, interest rate, and loan term. Instantly see the monthly principal-and-interest payment, the loan amount, the total you'll repay, and the total interest over the life of the loan.
- Savings Calculator See how your savings grow over time. Enter an initial deposit, a monthly contribution, an annual interest rate, and the number of years, and instantly see your projected final balance, how much you'll deposit, the total of your monthly contributions, and the total interest earned with monthly compounding.
- Work Hours Calculator Add up the hours you worked from a clock-in and clock-out time. Enter your start time, end time, and any unpaid break, and instantly see your total hours worked as hours and minutes, as decimal hours, and as total minutes. Overnight shifts that cross midnight are handled automatically, and you can add an hourly rate to see your pay for the shift.
- Hourly Rate Calculator Convert a salary to an hourly rate, or an hourly rate to a salary, in seconds. Enter an annual salary (or an hourly wage), your hours worked per week, and the weeks you work per year, and instantly see your equivalent hourly, weekly, monthly, and annual pay. Switch direction with one click to work out what wage matches a target salary or what a salary works out to per hour.
- Electricity Cost Calculator Work out how much an appliance or device costs to run. Enter its power in watts or kilowatts, how many hours a day you use it, and your electricity price per kWh, and instantly see the energy it uses and what it costs you per day, week, month, and year. Perfect for sizing up heaters, air conditioners, computers, fridges, and any always-on gadget so you can spot the energy hogs and cut your bill.
- Storage Size Calculator Convert digital storage sizes between bytes, KB, MB, GB, TB, and PB in one click. Enter a value and unit, switch between decimal (1000-based) and binary (1024-based) bases, and instantly see the equivalent in every unit. Perfect for working out how big a file really is, why a 1 TB drive shows as 931 GB, or how much space a backup, dataset, or download will take.
- Aspect Ratio Calculator Calculate aspect ratios and resize width and height while keeping the same proportions. Enter an original width and height to see the simplified ratio (like 1920×1080 → 16:9), then type a new width or height and instantly get the matching dimension that preserves the ratio. Ideal for resizing images, videos, and screens, planning responsive layouts, and converting between common ratios like 16:9, 4:3, and 21:9.
- Screen Size Calculator Calculate the real width, height, area, and pixel density of any screen from its diagonal size and aspect ratio. Enter a diagonal in inches (like 27 inches) and a ratio (like 16:9) to get the exact physical width and height, the screen area in square inches, and — if you add the resolution — the pixels per inch (PPI). Perfect for comparing monitors, TVs, laptops, and phones, checking if a display fits a desk or wall, and judging how sharp a screen will look.
- Pixel Density Calculator Calculate the pixel density (PPI) of any screen from its resolution and diagonal size. Enter the horizontal and vertical pixels (like 2560 × 1440) and the diagonal in inches (like 27) to get the exact pixels per inch, the dot pitch in millimeters, the aspect ratio, and the total megapixels. PPI tells you how sharp a display will look — perfect for comparing monitors, laptops, phones, and TVs, checking if a screen is 'Retina-class', and judging detail at your viewing distance.
- Binary Calculator Add, subtract, multiply, divide, and run bitwise AND, OR, and XOR on binary numbers in your browser. Type two binary values, pick an operation, and instantly see the result in binary, decimal, hexadecimal, and octal. A fast, accurate binary math calculator for students, programmers, and anyone learning how binary arithmetic and bitwise logic work — no sign-up and nothing leaves your device.
- Scientific Calculator A free online scientific calculator with trigonometry, logarithms, powers, roots, factorials, and constants like π and e. Type a full expression or tap the buttons, switch between degrees and radians, and get an instant, accurate answer that respects the order of operations. It works entirely in your browser with no eval and no sign-up — a fast, private scientific calculator for math, physics, engineering, and homework.