Travel, Auto & Lifestyle
Bike Gear Calculator
Bike Gear Calculator is a browser-based calculator tool on CalcToolsBase. Free, browser-based bike gear tool. Enter chainring, cog, wheel diameter, and cadence to get gear ratio, development, gear inches, and speed. To use it, enter your values and view the result directly in your browser — no signup and nothing to install.
From your chainring teeth, rear cog teeth, wheel diameter in mm and cadence in RPM, Bike Gear Calculator computes your gear ratio, development, gear inches and speed via the gear-ratio formula (chainring ÷ cog) with your wheel size and cadence. No accounts, no uploads — just an instant way to work out your bike gearing.
Gear and speed estimates depend on actual wheel rollout, tire size, cadence, terrain, and drivetrain setup. Everything runs locally in your browser and nothing you enter is uploaded.
About this tool
The Bike Gear Calculator is a lightweight, browser-based calculator for when you need to work out your bike gearing. It takes your chainring teeth, rear cog teeth, wheel diameter in mm and cadence in RPM, applies the gear-ratio formula (chainring ÷ cog) with your wheel size and cadence, and reports your gear ratio, development, gear inches and speed clearly. Nothing is uploaded and nothing is saved between visits.
How to use
- Enter the chainring teeth at the front.
- Enter the rear cog teeth you are using.
- Enter the wheel diameter in millimetres and your cadence.
- Press Calculate to see ratio, development, and speed.
Why use the Bike Gear Calculator
Instant
Each result is worked out on your device the moment you press Calculate.
Private
The numbers you enter stay in your browser and are never uploaded.
Free
No signup and no paywall to use any tool in this set.
Works offline
Once the page has loaded it keeps working on a weak or dropped connection.
Clear units
Inputs and outputs name their units so you know exactly what you are reading.
Honest by design
Uses simplified browser-side formulas for estimates; real speed varies with wheel rollout, tyre size, cadence and your drivetrain setup.
Common uses
Bike Gear when choosing a chainring and cassette
Bike Gear when fine-tuning your cadence
Bike Gear for setting up a new drivetrain
Bike Gear when comparing 1x and 2x setups
Bike Gear for working out gear inches
Bike Gear for comparing gear ratios
Technical notes
Bike Gear Calculator computes gear ratio and gear-inches from the chainring and sprocket tooth counts.
Speed assumes the wheel size and cadence you enter; real speed varies with tyre size, drivetrain losses and conditions.
All arithmetic runs in your browser using double-precision floating point, so extreme inputs may show tiny rounding differences.
Worked example
A 50-tooth chainring with a 14-tooth sprocket gives a ratio of 50 ÷ 14 = 3.57 — one pedal turn drives 3.57 wheel turns.
FAQ
Does cadence affect the speed shown?
Yes. Speed is development per revolution times your cadence, so a higher RPM at the same gear gives a higher speed. The result names the cadence used.
What is development in this tool?
Development is the distance the bike travels for one full pedal revolution, found by multiplying the gear ratio by the wheel circumference.
What wheel diameter should I enter?
Enter the effective rolling diameter in millimetres, including the tire. A common road value is about 700, which the tool uses for circumference.
What are gear inches?
Gear inches is a traditional measure equal to the gear ratio times the wheel diameter in inches. Bigger gear inches means a harder, faster gear.