Free, simple tools that run in your browser. No sign-up, nothing is stored or sent anywhere.
25 free calculatorsNo signupWorks on phone
โก For engineers
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Transformer kVA and load calculatorFind the right transformer size and full-load current.Open the tool โโฑ๏ธ
Energy meter fast or slow errorCheck if a meter runs fast or slow and by how much.Open the tool โ๐
Cable size calculatorCable size and breaker from load, length and voltage drop.Open the tool โ๐
Voltage drop calculatorVolts and percent lost in a cable run.Open the tool โ๐๏ธ
Power factor correctionCapacitor kVAR needed to reach your target power factor.Open the tool โโ๏ธ
Motor current and breakerFull-load current, breaker, overload and cable for a motor.Open the tool โ๐ข๏ธ
Generator size calculatorGenerator kVA for your load and motor starting.Open the tool โ๐งต
AWG to mm2 converterWire size in AWG and mm2, both ways.Open the tool โฮฉ
Ohm’s law calculatorEnter any two of V, I, R, P and get the rest.Open the tool โโ๏ธ For homes, solar and backup power
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Home wiring load calculatorTotal load, main breaker and circuits for your house.Open the tool โ๐ก
Electricity cost calculatorWhat any appliance costs per day, month and year.Open the tool โ๐ฟ
Geyser and water pump costRunning cost of a geyser or pump with thermostat duty cycle.Open the tool โโ๏ธ
AC tonnage calculatorHow many tons of AC your room needs.Open the tool โโ๏ธ
Solar system size calculatorPanels, inverter and battery bank for your home.Open the tool โ๐
Solar payback calculatorHow many years until solar pays for itself.Open the tool โ๐
Inverter and UPS sizeVA rating, system voltage and battery for your load.Open the tool โ๐
Battery backup time calculatorHow long a battery runs your load, or what size you need.Open the tool โ๐ผ For small business and money
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Profit margin and markup calculatorMargin, markup and the selling price you need.Open the tool โ๐ฆ
Loan EMI calculatorMonthly instalment, total interest and total payment.Open the tool โ๐งพ
GST and VAT calculatorAdd tax to a price or remove it from a total.Open the tool โ๏ผ
Percentage calculatorPercent of, percent change, increase and decrease.Open the tool โ๐ For teachers and students
โ๏ธ For writers and AI users
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Word counter and reading timeWords, characters and reading time in seconds.Open the tool โ๐ค
AI token counter and prompt length estimatorEstimate tokens before you paste into an AI tool.Open the tool โโณ
AI time saved calculatorHours per week and year that AI can give back.Open the tool โWant ready-to-use AI prompts too? Download our free prompt guides.