Free Machinist Calculators

Free shop calculators that run in your browser and work on a phone at the machine. No login, no install.

Three-Wire Thread Measurement Calculator
Free three-wire thread measurement calculator for 60° Unified (UNC/UNF) and ISO metric threads: best wire size, usable wire range and the measurement over wires M = E − 0.866025P + 3W.
ISO 286 Fit & Tolerance Calculator
Free ISO 286 fit calculator (hole basis, up to 500 mm): limits for H5–H11 holes and f, g, h, k, n, p shafts, clearance or interference, from the ISO 286-1 tables.
Bolt Circle Calculator
Free bolt circle calculator: X/Y coordinates for evenly spaced holes on a bolt circle diameter, with start angle, center offset and hole-to-hole spacing, inch or metric.
Speeds and Feeds Calculator
Free speeds and feeds calculator: spindle RPM from cutting speed (SFM or m/min) and tool or part diameter, table feed from flutes and chip load, and surface speed from RPM.
Sine Bar Calculator
Free sine bar calculator: enter the angle and sine bar length (5 in, 10 in, 100 mm, 200 mm) to get the gage block stack height, or enter a stack to get the angle, with rounding error in arc-seconds.
Gage Block Temperature Correction
Free thermal expansion calculator for gage blocks and parts: how much a steel, ceramic or carbide block and your part grow away from the 20 °C (68 °F) reference, and the correction to apply.
Gage Block Stack Calculator
Find the fewest-block stack for any size from your set. Free, no login.

Want background? See the machinist guides.