Practical engineering tools and calculators.

Focused calculators with transparent methods and practical units for the garage, workshop and workbench.

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Percentage Difference / Ratio Calculator

Calculate percentage comparisons and simplify ratios.

Slope / Gradient Calculator

Convert rise, run, angle, percentage grade and slope ratio.

Tank Volume Calculator

Calculate full and partially filled tank volumes.

Automotive · 13 tools

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Wheel Fitment Calculator

Compare wheel widths, offsets and spacer effects.

Tyre Size Calculator

Compare tyre diameter, sidewall and speedometer change.

Gear Ratio / RPM Calculator

Relate road speed, engine RPM and drivetrain ratios.

Electrical · 11 tools

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Voltage Drop Calculator

Estimate voltage loss across cable runs.

Ohm’s Law Calculator

Calculate voltage, current, resistance and power.

Battery Runtime Calculator

Estimate useful runtime from capacity and load.

RF · 6 tools

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Frequency & Wavelength Calculator

Convert frequency, wavelength and common wave fractions.

dBm ↔ Watts Converter

Convert RF power between dBm, milliwatts, watts and kilowatts.

Quarter-Wave Antenna Calculator

Calculate theoretical antenna lengths from RF frequency.

Mechanical · 11 tools

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Hydraulic Cylinder Force Calculator

Calculate extension and retraction force from bore and pressure.

Pulley & Belt Ratio Calculator

Calculate belt-drive speed ratios and required pulley sizes.

Pipe Flow & Velocity Calculator

Relate pipe diameter, volumetric flow and fluid velocity.

Fabrication · 7 tools

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Material Weight Calculator

Estimate stock weight from material and dimensions.

Bolt Circle & PCD Calculator

Generate coordinates for evenly spaced holes on a PCD.

Bend Allowance Calculator

Calculate sheet-metal bend allowance, setback and bend deduction.

Machining · 6 tools

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Tap Drill Calculator

Find tapping drills for metric, UNC and UNF threads.

Speeds & Feeds Calculator

Calculate machining RPM, feed rate, surface speed and chip load.

Drill Size Converter

Match metric, fractional, number and letter drill sizes.

3D Printing · 6 tools

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3D Print Cost Calculator

Estimate filament, energy and machine costs.

Filament Length ↔ Weight Calculator

Convert 3D-printer filament length, weight and volume.

Resin Print Cost Calculator

Estimate resin material and optional electricity cost for a print.

General · 6 tools

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Engineering Unit Converter

Convert common workshop and engineering units.

Triangle Solver

Solve triangle sides, angles, area and perimeter.

Circle / Arc / Chord Calculator

Solve circle, arc, chord, sagitta and sector geometry.