Bike gear ratio calculator &cChart

Bike gear ratio calculator and chart for road and MTB drivetrains

Your gear ratio is what stands between your legs and your speed. Too tall a gear on a climb and you grind to a halt; too short a gear on a flat road and you spin out well below your potential. Whether you are setting up a road bike for a hilly sportive, fine-tuning a 1x MTB drivetrain, or simply curious about the maths behind your chainring and sprocket, this page gives you an instant calculator, a full reference chart, and a plain-English explanation of how it all works.

1. What is bike gear ratio?

Your bike's gear ratio is simply the number of teeth on your chainring divided by the number of teeth on your sprocket. It tells you how many times your rear wheel turns for every single turn of your cranks — and, combined with your wheel size, it determines exactly how far you travel with each pedal stroke.

A high gear ratio (big chainring, small sprocket) covers more distance per pedal stroke but demands more force, ideal for flat roads and descents. A low gear ratio (small chainring, big sprocket) covers less distance but requires far less effort, which is exactly what you want on a steep climb.

To remember: gear ratio = chainring teeth ÷ sprocket teeth. A 52-tooth chainring with a 12-tooth sprocket gives a ratio of 4.33 — for every crank turn, the rear wheel turns 4.33 times.

Did you know? A 700c road wheel and a 29-inch MTB wheel share exactly the same 622 mm bead seat diameter. The "29 inch" and "700" options in the calculator below therefore use the same base circumference — only the tyre width changes the final figure.

2. Bike gear ratio & speed calculator

Select your wheel size, tyre width, chainring, sprocket and pedalling cadence below — the calculator instantly updates your resulting speed in km/h.

Wheel characteristics

Point of attention: this calculation assumes zero drivetrain loss and a constant cadence. Real-world speed will vary slightly with tyre pressure, road surface and wind resistance.

3. How the calculation works

The formula behind the calculator above is straightforward once broken into four steps. Here is a worked example for a 700 mm wheel fitted with a 25C tyre, a 52-tooth chainring and a 12-tooth sprocket, at a cadence of 70 rpm:

A. Wheel + tyre circumference = (622 + 50) × π ≈ 2,111 mm

B. Gear ratio = 52 ÷ 12 = 4.33

C. Distance travelled per crank turn = 2,111 mm × 4.33 ≈ 9,141 mm, i.e. 9.14 meters

D. At a cadence of 70 rpm, speed = (9.14 × 70 × 60) / 1,000 ≈ 38.4 km/h

To keep in mind: this formula works for every chainring shape (round or oval) and every drivetrain brand — Shimano, SRAM, Campagnolo, Rotor, TA, Stronglight and others all follow the same mechanical principle.

For a precise real-world measurement, roll your wheel exactly one full turn on the ground and measure the distance travelled — this accounts for tyre compression under load, which the theoretical formula does not.

4. Wheel & tyre circumference calculator

Need the circumference of a specific wheel and tyre combination on its own, without the full gear ratio calculation? Use the quick calculator below.

Looking for a full reference chart across every wheel size, in both millimetres and inches? See our complete wheel circumference guide.

5. Road bike gear ratio chart

The tables below give the theoretical distance travelled per crank turn (in metres) for a 700 mm road wheel, without accounting for tyre thickness, across the full range of common chainring and sprocket combinations.

Typical road bike examples: a 50x17 combination suits general rolling terrain (around 4.90 m per crank turn), while a compact 34x28 is a common climbing gear (around 1.90 m per crank turn) and a 53x11 or 55x11 is used for flat-out sprints or fast time trials.

