About ToolsEngg

ToolsEngg is a free reference site for machinists, manufacturing engineers, students and makers.

What we build

Two things, done properly: a machine-shop calculator suite (speeds and feeds, metal removal rate, unit-power horsepower, tap drill sizing, ISO 21940 balancing, GD&T true position, bolt circles, hardness conversion and cost justification) and a complete unit conversion library spanning everyday, engineering, heat, fluids, electrical, magnetic and radiology units.

How it works

Every calculation runs locally in your browser using documented formulas and exact conversion constants. There is no account system, no per-query credits and no server round-trip — results are instant and private.

Quality & trust

Formulas follow standard machining handbook and ISO definitions; conversion factors use legal definitions and CODATA constants. Each calculator page shows the formula it uses so you can verify the math yourself.

General inquiries

Spot an error or want a calculator added? Reach us through the contact links in the footer.