Enter the knowns, it solves the rest
Mark teeth, pitch, pressure angle, helix and backlash as known. Calculate fills in pitch diameter, module, circular pitch, base circle, lead and the rest, and keeps them up to date as you change an input.
For gear cutters, machinists and inspectors
Gear math for the shop floor.
Type what's on the print, press Calculate, get the reading you check with a mic. Over pins and over balls, span, and tooth or space thickness for spur, helical and internal gears.
- Windows desktop app
- Works offline
- Buy once, no subscription
91 T · 4.75 NDP · 20° NPA · 0.004 backlash
19.659112 in over 2 pins
What it does
The reading you actually measure
Measurement over 2 pins or balls, pin to center, a standard pin size and teeth in span. Odd tooth counts are measured over 2 pins or balls, with no 3-pin setup. Type a measured reading and it gives back the actual tooth thickness.
External and internal
Tooth thickness on external gears and space thickness on internals, with measurement between balls, inside diameter and base circle. Spur and helical, in inches or millimeters.
Jobs and reports
Save each gear as a job file with its name, part number and customer, and open it again with a double-click. Print the report or save it as a PDF for the traveler.
Two editions
Lite
The calculator
- External and internal workbenches
- Over pins, over balls, span and thickness
- Measured reading back to actual thickness
- Job files, print and PDF reports
- Inches or millimeters, light and dark themes
Pro Beta
Everything in Lite, plus
- Drawing: the gear and tooth to scale, with the reading marked
- Cycle time for hobbing
- Reverse engineering a gear from shop measurements
Join the pilot
Gear Shop Calculator is in a pilot with working gear shops before it goes on sale. Leave your email and we'll send you the installer when there's a place for you, then ask how it holds up against your own jobs.
We only use your email for the pilot and launch. We don't share it.