Chainrings 20 to 30 teeth

Chainring 20–30 teeth — distance per crank turn (metres)
Sprocket \ Chainring	20T	21T	22T	23T	24T	25T	26T	27T	28T	29T	30T
11T	4.00	4.20	4.40	4.60	4.80	5.00	5.20	5.40	5.59	5.79	5.99
12T	3.66	3.85	4.03	4.21	4.40	4.58	4.76	4.95	5.13	5.31	5.50
13T	3.38	3.55	3.72	3.89	4.06	4.23	4.40	4.57	4.73	4.90	5.07
14T	3.14	3.30	3.45	3.61	3.77	3.92	4.08	4.24	4.40	4.55	4.71
15T	2.93	3.08	3.22	3.37	3.52	3.66	3.81	3.96	4.10	4.25	4.40
16T	2.75	2.88	3.02	3.16	3.30	3.43	3.57	3.71	3.85	3.98	4.12
17T	2.59	2.72	2.84	2.97	3.10	3.23	3.36	3.49	3.62	3.75	3.88
18T	2.44	2.56	2.69	2.81	2.93	3.05	3.17	3.30	3.42	3.54	3.66
19T	2.31	2.43	2.55	2.66	2.78	2.89	3.01	3.12	3.24	3.35	3.47
20T	2.20	2.31	2.42	2.53	2.64	2.75	2.86	2.97	3.08	3.19	3.30
21T	2.09	2.20	2.30	2.41	2.51	2.62	2.72	2.83	2.93	3.04	3.14
22T	2.00	2.10	2.20	2.30	2.40	2.50	2.60	2.70	2.80	2.90	3.00
23T	1.91	2.01	2.10	2.20	2.29	2.39	2.48	2.58	2.68	2.77	2.87
24T	1.83	1.92	2.01	2.11	2.20	2.29	2.38	2.47	2.56	2.66	2.75
25T	1.76	1.85	1.93	2.02	2.11	2.20	2.29	2.37	2.46	2.55	2.64
26T	1.69	1.78	1.86	1.94	2.03	2.11	2.20	2.28	2.37	2.45	2.54
27T	1.63	1.71	1.79	1.87	1.95	2.04	2.12	2.20	2.28	2.36	2.44
28T	1.57	1.65	1.73	1.81	1.88	1.96	2.04	2.12	2.20	2.28	2.35
29T	1.52	1.59	1.67	1.74	1.82	1.89	1.97	2.05	2.12	2.20	2.27
30T	1.47	1.54	1.61	1.69	1.76	1.83	1.90	1.98	2.05	2.12	2.20
31T	1.42	1.49	1.56	1.63	1.70	1.77	1.84	1.91	1.99	2.06	2.13
32T	1.37	1.44	1.51	1.58	1.65	1.72	1.79	1.85	1.92	1.99	2.06
33T	1.33	1.40	1.47	1.53	1.60	1.67	1.73	1.80	1.86	1.93	2.00
34T	1.29	1.36	1.42	1.49	1.55	1.62	1.68	1.75	1.81	1.87	1.94
35T	1.26	1.32	1.38	1.44	1.51	1.57	1.63	1.70	1.76	1.82	1.88
36T	1.22	1.28	1.34	1.40	1.47	1.53	1.59	1.65	1.71	1.77	1.83
37T	1.19	1.25	1.31	1.37	1.43	1.49	1.54	1.60	1.66	1.72	1.78
38T	1.16	1.21	1.27	1.33	1.39	1.45	1.50	1.56	1.62	1.68	1.74
39T	1.13	1.18	1.24	1.30	1.35	1.41	1.47	1.52	1.58	1.63	1.69
40T	1.10	1.15	1.21	1.26	1.32	1.37	1.43	1.48	1.54	1.59	1.65

