CalcShelf
Engineering shelf

Quick engineering calculators without the clutter.

Convert specs and run simple electrical/mechanical calculations for motors, vehicles, equipment, fluids, and everyday technical checks. These are educational tools — verify safety-critical work with qualified sources.

Convert power → Find an engineering calculator
Power, torque, voltage
Pressure, force, flow
Fast browser-only math
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Compare vehicle specs

Use horsepower, PS, torque, and torque-to-power tools for quick spec comparisons.

Check an electrical value

Use Ohm’s Law and power units to estimate volts, watts, current, and resistance relationships.

Convert equipment units

Switch pressure, flow, force, density, and energy units without digging through dense tables.

Prepare a spec check

Keep the source rating, converted value, and manufacturer limit together before using a number in a quote, repair, or design note.

Worksheet habit

Use conversions as a spec check, not a final approval.

Start with the source unit

Record the value exactly as it appears on the label, manual, drawing, or datasheet before converting it.

Compare with margin

Use derating, headroom, or tolerance rows where the individual calculator provides them, then flag assumptions that drive the result.

Verify safety-critical work

Treat electrical, pressure, lifting, fluid, and vehicle results as planning aids. Confirm code, manufacturer, and qualified-engineer requirements before acting.

Calculator finder

Find an engineering calculator

Curated starting points

Search by goal, topic, or unit. Results update locally in your browser.

EngineeringPower ConverterConvert watts, kilowatts, horsepower, metric horsepower, BTU/hour, and foot-pounds per second.EngineeringHP to PS ConverterConvert mechanical horsepower, metric horsepower (PS), and kilowatts.EngineeringTorque ConverterConvert newton-meters, pound-feet, pound-inches, kgf·m, and kgf·cm.EngineeringOhm’s Law Voltage CalculatorCalculate voltage and power from current and resistance using Ohm’s Law.EngineeringTorque and RPM to Horsepower CalculatorEstimate horsepower, kilowatts, and PS from torque and RPM for motor and engine comparisons.EngineeringPressure ConverterConvert PSI, bar, kPa, MPa, pascals, atmospheres, and torr for pressure specs and checks.
Popular tools

Start with a useful one

These are the calculators people are most likely to need first.

Engineering Power Converter

Convert watts, kilowatts, horsepower, metric horsepower, BTU/hour, and foot-pounds per second.

Open calculator → Engineering HP to PS Converter

Convert mechanical horsepower, metric horsepower (PS), and kilowatts.

Open calculator → Engineering Torque Converter

Convert newton-meters, pound-feet, pound-inches, kgf·m, and kgf·cm.

Open calculator → Engineering Ohm’s Law Voltage Calculator

Calculate voltage and power from current and resistance using Ohm’s Law.

Open calculator → Engineering Torque and RPM to Horsepower Calculator

Estimate horsepower, kilowatts, and PS from torque and RPM for motor and engine comparisons.

Open calculator → Engineering Pressure Converter

Convert PSI, bar, kPa, MPa, pascals, atmospheres, and torr for pressure specs and checks.

Open calculator → Engineering Energy Converter

Convert joules, kWh, BTU, calories, kilocalories, watt-hours, and foot-pounds.

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How to use this shelf

Best for

Use this shelf for quick formula and unit checks before specs, quotes, drawings, or part selections get more expensive to fix.

Choose the right tool

Use converters for unit cleanup, Ohm law for electrical relationships, and torque RPM horsepower when powertrain or motor math needs a sanity check.

Verify before acting

Check units, tolerance, safety factor, operating environment, duty cycle, heat, code requirements, and manufacturer limits before acting.

Suggested workflow: A good technical workflow is: normalize units, run the formula, check order of magnitude, then verify against the datasheet or governing standard.