Cycling Cadence Calculator - Cadence and Speed for Any Gear

Cycling cadence from speed, or speed from cadence

Twenty miles an hour in a 50x17 gear on 700x25C tires takes 87 rpm. This cycling cadence calculator works that out for any chainring, cog and wheel, in mph or km/h, and runs the other way too: type the rpm from your cadence sensor and read the speed. Next to the answer it shows the gear ratio, gear inches, how far the bike travels per crank turn, and, if you ask for it, the cog that would put you at a target cadence such as 90 rpm.

87 rpm

for 20 mph in a 50x17 gear on 700x25C wheels

89 rpm

average cadence of Grand Tour professionals on flat stages

71 rpm

the same riders' average on long mountain climbs

77.6 in

gear inches of a 50x17 on a 700x25C tire

Setting up the gear in six fields

What to work out - cadence from a speed you know, or speed from the rpm your sensor shows.
Speed unit - mph or km/h. Every speed in the result, the table included, follows this choice.
Speed or cadence - the number from your bike computer. A cadence of 87.5 is fine; type decimals with a dot.
Chainring and rear cog - the tooth counts stamped on them. Road compacts are usually 50 and 34, cassettes run from 11 up to 28-34.
Wheel and tire size - printed on the tire sidewall, such as 700x28C or 29x2.2. If yours is missing, pick the custom option and enter a measured circumference in millimeters.
Target cadence - optional, cadence mode only. Type the rpm you would like to hold and the calculator names the cog that gets you there. Then read the headline, the tiles and the table.

How rpm, teeth and tire size turn into speed

Each turn of the cranks turns the rear wheel chainring teeth divided by cog teeth times. A 50x17 gear has a ratio of 2.94, so one pedal stroke moves the wheel almost three revolutions, and on a 700x25C tire with a 2,105 mm circumference that is 6.19 m of road. Multiply by the rpm and by 60 and you have the distance per hour. At 90 rpm that comes to 33.4 km/h, or 20.8 mph.

American and British gearing charts often quote gear inches instead: the gear ratio times the wheel diameter in inches, a leftover from the high-wheel era when the pedals sat on the front hub. The 50x17 on a 700x25C works out to 77.6 gear inches. Riders who prefer meters call the distance per crank turn development or rollout. Both numbers describe the same thing, and the calculator prints both.

Cadence is the part you choose. The gear only fixes how much speed each revolution buys; how many revolutions you make per minute is up to your legs, which is why the same speed can be ridden at 70 rpm in a big gear or at 100 rpm in a small one.

Speed at 90 rpm in twelve common gears

Every row is on 700x25C tires (2,105 mm). The two columns on the right are the speed you ride if you hold 90 rpm in that gear, the cadence many coaches use as a reference for steady riding on the flat.

Gear	Ratio	Gear inches	Development	At 90 rpm
50x11	4.55	119.9	9.57 m	32.1 mph / 51.7 km/h
50x13	3.85	101.5	8.10 m	27.2 mph / 43.7 km/h
50x15	3.33	87.9	7.02 m	23.5 mph / 37.9 km/h
50x17	2.94	77.6	6.19 m	20.8 mph / 33.4 km/h
50x19	2.63	69.4	5.54 m	18.6 mph / 29.9 km/h
50x21	2.38	62.8	5.01 m	16.8 mph / 27.1 km/h
50x25	2.00	52.8	4.21 m	14.1 mph / 22.7 km/h
34x17	2.00	52.8	4.21 m	14.1 mph / 22.7 km/h
34x21	1.62	42.7	3.41 m	11.4 mph / 18.4 km/h
34x25	1.36	35.9	2.86 m	9.6 mph / 15.5 km/h
34x28	1.21	32.0	2.56 m	8.6 mph / 13.8 km/h
34x32	1.06	28.0	2.24 m	7.5 mph / 12.1 km/h

Two rows are identical on purpose. A 50x25 and a 34x17 share the ratio 2.00, so they give the same speed at the same rpm; the difference is only which cogs the chain is crossing. On a compact crankset that overlap is normal, and it is the reason a gear chart can list 22 combinations while offering far fewer distinct gears.

