Gear Train Simulator
Drag gears together to mesh them, then see speed and torque change through the train.
Drag a gear next to another until it snaps into mesh. Grab the orange knob to spin the driver by hand.
| Gear | Teeth | Speed | Direction | Torque |
|---|
About the Gear Train Simulator
Free interactive gear train simulator. Drag gears so they snap and mesh, spin the driver by hand or with a motor, change tooth counts, and see gear ratio, RPM, direction and torque of every gear. Built for engineering, the gear train simulator runs instantly in your browser: change a setting or drag an object and the result updates at once, so you learn by trying things out rather than only reading about them.
Drag gears together to mesh them, then see speed and torque change through the train. Use it to explore engineering ideas at your own pace, then check what you found against the key ideas further down this page.
How to use the Gear Train Simulator
- Use the controls to change Motor speed, Input torque. The simulation reacts instantly.
- Press "Motor on", "Reset" to start, reset or change what is happening.
- Where you see a glowing handle, object, weight or atom, drag it with your mouse or finger. Everything responds in real time.
- Watch the readouts and graphs update as you experiment, and compare what you see with the key ideas below.
Things to try
- Drag the small gear next to the big one until it snaps into mesh.
- Press Motor, then change the teeth of the big gear and watch its speed and torque readouts.
- Add the third gear in a chain and check which way each gear turns.
- Grab the driver gear and spin it by hand.
Key ideas you can learn
- Meshing gears turn in opposite directions.
- Gear ratio = driven teeth ÷ driver teeth. A bigger driven gear means slower speed but more torque.
- Power (torque × speed) stays the same through ideal gears.
Where this is used in the real world
Gears are in cars, bicycles, clocks, wind turbines, robots and every machine that needs to change speed or torque. Engineers pick tooth counts to get the right ratio.
Who is this simulation for?
Engineering and technology students, makers, robotics clubs and teachers of design and technology. It gives a hands-on feel for how machines behave before you build a real one.
For teachers: project it on the board, let students predict what will happen, then run it together. For students: change one thing at a time and write down what changes.
Frequently asked questions
How do you calculate gear ratio?
Divide the number of teeth on the driven gear by the number of teeth on the driving gear. A ratio of 3:1 means the driver turns three times for each turn of the driven gear.
Why do gears reverse direction?
Where two gears mesh, their teeth push in opposite directions, so each gear spins the opposite way to its neighbour. An idler gear between them restores the original direction.
Is the Gear Train Simulator free to use?
Yes. It is completely free, with no signup, no download and no ads inside the simulation. It runs in your web browser.
Does the Gear Train Simulator work on a phone or tablet?
Yes. It uses touch as well as the mouse, so you can drag objects with your finger. A larger screen makes the controls easier to see.