ENGINEERING CALCULATORS
Mechanical design calculators
Gear ratio, centre distances for gears, GT2 belts, V-belts and roller chains, ISO fits and tolerances, stepper steps/mm and LED resistors — instant results, shareable links, and one click to the matching 3D part generator.
- 12CALCULATORS · FREE
Power transmission
6- GEAR RATIOGear Ratio CalculatorEnter driver and driven tooth counts for 1–3 gear stages plus input speed and torque to get each stage ratio, the total ratio, output speed, output torque and rotation direction (98% efficiency per stage by default).η 0.98 / stageISO 54 moduleOpen
- GEAR CENTER DISTANCESpur Gear Center Distance CalculatorEnter the module and both tooth counts — plus optional profile shift and pressure angle — to get the spur-gear centre distance, working pressure angle and each gear's pitch, tip, root and base diameters.ISO 53ISO 21771JIS B 1701Open
- PROFILE SHIFTGear Profile Shift CalculatorEnter module, tooth counts, pressure angle and the target centre distance a' to solve the working pressure angle α' and the total profile shift Σx, split it between both gears and check undercut, pointed tips and tip shortening. Free, with one-click hand-off to the spur gear pair generator.ISO 21771DIN 3992JIS B 1701Open
- GT2 CENTER DISTANCEGT2 Belt Center Distance CalculatorEnter a closed GT2 belt length and two pulley tooth counts to solve the centre distance numerically from the exact open-belt length formula, with speed ratio, wrap angles and teeth in mesh.GT2 2 mm pitch2GTOpen
- V-BELT CENTER DISTANCEV-Belt Length & Center Distance CalculatorFor ISO 4184 / CNS 4218 classical V-belts A–E: enter both sheave pitch diameters and the desired centre distance to get the nearest standard belt, its pitch length, the actual centre distance, error, ratio, wrap angle and belt speed.ISO 4184CNS 4218JIS K 6323Open
- ROLLER CHAIN CENTER DISTANCERoller Chain Length & Center Distance CalculatorEnter the chain number, sprocket tooth counts and the desired center distance to get the even link count, actual center distance, error, pitch diameters and ratio. JIS B 1801 / ANSI B29.1 formulas, free online.JIS B 1801JIS B 1802ANSI B29.1Open
Fits, tolerances & threads
3- ISO FIT TOLERANCEISO Fit Tolerance CalculatorEnter a nominal size and hole/shaft tolerance classes (e.g. H7/g6) to get ES/EI/es/ei, maximum and minimum clearance or interference and the fit type instantly. Full ISO 286-1:2010 / JIS B 0401 tables, 1–3150 mm, free online.ISO 286-1:2010ISO 286-2:2010JIS B 0401Open
- TAP DRILL & CLEARANCE HOLETap Drill & Clearance Hole CalculatorPick a metric (M1–M30 coarse / fine) or UNC / UNF thread and get the tap drill, thread engagement, minor diameter, ISO 273 clearance holes (fine / medium / coarse), socket-head counterbore, plus 3D-printing self-tap and heat-set insert hole sizes.ISO 261 / 262ISO 2306ISO 273Open
- HOLE COMPENSATION3D Printing Hole Compensation CalculatorEnter the nominal diameter, print process (FDM / SLA / SLS / MJF), hole orientation and fit to get the diameter to draw in CAD, the expected printed diameter, STL polygon error and whether a horizontal hole should be a teardrop. Free online; numbers match our hole-tolerance guide.FDM · SLA · SLS / MJFISO 286 fitsOpen
Electronics & motion
2- STEPS PER MMStepper Motor Steps per mm CalculatorEnter step angle, microstepping and either leadscrew lead or belt pitch × pulley teeth to get the steps/mm your 3D printer or CNC firmware needs, plus resolution per step and travel per pulse count. Works for Marlin, Klipper and GRBL — free online.NEMA 17 / 23Marlin · Klipper · GRBLOpen
- LED RESISTORLED Resistor CalculatorEnter supply voltage, LED forward voltage, current and the number of LEDs in series to get the current-limiting resistor, the nearest E12 / E24 standard value, actual current, resistor power and recommended wattage. Free online.IEC 60063 E12 / E24Ohm's lawOpen