Chainrings 31 to 40 teeth

Chainring 31–40 teeth — distance per crank turn (metres)
Sprocket \ Chainring	31T	32T	33T	34T	35T	36T	37T	38T	39T	40T
11T	6.19	6.39	6.59	6.79	6.99	7.19	7.39	7.59	7.79	7.99
12T	5.68	5.86	6.04	6.23	6.41	6.59	6.78	6.96	7.14	7.33
13T	5.24	5.41	5.58	5.75	5.92	6.09	6.26	6.42	6.59	6.76
14T	4.87	5.02	5.18	5.34	5.50	5.65	5.81	5.97	6.12	6.28
15T	4.54	4.69	4.84	4.98	5.13	5.28	5.42	5.57	5.71	5.86
16T	4.26	4.40	4.53	4.67	4.81	4.95	5.08	5.22	5.36	5.50
17T	4.01	4.14	4.27	4.40	4.53	4.65	4.78	4.91	5.04	5.17
18T	3.79	3.91	4.03	4.15	4.27	4.40	4.52	4.64	4.76	4.88
19T	3.59	3.70	3.82	3.93	4.05	4.16	4.28	4.40	4.51	4.63
20T	3.41	3.52	3.63	3.74	3.85	3.96	4.07	4.18	4.29	4.40
21T	3.24	3.35	3.45	3.56	3.66	3.77	3.87	3.98	4.08	4.19
22T	3.10	3.20	3.30	3.40	3.50	3.60	3.70	3.80	3.90	4.00
23T	2.96	3.06	3.15	3.25	3.34	3.44	3.54	3.63	3.73	3.82
24T	2.84	2.93	3.02	3.11	3.21	3.30	3.39	3.48	3.57	3.66
25T	2.73	2.81	2.90	2.99	3.08	3.17	3.25	3.34	3.43	3.52
26T	2.62	2.71	2.79	2.87	2.96	3.04	3.13	3.21	3.30	3.38
27T	2.52	2.61	2.69	2.77	2.85	2.93	3.01	3.09	3.17	3.26
28T	2.43	2.51	2.59	2.67	2.75	2.83	2.90	2.98	3.06	3.14
29T	2.35	2.43	2.50	2.58	2.65	2.73	2.80	2.88	2.96	3.03
30T	2.27	2.34	2.42	2.49	2.56	2.64	2.71	2.78	2.86	2.93
31T	2.20	2.27	2.34	2.41	2.48	2.55	2.62	2.69	2.77	2.84
32T	2.13	2.20	2.27	2.34	2.40	2.47	2.54	2.61	2.68	2.75
33T	2.06	2.13	2.20	2.26	2.33	2.40	2.46	2.53	2.60	2.66
34T	2.00	2.07	2.13	2.20	2.26	2.33	2.39	2.46	2.52	2.59
35T	1.95	2.01	2.07	2.14	2.20	2.26	2.32	2.39	2.45	2.51
36T	1.89	1.95	2.01	2.08	2.14	2.20	2.26	2.32	2.38	2.44
37T	1.84	1.90	1.96	2.02	2.08	2.14	2.20	2.26	2.32	2.38
38T	1.79	1.85	1.91	1.97	2.02	2.08	2.14	2.20	2.26	2.31
39T	1.75	1.80	1.86	1.92	1.97	2.03	2.09	2.14	2.20	2.25
40T	1.70	1.76	1.81	1.87	1.92	1.98	2.03	2.09	2.14	2.20

Chainrings 41 to 50 teeth

Chainring 41–50 teeth — distance per crank turn (metres)
Sprocket \ Chainring	41T	42T	43T	44T	45T	46T	47T	48T	49T	50T
11T	8.19	8.39	8.59	8.79	8.99	9.19	9.39	9.59	9.79	9.99
12T	7.51	7.69	7.88	8.06	8.24	8.43	8.61	8.79	8.98	9.16
13T	6.93	7.10	7.27	7.44	7.61	7.78	7.95	8.12	8.28	8.45
14T	6.44	6.59	6.75	6.91	7.07	7.22	7.38	7.54	7.69	7.85
15T	6.01	6.15	6.30	6.45	6.59	6.74	6.89	7.03	7.18	7.33
16T	5.63	5.77	5.91	6.04	6.18	6.32	6.46	6.59	6.73	6.87
17T	5.30	5.43	5.56	5.69	5.82	5.95	6.08	6.21	6.34	6.46
18T	5.01	5.13	5.25	5.37	5.50	5.62	5.74	5.86	5.98	6.11
19T	4.74	4.86	4.97	5.09	5.21	5.32	5.44	5.55	5.67	5.78
20T	4.51	4.62	4.73	4.84	4.95	5.06	5.17	5.28	5.39	5.50
21T	4.29	4.40	4.50	4.61	4.71	4.81	4.92	5.02	5.13	5.23
22T	4.10	4.20	4.30	4.40	4.50	4.60	4.70	4.80	4.90	5.00
23T	3.92	4.01	4.11	4.20	4.30	4.40	4.49	4.59	4.68	4.78
24T	3.75	3.85	3.94	4.03	4.12	4.21	4.30	4.40	4.49	4.58
25T	3.60	3.69	3.78	3.87	3.96	4.04	4.13	4.22	4.31	4.40
26T	3.47	3.55	3.64	3.72	3.80	3.89	3.97	4.06	4.14	4.23
27T	3.34	3.42	3.50	3.58	3.66	3.74	3.83	3.91	3.99	4.07
28T	3.22	3.30	3.38	3.45	3.53	3.61	3.69	3.77	3.85	3.92
29T	3.11	3.18	3.26	3.33	3.41	3.49	3.56	3.64	3.71	3.79
30T	3.00	3.08	3.15	3.22	3.30	3.37	3.44	3.52	3.59	3.66
31T	2.91	2.98	3.05	3.12	3.19	3.26	3.33	3.40	3.47	3.55
32T	2.82	2.88	2.95	3.02	3.09	3.16	3.23	3.30	3.37	3.43
33T	2.73	2.80	2.86	2.93	3.00	3.06	3.13	3.20	3.26	3.33
34T	2.65	2.72	2.78	2.84	2.91	2.97	3.04	3.10	3.17	3.23
35T	2.57	2.64	2.70	2.76	2.83	2.89	2.95	3.01	3.08	3.14
36T	2.50	2.56	2.63	2.69	2.75	2.81	2.87	2.93	2.99	3.05
37T	2.44	2.50	2.55	2.61	2.67	2.73	2.79	2.85	2.91	2.97
38T	2.37	2.43	2.49	2.55	2.60	2.66	2.72	2.78	2.83	2.89
39T	2.31	2.37	2.42	2.48	2.54	2.59	2.65	2.71	2.76	2.82
40T	2.25	2.31	2.36	2.42	2.47	2.53	2.58	2.64	2.69	2.75

