⏱️ Cycling Speed Calculator

How to Use This Target Speed Calculator

This calculator works backward from your goal. Instead of asking how fast you rode, it asks how fast you need to ride. Enter the event distance and the finish time you want, and it returns the exact average speed required, plus a halfway checkpoint so you can check your progress mid-ride.

The Formula

Required average speed is distance divided by goal time, nothing more. A 100-mile goal of 5 hours 30 minutes needs 100 / 5.5 = 18.18 mph, or 29.26 km/h. The pace per mile is the reciprocal: 5.5 x 60 / 100 = 3.3 minutes per mile, or 3:18. The halfway checkpoint is half the goal time: 2:45 at 50 miles. Simple, but most riders never do this math before an event, then wonder why the goal slipped away in the final third.

Worked Example: Sub-5:30 Century

Enter 100 miles and 5 hours 30 minutes. Goal time = 5.5 hours. Required speed = 100 / 5.5 = 18.18 mph. In metric: 100 miles = 160.934 km, so 160.934 / 5.5 = 29.26 km/h. Pace per mile = 330 minutes / 100 = 3.3 min/mi = 3:18. The 10 percent buffer target is 20.0 mph, which is the speed to aim for in training so race-day adversity still leaves the goal reachable. Halfway checkpoint: 2:45 elapsed at mile 50. Check the calculator and confirm each number.

Building a Buffer Into the Goal

Race day never matches the spreadsheet. Wind picks up, a mechanical costs four minutes, the course measures long. Experienced riders train for a speed about 10 percent faster than the goal requires, so the goal itself feels like a controlled effort rather than a maximal one. If your goal needs 18.2 mph, train until 20 mph feels like tempo, not a time trial. On the day, ride the first third slightly under the required average, not over it. Banking time early in a long ride almost always backfires; the energy you spend in mile 20 is missing in mile 85.

Drafting, E-Bikes, and Honest Numbers

Group riding changes the math. A well-organized paceline cuts the required solo effort by roughly 30 percent, which is why charity centuries with big groups produce times that surprise solo riders. If your goal is a solo time trial, train solo. E-bikes change it more: US Class 1 and 2 e-bikes assist to 20 mph, Class 3 to 28 mph, which makes a 20 mph average a cruise rather than a workout. Set the goal for the bike you will actually ride, and if the event bans e-bikes, make sure your training numbers come from your acoustic bike.

Second worked example: 40K time trial in 58:00

Enter 40 km and 58 minutes. Goal time = 58/60 = 0.9667 hours. Required speed = 40 / 0.9667 = 41.38 km/h, which is 25.71 mph. Pace per km = 58/40 = 1.45 min = 1:27 per km. Halfway checkpoint: 29:00 elapsed at 20 km. The 10 percent buffer target is 45.5 km/h, the speed to hit in training so race-day adversity still leaves the goal reachable. Compare with the century example: 18.18 mph for 5.5 hours versus 25.71 mph for 58 minutes. Shorter events demand far higher speeds, which is why time-trial training is all intensity while century training is all endurance.

Pacing a time trial

The math gives you the average; pacing delivers it. The fastest way to ride a time trial is nearly even splits with a slight negative second half: start 2 to 3 percent under the required average for the first quarter, ride the middle at target, then empty the tank in the final quarter. Starting too hard spikes lactate early and the fade costs more than the fast start gained; pacing research consistently shows even pacing beats heroic starts. On rolling courses, push 5 to 10 percent over target on climbs and recover 5 percent under on descents, since speed is cheapest where resistance is lowest. In the final 10 minutes, heart rate and perceived effort are the guides, not the average on the computer: if you finish feeling you could have gone 5 percent harder, you paced it right; if you blew up at two-thirds, you started too hard.

Common goal-speed mistakes

Mistake one is no buffer. Training exactly to the goal speed means race day needs perfection: no wind, no mechanical, no bad legs. Train 10 percent faster than the goal so the goal feels like a controlled effort. Mistake two is the wrong bike baseline. A 20 mph average on a road bike in a group is not a 20 mph solo time-trial goal; set the goal from solo training numbers on the bike you will race. Mistake three is ignoring the course profile. A hilly 40K needs a softer speed goal than a flat one, and a technical course with 20 corners needs softer still. Adjust the goal to the course, or the course adjusts it for you.

For informational purposes only, not medical advice. Consult a healthcare professional.

Hill-Adjusted Speed: The Climbing Penalty

Flat-land speed goals lie to you the moment the road tilts up. A rider who holds 18 mph on the flat might average 8 mph on a 6% grade at the same effort, and a century with 5,000 feet of climbing is a different event than a flat one. The honest way to set a goal on a hilly course: split it. Take the flat miles at your flat speed and the climbing miles at half that speed, then add them. Fifty flat miles at 18 mph is 2.78 hours; fifty rolling miles averaging 12 mph is 4.17 hours; total 6.95 hours, not the 5.5 the flat math promised.

Course profiles from the event organizer usually list total elevation gain. As a rough rule, every 1,000 feet of climbing adds about 10 to 12 minutes for a mid-pack rider versus the flat equivalent. A "flat" century at 18 mph takes 5.5 hours; the same distance with 4,000 feet of climbing takes closer to 6.5. Set the goal from the adjusted number and you will ride within yourself all day instead of blowing up at mile 60 wondering what went wrong.