One gear, eight wheel sizes

The same 50x17 at the same 90 rpm, with only the wheel changing. Circumferences come from the CatEye chart that bike computers use.

Wheel and tire	Circumference	Gear inches	Speed at 90 rpm
700x23C	2,096 mm	77.3	20.7 mph
700x25C	2,105 mm	77.6	20.8 mph
700x28C	2,136 mm	78.7	21.1 mph
700x32C	2,155 mm	79.4	21.3 mph
29x2.2	2,298 mm	84.7	22.7 mph
27.5x2.25	2,182 mm	80.4	21.5 mph
26x2.10	2,068 mm	76.2	20.4 mph
20x1.75	1,515 mm	55.8	15.0 mph

Going from a 23 mm to a 32 mm road tire changes the speed by about 0.6 mph at the same rpm, less than three percent. A 20-inch wheel is a different story: the same gear is almost 6 mph slower, which is why folding bikes run much bigger chainrings.

Gearing facts riders tend to miss

Pros climb at a lower cadence than they ride on the flat. In the study by Lucia, Hoyos and Chicharro, Grand Tour riders averaged about 89 rpm on flat stages, 92 rpm in time trials and 71 rpm on long climbs. A low number on a climb is not automatically a mistake.

One cog is worth more at the small end. Going from an 11 to a 13 changes the speed at 90 rpm by almost 5 mph; going from a 25 to a 28 on the 34 ring changes it by about 1 mph. That is why cassettes have one-tooth steps at the top and big jumps at the bottom.

Tire pressure moves the circumference. A soft or heavily loaded tire rolls on a slightly shorter circumference than the chart says. Measuring one wheel turn on the floor, with you sitting on the bike, gives the number your speed sensor should use.

The cadence that feels easiest is not fixed. It changes with power, terrain and training. The bands in the result describe what riders do, not what you should do on a given day.

Riders who reach for a cadence number

New road riders check whether the gear they cruise in leaves them grinding at 60 rpm or spinning at 110. Riders without a cadence sensor read their rpm from the speed and the gear instead. People choosing a cassette look up which cog would let them hold 90 rpm at their usual speed before buying. Gravel and touring riders compare how a bigger tire changes the same gear. Indoor riders on a smart trainer use speed and rpm together to set a gear for an interval.

Cadence and gearing questions

What cadence should I ride at?

There is no single right number. Most trained road riders settle between 80 and 100 rpm on the flat, and lower on steep climbs. If the calculator shows you below 70 rpm in your usual cruising gear, an easier gear is worth trying.

How do I find my cadence without a sensor?

Count how many times one knee comes up in 15 seconds and multiply by four. Or enter your speed and gear here in cadence mode; the result is the rpm that gear and speed require.

Does this work for a stationary bike?

Only for a bike on a trainer with a real drivetrain and a real wheel or a virtual one set to a known circumference. A spin bike or an air bike has no chainring and cog to enter, and the speed it shows is its own estimate.

Why does the target cadence suggest a cog I do not have?

It works out the exact tooth count, often a fraction such as 17.7, and then names the real cogs on either side with the rpm each one gives. If both are on your cassette, pick the one closer to the cadence you like.

Is gear inches better than development?

Neither is better. Gear inches is the traditional figure in the United States and the UK; development in meters is common elsewhere. Multiply gear inches by 0.0798 to get development in meters.

Related tools

Bike Gear Calculator

Every gear of your chainrings and cassette in gear inches and speed, and two drivetrains compared - See the calculator

Running Cadence Calculator

Steps per minute from pace and step length, or from a 30-second count - See the calculator

Cycling Power Calculator

Watts needed for a speed, or the speed your watts give, with riding position and wind - See the calculator

Power Zones Calculator

The seven Coggan training zones in watts from your FTP - See the calculator

FTP Calculator

Functional threshold power from a 20-minute, ramp or 8-minute test - See the calculator

Average Speed Calculator

Speed from distance and time, or the time a ride will take - See the calculator

Speed Converter

mph, km/h and meters per second in both directions - See the calculator

Bike vs Car Calculator

What a commute costs by bike and by car - See the calculator