Engineering Reference

MechRef

Mechanical Engineering · At Your Fingertips

Professional mechanical engineering reference and calculator app. Threads, fits, gears, springs, shafts and more — based on international standards. Inspired by the classic reference book Máquinas by A.L. Casillas.

ISO Standards One-time purchase No subscription No ads EN · ES
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// Microsoft Store coming soon

Threads module
MechRef home
Fits and tolerances
11
Modules
180+
Unit Conversions
65
Eng. Constants
2
Languages
Modules

What's Inside

Every module is built around real engineering needs, with data and formulas based on international standards.

Free
Threads
ISO Coarse, ISO Fine, UNC, UNF — with tap drill recommendations for every size.
Free
Fits & Tolerances
ISO 286-1 hole basis system with visual tolerance diagrams and fit classifications.
Free
Converter & Constants
180+ unit conversions across 14 disciplines, plus 65 engineering and physics constants.
Free
Areas & Volumes
2D and 3D geometry calculations for the most common engineering shapes.
Pro
Geometry & Trig
Triangle solver, arc & sector, trig functions, and polygon calculations.
Pro
Gears
Spur, helical, rack & pinion, bevel gears — ISO modules, pitch, ratios.
Pro
Springs
Compression, extension, torsion, and leaf spring design calculations.
Pro
Shafts & Keys
Design by torque, bending moment, and keyway selection.
Pro
Belts & Chains
V-belt, flat belt, roller chain, timing belt — power and tensions.
Pro
Machining
Cutting speed, feed rate, material removal rate, and power calculations.
Pro
More Coming
More Pro modules are in development and will be available in future updates.
⚡ MechRef Pro

Unlock the Full Toolkit

A single one-time purchase gives you access to all Pro modules — current and future — with no recurring fees, no ads, and no account required.

  • Gears calculator
  • Spring design
  • Shaft & key selection
  • Belt & chain drive
  • Machining parameters
  • Geometry & trig solver
  • All future Pro modules
  • Priority support
One-time purchase
Pro
// No subscription · No ads · No account
  • Available on Google Play
  • Available on Microsoft Store
  • English & Spanish
  • Works offline
  • All future Pro modules included
Screenshots

See It in Action

Home screen
Threads module
Fits and Tolerances
Areas and Volumes
Converter and Constants