Chainrings 51 to 60 teeth

Chainring 51–60 teeth — distance per crank turn (metres)
Sprocket \ Chainring	51T	52T	53T	54T	55T	56T	57T	58T	59T	60T
11T	10.19	10.39	10.59	10.79	10.99	11.19	11.39	11.59	11.79	11.99
12T	9.34	9.52	9.71	9.89	10.07	10.26	10.44	10.62	10.81	10.99
13T	8.62	8.79	8.96	9.13	9.30	9.47	9.64	9.81	9.98	10.14
14T	8.01	8.16	8.32	8.48	8.63	8.79	8.95	9.11	9.26	9.42
15T	7.47	7.62	7.77	7.91	8.06	8.21	8.35	8.50	8.65	8.79
16T	7.01	7.14	7.28	7.42	7.56	7.69	7.83	7.97	8.11	8.24
17T	6.59	6.72	6.85	6.98	7.11	7.24	7.37	7.50	7.63	7.76
18T	6.23	6.35	6.47	6.59	6.72	6.84	6.96	7.08	7.20	7.33
19T	5.90	6.02	6.13	6.25	6.36	6.48	6.59	6.71	6.83	6.94
20T	5.60	5.71	5.82	5.93	6.04	6.15	6.26	6.37	6.48	6.59
21T	5.34	5.44	5.55	5.65	5.76	5.86	5.97	6.07	6.18	6.28
22T	5.10	5.20	5.30	5.40	5.50	5.59	5.69	5.79	5.89	5.99
23T	4.87	4.97	5.06	5.16	5.26	5.35	5.45	5.54	5.64	5.73
24T	4.67	4.76	4.85	4.95	5.04	5.13	5.22	5.31	5.40	5.50
25T	4.48	4.57	4.66	4.75	4.84	4.92	5.01	5.10	5.19	5.28
26T	4.31	4.40	4.48	4.57	4.65	4.73	4.82	4.90	4.99	5.07
27T	4.15	4.23	4.31	4.40	4.48	4.56	4.64	4.72	4.80	4.88
28T	4.00	4.08	4.16	4.24	4.32	4.40	4.47	4.55	4.63	4.71
29T	3.87	3.94	4.02	4.09	4.17	4.24	4.32	4.40	4.47	4.55
30T	3.74	3.81	3.88	3.96	4.03	4.10	4.18	4.25	4.32	4.40
31T	3.62	3.69	3.76	3.83	3.90	3.97	4.04	4.11	4.18	4.25
32T	3.50	3.57	3.64	3.71	3.78	3.85	3.92	3.98	4.05	4.12
33T	3.40	3.46	3.53	3.60	3.66	3.73	3.80	3.86	3.93	4.00
34T	3.30	3.36	3.43	3.49	3.56	3.62	3.68	3.75	3.81	3.88
35T	3.20	3.27	3.33	3.39	3.45	3.52	3.58	3.64	3.71	3.77
36T	3.11	3.17	3.24	3.30	3.36	3.42	3.48	3.54	3.60	3.66
37T	3.03	3.09	3.15	3.21	3.27	3.33	3.39	3.45	3.50	3.56
38T	2.95	3.01	3.07	3.12	3.18	3.24	3.30	3.35	3.41	3.47
39T	2.87	2.93	2.99	3.04	3.10	3.16	3.21	3.27	3.33	3.38
40T	2.80	2.86	2.91	2.97	3.02	3.08	3.13	3.19	3.24	3.30

6. MTB gear ratio & 1x drivetrains

Mountain bike gearing has changed radically over the last decade. Where road bikes still commonly run two chainrings, most modern MTBs — from XC race bikes to enduro rigs — now run a single chainring paired with a wide-range cassette.

