Free Online Calculators & Device Tests
24 free tools, without a sign-up. Check keyboards, mice, controllers and speaker channels before buying used equipment or after a change, or calculate pay, tax and everyday costs. Each tool explains its inputs and limitations.
Device tests
Speaker Test
Check left and right speaker or headphone channels with short stereo tones. Record what you hear, compare two tests and print a local report. No download.
Start test →Gamepad Tester
Test controller buttons and analog sticks in your browser. Sample resting offset, compare two sessions and print a local report. No download or upload.
Start test →Keyboard Tester
Test physical keyboard keys, left and right modifiers and held combinations. Compare before and after tests and print a report. No download or upload.
Start test →Mouse Test
Check mouse buttons, scroll directions and rapid double-click pairs with an adjustable threshold. Compare two tests and print a local report.
Start test →Finance
eBay Fee & Profit Calculator
Estimate eBay.com fees and profit for US domestic non-Store sales in selected categories. Compare scenarios or calculate a price for your target profit.
Open calculator →Turkey Income Tax & Net Salary Calculator
Calculate Turkish monthly net salary from gross pay for 2026. See a 12-month breakdown of income tax, SGK, unemployment and stamp tax.
Open calculator →Compound Interest Calculator
See what a deposit grows to with compound interest. Set the rate, the term and how often interest is added, and compare it with simple interest.
Open calculator →VAT Calculator
Enter an amount and VAT rate to see the gross price, net price and VAT included in a gross total. Works with a rate you supply.
Open calculator →Salary to Hourly Calculator
Convert annual salary to hourly pay or an hourly rate to annual and monthly gross pay. Set your hours per week and paid weeks per year.
Open calculator →Savings Goal Calculator
Calculate the monthly contribution needed to reach a savings target, with an interest-rate assumption and a comparison without interest.
Open calculator →Health
BMI Calculator
Calculate body mass index from height and weight in metric or imperial units, see the WHO category boundaries and what BMI does not measure.
Open calculator →TDEE & Calorie Calculator
Estimate maintenance calories, resting energy needs and a fixed 500-calorie deficit using Mifflin-St Jeor and your activity level.
Open calculator →Home & auto
Paint Calculator
Calculate paint in litres and US gallons from wall area, coats and product coverage, including an adjustable-input estimate with a fixed 10% waste allowance.
Open calculator →Fuel Cost Calculator
Work out what a journey costs in fuel from distance, consumption and pump price, with cost per kilometre and the litres you will burn.
Open calculator →Tire Size Calculator
Compare original and new tire sizes. Calculate diameter, circumference, percentage difference and theoretical speed at your indicated speed.
Open calculator →Area Calculator
Calculate rectangular area in square metres and square feet, plus a flooring order estimate with your chosen waste percentage.
Open calculator →Electricity Cost Calculator
Calculate an appliance’s daily, monthly and yearly electricity cost using watts, hours per day and your price per kWh.
Open calculator →Everyday
Percentage Calculator
Calculate a percentage of a number, find what percent A is of B, or work out percentage change between old and new values.
Open calculator →Discount Calculator
Enter the original price and the discount to see the sale price and the saving, including how stacked discounts really combine.
Open calculator →Tip Calculator
Work out the tip and the total, split it between any number of people, and check customary tipping rates before you travel.
Open calculator →Risk Assessment Matrix Calculator
Calculate a 5×5 likelihood and severity risk score. Read the example action bands and adapt them to your organisation policy.
Open calculator →Unit Price Calculator
Compare two products by price per unit when the pack sizes differ, and see how much the larger pack really saves.
Open calculator →Word Counter
Paste or type text to count words, characters, sentences and paragraphs instantly. Estimate reading time in your browser without uploading text.
Open calculator →Days Between Dates Calculator
Count the days between two dates, with whole calendar months, weeks and the number of weekdays excluding Saturdays and Sundays.
Open calculator →