Example 1
A steady 120 km/h for 2.5 h: classic road trip math.
Uniform Motion Distance Calculator
Enter speed and time. You get distance. Cruise control at 120 km/h for 2.5 h is 300 km. A 10 km/h run for 45 minutes (0.75 h) is 7.5 km.
Result
Speed and Time (h). Distance shows up here.
How it works
s = v·t is the simplest mechanics formula and the one you use for a commute, a late arrival, or bike range before dark. A steady 120 km/h for 2.5 h is s = 300 km. A train at 200 km/h for 1.5 h is 300 km on that stretch, before you add stops.
“Uniform” means constant speed. A real trip rarely is, so in practice you type an average. A high-speed train can do 200 km/h, but the city-to-city mean is lower because of slowdowns. The formula stays the same: average times time.
Time is in hours. A quarter hour is 0.25 h, 90 minutes is 1.5 h, 45 minutes is 0.75 h. A 10 km/h run for 0.75 h is 7.5 km. A bike at 20 km/h for half an hour is 10 km. A boat at 30 km/h for 8 h is 240 km. A flight at 850 km/h for 2 h is 1700 km.
If v is per hour, t must be in hours too, or the distance comes out on a strange scale. The metric/US switch changes the speed and distance pair. A 5 km/h walk for one hour is 5 km. A night run at 90 km/h for 9 h is 810 km.
The same formula turned around answers other questions. v = s/t lives on the average-speed page. t = s/v says 400 km at 100 km/h is 4 h. Thunder: sound ≈ 340 m/s, 6 s from flash to bang is about 2 km. Voyager coasts without a thruster because empty space has no drag: uniform motion needs no push.
A section-speed camera computes v = s/t between two gates. A last-second slowdown does not help. Here the unknown is s. When one of three is missing, open the v / s / t card.
Article with a problem: uniform motion. Average from s and t: v = s/t. Missing one of three: v / s / t calculator. When v changes: acceleration.
How to use
- Type speed in the labeled unit, preferably the average for the whole trip, for example 120 km/h.
- Type time in hours: 2.5 h of holiday driving, 0.75 h of running, 90 minutes = 1.5.
- Click Calculate. 120 km/h and 2.5 h give 300 km. 10 km/h and 0.75 h give 7.5 km.
- When you know s and t and want v, open average speed. The calculator multiplies.
- When v is changing and you want a, open acceleration. Here speed is steady or already averaged.
Formula
s = v · t
v is the constant (or average) speed and t is the travel time. If the speed is per hour, the time must be in hours too. Then the distance comes out in a consistent unit.
Letters in s = v·t
Distance at steady speed: s = v·t. Cruise control at 120 km/h for 2.5 h is 300 km; a 10 km/h run for 0.75 h is 7.5 km.
- s
- Distance in a unit that matches v and t. 120 × 2.5 = 300 km; a 200 km/h train for 1.5 h is also 300 km.
- v
- Steady or average speed, per hour when t is in hours. 10 km/h × 0.75 h = 7.5 km of running.
- t
- Travel time in hours. Type 45 minutes as 0.75, or 10 × 45 looks like 450 km.
Real-life examples
Example 2
A stretch covered at 177 km/h for 1.5 h.
Example 3
A brisk 5.00 km/h walk for one hour.
Example 4
An easy 18.0 km/h for 2 h along the levee.
Example 5
A crossing at 30.0 km/h for 8 h.
Example 6
Cruising at 850 km/h for 2 h.
Example 7
Running at 10.0 km/h for 45 minutes (0.75 h).
Example 8
A 20.0 km/h ride for half an hour.
Example 9
Averaging 11.0 km/h over 6 h of sailing.
Example 10
A night route averaging 90.0 km/h for 9 h.
Frequently asked questions
How much distance at 120 km/h and 2.5 h?
s = 300 km. At 200 km/h and 1.5 h also 300 km. At 90 km/h and 9 h it is 810 km.
How do I type time in minutes?
Divide by 60. 15 min is 0.25 h, 45 min is 0.75 h, 90 min is 1.5 h.
What if speed kept changing?
Type the average for the whole trip. s = v_avg · t by definition. Include stops when you want a door-to-door result.
How much at 10 km/h and 45 minutes?
0.75 h, s = 7.5 km. A bike at 20 km/h for 0.5 h is 10 km.
How far is a storm 6 s after the flash?
Sound ≈ 340 m/s, s ≈ 2.0 km. Rule of thumb: 3 s from flash to bang is about 1 km.
How does a section-speed camera work?
The cameras know s and t and compute v = s/t. Here you know v and t and compute s. Same relation, different unknown.
How far does light go in one second?
About 300,000 km. To the Moon, about 1.3 s. Still s = v·t, just with a huge v.
How do I compute time instead of distance?
t = s/v. 400 km at 100 km/h is 4 h. Check that v and t share a scale.
Can I work in miles?
Yes. The header switch changes the pair. Time stays in hours.
Where is average v = s/t?
On the average-speed page. The calculator multiplies v by t.
Knowledge sources
The formula is the school one. Units follow SI; NIST SP 330 and BIPM define the measures, not your result.
Page updated in 2026.