The number of sprockets on a bike cassette has quickly increased in recent years, from 5-speed to 12-speed today. This progress has allowed a much wider spread of gears from a single chainring. It is now common to find a cassette with a smallest sprocket of just 10 teeth and a largest sprocket of 50 or 51 teeth — a range wide enough to replace what used to require two or three chainrings.

Improvements in chain flexibility and rear derailleur cage design have made this possible: a single chainring with a 12-speed cassette can now cover the same gear range as an older triple-chainring drivetrain, while removing the front derailleur, the second shifter and one or two chainrings — a meaningful weight saving.

Typical 1x MTB setup: a 32-tooth chainring paired with a 10-51 tooth cassette gives a climbing gear as low as 32x51 (around 0.62 m per crank turn) up to a top gear of 32x10 (around 3.15 m per crank turn) — a huge range from a single ring.

The calculation method is exactly the same as for a road bike (chainring teeth ÷ sprocket teeth, multiplied by wheel and tyre circumference) — simply plug your MTB's 29-inch, 27.5-inch or 26-inch wheel size, tyre width, chainring and sprocket into the calculator above.

7. Which gear ratio for your riding style?

Profile	Typical gear ratio	Why
Climbing / mountainous terrain	Compact 34x28-32	Short gear ratio, spares your knees on steep, sustained gradients
Rolling / mixed sportive terrain	50x17 to 34x25	Versatile range for varied gradients over a long ride
Time trial / triathlon	55x11 to 53x11	Tall gear ratio for maximum speed on flat, fast courses
MTB XC / enduro	32x50 (1x12)	Wide-range single chainring for climbing grip and mechanical simplicity
Commuting / everyday riding	46x16 to 40x20	Comfortable, steady effort with less strain over frequent short rides

8. Gear ratio limits in competition

To limit the power output of younger riders, junior categories in road racing have historically been subject to gear ratio restrictions. In France, for example, the minimes category has been limited to a maximum of 7.01 metres per crank turn — equivalent to a 46-tooth chainring with a 14-tooth sprocket — while cadets have been limited to 7.62 metres, equivalent to a 50-tooth chainring with a 14-tooth sprocket. These restrictions are typically lifted once riders move into senior UCI categories.

Some real-world examples of gear ratios used by professional cyclists: a 36x28 combination for the ascent of Mont Ventoux, versus a 55x11 or 60x11 combination for a flat individual time trial.

Historical example — 2020 World Time Trial Championship: at the 2020 UCI Road World Championships in Imola, Filippo Ganna won the individual time trial riding a 60x11 gear, covering 31.7 km at an average speed of 57.6 km/h. According to the chart above, that gear ratio covers 11.99 metres per crank turn — meaning his pedalling cadence to hold that average speed worked out at roughly 80 rpm.

9. FAQ — Bike gear ratio calculator & chart

How do I calculate my bike's gear ratio?

Divide the number of teeth on your chainring by the number of teeth on your sprocket. Multiply the result by your wheel and tyre circumference to get the distance covered per crank turn, then multiply by your cadence to get your speed. Our calculator above does this instantly for any wheel size and drivetrain combination.

What is a good gear ratio for a road bike?

Most road cyclists ride between a 2.5:1 ratio (compact 34x28 for climbing) and a 5:1 ratio (53x11 for fast descents or flat sprints). A 50x17 or similar mid-range combination suits general rolling terrain.

What gear ratio is best for climbing?

For steep or sustained climbs, a low gear ratio is best: a small chainring (34 teeth or less) paired with a large sprocket (28 teeth or more) reduces the effort needed per pedal stroke, at the cost of a lower top speed.

What's the difference between gear ratio and gear inches?

Gear ratio is a simple, unitless number (chainring teeth divided by sprocket teeth) and does not account for wheel size. Gear inches multiplies the gear ratio by the wheel diameter in inches, which lets you compare the effective gearing of bikes with different wheel sizes on a like-for-like basis.

Do MTB and road bikes use the same gear ratio calculation?

The calculation method is identical, but the typical values differ. Modern MTBs generally use a single 30-34 tooth chainring paired with a wide-range 10-51 or 10-52 tooth cassette, while road bikes typically use two chainrings (50/34 or 52/36) with a narrower-range cassette.

What gear ratio do professional cyclists use?

It depends entirely on the terrain and discipline. Pro climbers have used ratios as low as 36x28 on mountain stages such as Mont Ventoux, while time trial specialists have used ratios as high as 55x11 or 60x11 to maximise speed on flat, fast courses.

See our road & MTB cassettes and chainrings →

Bike gear ratio calculation and gear ratio chart