Engineering Unit ConverterUNIT CONVERTER

1. 1Choose the quantity: length, thread pitch, gear module, torque or speed.
2. 2Pick the source unit — inch, TPI, DP, N·m, rpm and so on.
3. 3Type the value; the main conversion shows in large type and the other units are listed below.
4. 4Length conversions also give the nearest 1/64, 1/32 and 1/16 inch fractions with their error, handy for inch drawings and tooling.
5. 5Copy one or all results with 📋, or keep the conversion with the 🔗 share link.

Even metric designs keep running into inch parts: Unified screws, bearings, diametral-pitch gears and motor torque in oz·in or lbf·in. This tool puts the five conversions designers hit most on one page, and length results include the nearest fractional inch — 9.5 mm is closest to 3/8" (about −0.02 mm off) — which helps when choosing inch drills, extrusions or stock thickness.

A converted number is often not a catalogue size. A 1.27 mm pitch measured on an old machine is really 20 TPI; a module of about 1.06 mm is really a DP 24 inch gear. The converter lists the nearest ISO 261 pitch, Unified TPI, ISO 54 module and common diametral pitch so you can tell which standard the original part follows and avoid sizes that look close but are not compatible.

Motors, gearboxes and tightening torques are quoted in different units by different makers: N·m in Europe, kgf·cm in Japan and Taiwan, oz·in or lbf·in in the US. Every torque is converted to N·m first and then to the other units; speed uses rpm as the base for rad/s, rev/s and °/s. Combine it with the gear-ratio calculator to get output torque and speed after a reduction.

1 in = 25.4 mm (exact, since 1959)   ·   1 mil (thou) = 0.001 in = 25.4 µm
Thread: P [mm] = 25.4 / TPI   ·   TPI = 25.4 / P
Gear: m [mm] = 25.4 / DP   ·   circular pitch p = π · m   ·   CP [in] = π / DP
Torque: 1 kgf = 9.80665 N → 1 kgf·cm = 0.0980665 N·m
1 lbf·in = 0.112985 N·m   ·   1 lbf·ft = 1.35582 N·m   ·   1 ozf·in = 0.00706155 N·m
Speed: ω [rad/s] = 2π · n [rpm] / 60   ·   rev/s = rpm / 60   ·   °/s = 6 · rpm
Fraction: nearest k/64 in → k = round(64 · inch), reduced (e.g. 24/64 → 3/8")

Results are for design reference only; confirm against supplier catalogues and the applicable standards before manufacturing.