How do you calculate average cycling speed?
Distance divided by time: ride 30 miles in 2 hours and your average is 15 mph. The other two directions are the same triangle rearranged — time is distance ÷ speed, distance is speed × time. The only place people go wrong is units (minutes hiding inside hours) and clocks (more on that below) — which is what the calculator above is for.
How long does it take to bike 10, 20 or 50 miles?
The question people actually type, answered at three realistic solo averages:
| Distance | at 12 mph | at 15 mph | at 18 mph |
|---|---|---|---|
| 5 miles | 25:00 | 20:00 | 16:40 |
| 10 miles | 50:00 | 40:00 | 33:20 |
| 20 miles | 1:40:00 | 1:20:00 | 1:06:40 |
| 30 miles | 2:30:00 | 2:00:00 | 1:40:00 |
| 50 miles | 4:10:00 | 3:20:00 | 2:46:40 |
| 100 miles | 8:20:00 | 6:40:00 | 5:33:20 |
Riding time only, h:mm:ss. 12 mph is a relaxed cruise, 15 a regular solo rider on mixed roads, 18 a fit rider working — see the watts table below for what each costs.
Speed to pace: mph, km/h and minutes per mile
Runners think in pace, cyclists in speed, and half the world in kilometers. The same rows, three ways:
| mph | km/h | Minutes per mile |
|---|---|---|
| 10 | 16.1 | 6:00 |
| 12 | 19.3 | 5:00 |
| 15 | 24.1 | 4:00 |
| 18 | 29.0 | 3:20 |
| 20 | 32.2 | 3:00 |
| 25 | 40.2 | 2:24 |
Pace = 60 ÷ mph. The calculator's km toggle converts the value you typed, not just the label.
What speed do I need to finish in my target time?
The reverse question is the one that matters the week before an event. Required average speeds, computed by the calculator:
| Event | Target time → required average | |||
|---|---|---|---|---|
| Century (100 mi) | 5:00:00 → 20.0 mph | 6:00:00 → 16.7 mph | 7:00:00 → 14.3 mph | 8:00:00 → 12.5 mph |
| Metric century (100 km) | 3:30:00 → 17.8 mph | 4:00:00 → 15.5 mph | 5:00:00 → 12.4 mph | 6:00:00 → 10.4 mph |
| 40k time trial | 1:00:00 → 24.9 mph | 1:10:00 → 21.3 mph | 1:20:00 → 18.6 mph | 1:30:00 → 16.6 mph |
Riding averages — add your realistic stop time on top (a century's rest stops routinely add 30–60 minutes of clock). For hilly events, the climb time calculator prices the climbs separately.
Your bike computer auto-pauses at stoplights and snack stops, so the "average speed" it reports is moving average — often 1–2 mph prettier than reality. Event clocks and your arrival time don't pause. When you plan with this calculator, decide which clock you mean: use moving average to compare fitness, elapsed average to promise anyone you'll be somewhere by 3 pm.
How much do stops change the elapsed time?
More than most plans allow for. A century ridden at a 16 mph moving average takes 6:15:00 on the bike; add 45 minutes of rest stops, mechanicals and photos — a modest day — and the clock reads 7:00:00, an elapsed average of 14.3 mph. Nothing about your fitness changed; the number you'd have to tell someone picking you up did. That gap is the whole difference between the average your computer shows and the one that gets you to the finish before the cutoff, and it's why event planning starts from elapsed time and works backward.
What's a good average cycling speed?
Short answer: it depends on terrain, wind, traffic lights, and whether you had wheels to draft — a solo 16 mph into wind is a stronger ride than 19 mph in a group. That said, for solo riding on mostly flat roads, here are fair bands — priced in the watts they actually cost, from the same physics engine as our power ↔ speed calculator:
| Solo average | Steady watts it takes | Typical rider |
|---|---|---|
| 12 mph | ~51 W | New riders, casual cruising |
| 15 mph | ~86 W | Regular riders, solo |
| 18 mph | ~135 W | Fit riders putting in miles |
| 21 mph | ~201 W | Strong riders, race pace territory |
Flat road, still air, hoods position, 165 lb rider + 19 lb bike. Group riding cuts the wattage 25–40% at the same speed — which is why group averages don't compare to solo ones.
Riding a century at 18 mph instead of 16 saves 42 minutes (5:33:20 vs 6:15:00). But those two mph raise the steady power required from ~100 to ~135 W — 35% more, held for five and a half hours. Air resistance grows with the cube of speed: the clock is linear, the effort isn't. That's the real trade every "can I finish in six hours?" plan should be built on.
How fast do professional cyclists ride?
Grand Tour stages average around 25 mph (40 km/h) over five hours, and time trials run past 30. The physics engine explains how: a solo rider on the hoods needs about 322 W to hold 25 mph on the flat, which is why the peloton does it in a bunch where most riders spend a fraction of that — and a 30 mph time trial on aero bars costs roughly 398 W, which is a world-class hour. The comparison to draw isn't with your solo average; it's with your watts. A 200 W rider who sits in a fast group all day will post a pro-looking speed and a very ordinary power file, and the power file is the one that describes the rider.
Planning a ride you haven't done before
Work backward: pick the elapsed time you want, subtract realistic stops (10 minutes per hour of riding is typical for social rides), and the calculator gives the moving average you need. Then gut-check that speed against the watts table above and your last few solo rides. If the required average is 2 mph above anything you've held recently, the fix isn't optimism — it's starting earlier, drafting smarter, or picking a flatter route.