Measure it before you build it
Workshop Calculators
Practical calculators for building, measuring, wiring and fixing. They accept the measurements people actually use, including fractions, decimals, feet, inches and millimeters.
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Frequently useful calculators
Fraction to Decimal
Convert fractions and mixed numbers into decimals, millimeters and percentages.
Metric and Imperial
Enter a measurement the way you normally write it and see every useful equivalent.
Feet and Inches
Add, subtract, multiply or divide feet, inches and fractions without treating inches like base ten.
Browse by category
Measurement
Fractions, decimals, metric, imperial, scale and tolerances.
Geometry and Layout
Spacing, hole placement, circles, angles and practical layout.
Woodworking
Lumber, kerf, cutting, joinery and instrument building.
Mechanical
Bearings, pulleys, gears, shafts and moving parts.
Electrical
Resistance, power, speakers, batteries and workshop electronics.
Materials
Volume, weight, density and quantity.
Construction
Paint, concrete, framing, surfaces and repair estimates.
Finishing
Coatings, epoxy, catalyst, reducer and finishing quantities.
Why this exists
The answer is not useful unless you know what it means.
I built this site because workshop math often starts with a simple question and turns into three conversions, a sketch on scrap paper, and another calculator to check the first one. These tools are meant to keep that from happening.
The calculators show the math, explain what the result means, and name the things the calculation cannot see. A number is not a safety inspection, and it does not know whether the board is cracked, the bearing is side loaded, or the measurement came from the wrong edge.
About Workshop Calculators