37 free reference tools · 7 categories
All Engineering Calculators
Choose the quantity or component you need to check. Each calculator below includes a stated model, input units, a worked example, and references. Open a category guide when you need help choosing between related tools.
Gears calculators
Calculate gear ratio, module and diametral pitch, spur gear dimensions, center distance, mesh forces, backlash, and simple planetary speeds.
- #001
Gear Center Distance Calculator
Calculate the nominal center distance, pitch diameters, and ratio of two standard external spur gears from module and tooth counts.
- #002
Gear Module / Diametral Pitch Converter
Convert gear module and diametral pitch in either direction, with equivalent metric and imperial circular pitch values, formulas, and engineering scope notes.
- #003
Gear Ratio Calculator
Calculate gear ratio, driven RPM, speed reduction or overdrive, and rotation direction for one external spur-gear pair.
- #005
Spur Gear Dimensions Calculator
Use this spur gear calculator to find pitch, outside, root, and base diameters from module or diametral pitch, tooth count, and pressure angle.
- #006
Gear Mesh Force Calculator
Calculate spur gear tangential, radial, normal, and axial mesh forces from torque, operating pitch diameter, and pressure angle.
- #007
Gear Backlash Calculator
Calculate spur gear circular, normal, and angular backlash from center-distance increase, or find the equivalent center-distance change.
- #008
Planetary Gear Ratio Calculator
Calculate simple planetary gear ratio, output RPM, direction, planet teeth, and equal-spacing phasing for sun, ring, or carrier configurations.
Shafts calculators
Calculate shaft torsion, diameter, bending stress, bearing reactions, deflection, critical speed, key stress, and rigid flange coupling loads.
- #020
Shaft Torsional Stress / Angle of Twist Calculator
Calculate torsional shear stress, angle of twist, polar moment, and stiffness for a solid or hollow circular shaft under elastic torsion.
- #021
Shaft Diameter Calculator — Torsional Stress / Twist
Size a solid or hollow shaft from torque, allowable nominal shear stress, and twist limits. Compare stress-controlled and stiffness-controlled diameters.
- #022
Shaft Combined Bending and Torsion Calculator
Calculate nominal shaft bending and torsional stress, principal stresses, and von Mises and Tresca equivalent stress from moments and shaft geometry.
- #023
Shaft Bearing Reactions / Bending Moment Calculator
Calculate two-support shaft bearing reactions, shear forces, and maximum bending moment from one or two transverse point loads.
- #024
Simply Supported Shaft Deflection / Slope Calculator
Calculate elastic deflection, maximum-deflection location, and support slopes for a simply supported circular shaft with up to two point loads.
- #025
Shaft Critical Speed / Whirling Calculator
Estimate single-rotor shaft critical speed from gravity static deflection and compare operating RPM with a user-selected review band.
- #026
Rayleigh Multi-Mass Shaft Critical Speed Calculator
Estimate shaft critical speed with Rayleigh’s method using up to four rotating weights and their station-specific total gravity deflections.
- #027
Dunkerley Multi-Mass Shaft Critical Speed Calculator
Estimate shaft critical speed with Dunkerley’s equation from up to four isolated single-mass gravity deflections. Review the model assumptions.
- #028
Shaft Key Shear / Bearing Stress Calculator
Calculate rectangular shaft-key shear and bearing stress, utilization, and required effective length using supplied allowable stresses.
- #029
Rigid Flange Coupling Bolt Shear Calculator
Calculate fitted-bolt shear stress, torque capacity, and required diameter for an ideal equal-radius rigid flange coupling.
- #030
Flange Coupling Bolt Bearing and Edge Shear-Out Calculator
Check nominal flange-hole bearing and edge shear-out, governing utilization, torque capacity, and required coupling flange thickness.
- #031
Flange Coupling Bolt Preload and Slip Resistance Calculator
Calculate ideal flange-coupling slip torque and required bolt preload from retained clamp force, friction coefficient, and annular contact geometry.
Bearings calculators
Calculate bearing L10 life, equivalent dynamic and static loads, required dynamic rating, static safety factor, and variable-duty equivalent load.
