Engineering Calculators
Engineering Calculators
Practical tools for the shop floor and the drawing board. No login, no ads — just the math.
Bolt Torque & Preload
Calculate bolt preload from applied torque, or required torque for a target clamp load. Covers SAE, metric, and stainless fasteners with friction coefficients.
Fraction Converter
Convert any decimal or mm dimension to the nearest imperial fraction — floor, ceiling, or closest — to any denominator from halves to thousandths. Exact-match detection included.
GD&T Bonus Tolerance
Calculate bonus tolerance for MMC and LMC material condition modifiers. Shows virtual condition, resultant condition, and total tolerance across the size range.
Tap Drill Finder
Find the right tap drill for any UNC, UNF, UNEF, or metric thread. Adjustable thread engagement percentage with nearest standard drill sizes — number, letter, fractional, and metric.
Press Fit Stress
Lamé equations for hoop and radial stress — hub/shaft interference fits. Multi-material.
Feeds & Speeds
RPM, feed rate, and chip load for milling, turning, drilling, and tapping.
Bend Allowance
K-factor based flat pattern length, bend allowance, and bend deduction.
Hardness Converter
HRC ↔ HRB ↔ HV ↔ HB cross-reference with approximate UTS — ASTM E140.
Beam Deflection
Max deflection and bending stress for common load cases and cross-sections.