Bicycle Gear Ratio & Speed Calculator
Enter your chainring and cassette teeth counts, pick your wheel size, and drag the cadence slider to see your speed for every gear combination - sorted slowest to fastest. Nothing uploaded.
Chainrings
Cadence
Speed unit
Learn more: gear ratios, cadence, and drivetrain planning
Gear ratio is chainring teeth divided by sprocket teeth
The ratio tells you how many turns the rear wheel makes for one turn of the pedals. A 50-tooth chainring driving an 11-tooth sprocket gives 50 / 11 = 4.55, so the wheel goes round four and a half times per pedal stroke. That is the hardest gear on a typical road bike.
At the other end, a 34-tooth ring on a 32-tooth sprocket gives 34 / 32 = 1.06, barely more than one wheel turn per stroke. Nothing else about the bike changes this number. Tire choice and rider weight affect how hard the gear feels, but the ratio itself only depends on the two teeth counts.
Turning a ratio into a speed
Speed is ratio multiplied by wheel circumference multiplied by cadence. With a 3.0 ratio on a 700c wheel (2105 mm circumference) at 90 rpm, that works out to 3.0 x 2105 mm x 90 x 60 minutes, or 34.1 km/h.
Cadence enters the sum as a straight multiplier, so the relationship is linear. In that same 3.0 gear, every extra 10 rpm adds 3.8 km/h. Dragging the slider from 60 to 120 rpm doubles every speed in the chart at once.
The chart sorts every chainring and sprocket pairing from slowest to fastest rather than grouping them by ring. On a double chainring that mixes the two rings together, which is the quickest way to spot gears that overlap and duplicate each other.
Gear range, and a shortcut for working it out
The range ratio stat is your top speed divided by your lowest speed at the same cadence. The default setup here (50/34 rings, an 11 to 32 cassette, 700c wheels) runs from 12.1 km/h to 51.7 km/h at 90 rpm, a range of 4.27x.
You can get to that number without a calculator by multiplying the ring spread by the cassette spread. For the default setup that is (50 / 34) x (32 / 11) = 4.28, a hair off the 4.27 shown on screen only because the stat rounds the two speeds to one decimal before dividing them. On a single-ring drivetrain the first term drops out, so the range is simply the cassette spread.
Some real numbers for comparison, all at 700c and 90 rpm. A 50/34 compact with an 11-28 cassette gives 3.75x. The same rings with an 11-34 give 4.54x. A 53/39 standard double with 11-28 gives only 3.47x, which is why that setup has a reputation for being unkind on steep climbs. A single 40-tooth ring with an 11-42 cassette gives 3.82x.
Wider is not automatically better. A big range spread over the same number of sprockets means bigger jumps between adjacent gears, and those jumps are what make it awkward to hold a steady cadence on rolling ground.
What wheel size does and does not change
The wheel dropdown holds five nominal circumferences: 700c road at 2105 mm, 29 inch at 2209 mm, 27.5 inch at 2079 mm, 26 inch at 1952 mm, and 20 inch folding at 1590 mm. Swapping between them rescales every speed in the chart.
A 34x32 gear at 90 rpm gives 12.1 km/h on 700c, 12.7 km/h on a 29er and 11.2 km/h on a 26 inch wheel. The gear ratio is identical in all three cases. Only the ground covered per wheel turn differs.
Because the wheel multiplies every gear by the same amount, it cancels out of the range ratio entirely. Wheel size moves your whole gearing up or down. It never widens or narrows it. There is no custom circumference field, so pick the nearest preset and treat the speeds as close rather than exact, since a real rolling circumference shifts a little with tyre width and pressure.
FAQ
What is gear ratio on a bicycle?
Gear ratio is the number of rear wheel revolutions per pedal stroke, found by dividing the chainring teeth by the rear sprocket teeth. A 50-tooth chainring with an 11-tooth sprocket gives a ratio of 4.55, so the wheel turns 4.55 times for every turn of the pedals.
How do I calculate my bike speed from cadence?
Speed = gear ratio x wheel circumference x cadence. With a gear ratio of 3.0, a 700c wheel (2105 mm circumference) and a cadence of 90 rpm: 3.0 x 2105 mm x 90 x 60 = 34.1 km/h. The calculator runs that sum for every gear combination at once.
What is a good gear range ratio for a road bike?
Modern road doubles land between roughly 3.5x and 4.5x. A 50/34 compact with an 11-28 cassette gives 3.75x, the same rings with an 11-34 give 4.54x, and a 53/39 with an 11-28 gives 3.47x. Hillier routes are easier with a wider range, at the cost of bigger gaps between gears.