- #014
Bearing L10 Basic Rating Life Calculator
Calculate ISO 281 bearing L10 basic rating life in millions of revolutions, total revolutions, hours, days, or years from C, P, speed, and bearing type.
- #015
Bearing Equivalent Dynamic Load Calculator
Calculate radial-bearing equivalent dynamic load P from radial load Fr, axial load Fa, and manufacturer-supplied X and Y catalog factors.
- #016
Bearing Static Safety Factor Calculator
Calculate rolling-bearing static safety factor s₀, rating utilization, required C₀, and margin from verified basic static rating C₀ and equivalent static load P₀.
- #017
Bearing Equivalent Static Load Calculator
Calculate radial-bearing equivalent static load P₀ from paired maximum Fr and Fa loads, verified X₀ and Y₀ factors, and the applicable radial-floor rule.
- #018
Bearing Required Dynamic Load Rating Calculator
Calculate the minimum bearing basic dynamic load rating C required for a target ISO 281 L10 life from equivalent dynamic load P, speed, and bearing type.
- #019
Bearing Variable Duty Equivalent Dynamic Load Calculator
Calculate equivalent dynamic bearing load P_eq and mean RPM for a repeating variable-load, variable-speed duty cycle with up to four operating segments.
Belts calculators
Calculate V-belt datum length, timing-belt pitch length and tooth count, pulley speed ratio, belt speed, or pulley RPM with explicit diameter conventions.
- #010
V-Belt Length / Center Distance Calculator
Calculate approximate V-belt datum length from pulley diameters and center distance, or solve center distance from a known datum length.
- #011
Belt Speed / Pulley RPM Calculator
Calculate belt speed from pulley diameter and RPM, or solve pulley RPM from belt speed using metric or imperial units.
- #012
Pulley Speed Ratio / Driven RPM Calculator
Calculate driven pulley RPM, pulley speed ratio, speed multiplier, and ideal belt speed from two pulley diameters and driver RPM.
- #013
Timing Belt Length / Center Distance Calculator
Calculate exact timing belt pitch length, whole belt tooth count, center distance, pitch diameters, wrap angle, and teeth in mesh.
Chains calculators
Estimate roller-chain length and whole link count for an open two-sprocket drive, then check the center distance after choosing a link count.
- #009
Roller Chain Length Calculator
Calculate roller-chain length, whole and even link counts, nominal chain length, and achieved center distance for a two-sprocket chain drive.
Fasteners calculators
Estimate bolt torque and preload, bolt and clamped-member stiffness, external load sharing, joint separation, and thermal preload change.
- #032
Bolted Joint External Load Sharing and Separation Calculator
Calculate preloaded-joint bolt load increase, clamp relief, linear separation load, and a separate conservative preload-only reserve.
- #033
Bolt Axial Stiffness Calculator
Calculate bolt axial stiffness from shank and threaded effective lengths, tensile stress area, and elastic modulus using a series-compliance model.
- #034
Bolted Joint Clamped-Member Stiffness Calculator
Estimate symmetric clamped-member stiffness using compression frusta, a diameter limit, homogeneous material modulus, and joint geometry.
- #035
Multi-Layer Bolted Joint Clamped-Member Stiffness Calculator
Estimate three-layer clamped-member stiffness with separate material moduli, unequal bearing faces, segmented compression zones, and a diameter limit.
- #036
Bolted Joint Thermal Preload Change Calculator
Calculate signed thermal preload change from bolt and member expansion, compatible axial stiffnesses, effective lengths, and temperature changes.
- #037
Bolt Torque / Preload Calculator
Estimate bolt preload from tightening torque, or torque from target preload, with nut factor, running torque, installation tolerance, and variation.
Power transmission calculators
Convert between shaft power, torque, and rotational speed in SI or imperial units, then continue to gear, pulley, shaft, and bearing calculations.
- #004
RPM / Torque / Power Calculator
Calculate steady mechanical shaft power, torque, or RPM from the other two quantities, with metric and imperial unit conversion.