Free Gear Ratio Calculator
Calculate gear ratio, output speed and torque for one or two gear stages.
What is the Gear Ratio Calculator?
Calculate gear ratio, output speed and torque for one or two gear stages.
The ratio is driven teeth divided by driver teeth, multiplied across stages. Output speed is input RPM divided by the ratio, and torque is input torque times the ratio times the efficiency of each stage.
Quick, reliable engineering arithmetic saves time on site and in the workshop. These tools show their working so you can check the result.
How to use the Gear Ratio Calculator
Using the gear ratio calculator takes a minute or two. Your entries are saved in this browser, so you can come back later and carry on.
Step 1
Enter your values, choosing the units you are working in.
Step 2
Read the result and the supporting numbers shown beneath it.
Step 3
Check the result against a second method or a reference table before you rely on it.
Tips for better results
A ratio above 1 reduces speed and raises torque. Add a second stage for large reductions, but each stage adds some loss.
Keep units consistent from start to finish.
These tools are for estimates. Safety critical designs need a qualified engineer.
Privacy and where your data goes
Everything you type into the gear ratio calculator stays on your own device. Zapxa does not receive your numbers or documents. If you clear your browser data, your saved entries will be removed, so download a PDF of anything you want to keep.
Frequently asked questions
What does a 3:1 ratio mean?
The driver turns three times for one turn of the driven gear, so speed falls to a third and torque roughly triples, before losses.
How does efficiency affect torque?
Each stage multiplies torque by its efficiency, so two stages at 95 percent give about 90 percent.
Is the gear ratio calculator free?
Yes. It is free to use with no signup, no watermark and no usage limits.
Is my data private?
Yes. Your inputs are processed in your browser and saved only in its local storage. They are not uploaded to our servers.
Does it work on mobile?
Yes. Zapxa works on phones, tablets and desktops. Use the print button or download a PDF to keep a copy.
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