Speed Distance Time Calculator
Calculate speed, distance or time — enter any two values, get the third. Instant, free, no sign-up.
At 60 mph for 120 miles, it takes 2 hours. Enter any two values below to work out speed, distance or time in your own units.
Speed Distance Time Calculator
Pick what you want to find, enter any two values, and the third is calculated instantly. Units are converted automatically — mix miles with km/h freely.
Speed Converter
Convert any speed to km/h, mph, m/s and knots instantly.
Enter a speed value.
The Speed, Distance and Time Formula
Speed = Distance ÷ Time
v = d ÷ t
e.g. 120 miles ÷ 2 hours = 60 mph
Distance = Speed × Time
d = v × t
e.g. 60 mph × 2 hours = 120 miles
Time = Distance ÷ Speed
t = d ÷ v
e.g. 500 miles ÷ 50 mph = 10 hours
Speed is also called rate — rate = distance ÷ time (r = d/t). The three formulas are the same relationship rearranged, so distance is speed times time and time is distance divided by speed. A km/h speed comes from kilometers divided by hours — the unit itself tells you the formula.
The Speed Distance Time Triangle
- Cover D → S × T = Distance
- Cover S → D ÷ T = Speed
- Cover T → D ÷ S = Time
SI Units Used Here
| Quantity | Symbol | SI unit |
|---|---|---|
| Speed / Velocity | v | metres per second (m/s) |
| Distance | s | metres (m) |
| Time | t | second (s) |
Why 1 m/s = 3.6 km/h
1 km/h = 1000 m ÷ 3600 s = 1/3.6 m/s ≈ 0.27778 m/s (which is the same as ×5/18). So to convert m/s to km/h, multiply by 3.6: 10 m/s = 36 km/h. To convert km/h to m/s, divide by 3.6: 72 km/h = 20 m/s.
Speed & Distance Unit Converter
Conversion factors are exact values, shown rounded to 6 decimal places.
| Unit | m/s | km/h | mph | knot |
|---|---|---|---|---|
| 1 m/s | 3.6 | 2.236936 | 1.943844 | |
| 1 km/h | 0.277778 | 0.621371 | 0.539957 | |
| 1 mph | 0.44704 | 1.609344 | 0.868976 | |
| 1 knot | 0.514444 | 1.852 | 1.150779 |
Distance conversions
| Unit | km | m | nautical miles |
|---|---|---|---|
| 1 mile | 1.609344 | 1609.344 | 0.868976 |
| 1 nm | 1.852 | 1852 | 1.150779 |
60 mph is the same as 96.56 km/h — about 27 m/s.
100 km/h is about 62 mph.
A knot equals one nautical mile per hour, about 1.852 km/h or 1.151 mph.
How Fast Is That? Speed Reference Table
Compare everyday speeds against some of the fastest things on Earth.
| Speed | m/s | km/h | mph |
|---|---|---|---|
| Average walking speed | 1.4 | 5 | 3.1 |
| Fastest human sprint (Usain Bolt) | 12.42 | 44.7 | 27.8 |
| Cheetah top speedTop recorded range 93–104 km/h | 28.9 | 104 | 64.6 |
| Car highway cruising (typical)Typical highway cruising speed | 30.6 | 110 | 68.4 |
| Jet airliner cruise (typical)Typical cruise (Mach 0.78–0.855) | 250 | 900 | 559.2 |
| Earth orbital speed | 29,783 | 107,218 | 66,623 |
| Speed of light (vacuum) | 299,792,458 | 1,079,252,849 | 670,616,629 |
Facts verified against Wikipedia (2026-08-24): Usain Bolt's 9.58 s 100 m peak is 12.42 m/s; Earth's average orbital speed is 29.7827 km/s. Cheetah row shows the top of the recorded 93–104 km/h range. Car and airliner rows are typical values.
For distance sense: 20 miles is about 32 km — roughly half an hour of driving.
How to Calculate Speed, Distance and Time
1. Pick what you want to find
Speed, Distance or Time — the mode buttons decide which value is the result.
2. Enter any two values
Type the values and pick their units. Mixing miles with km/h is fine — conversion is automatic.
3. Read the result
The third value appears instantly — time as HH:MM:SS, speed in all four common units.
Worked example: how long is 60 miles at 40 km/h?
- Convert the distance to the same unit system: 60 miles = 60 × 1.609344 = 96.56064 km.
- Find the hours: 96.56064 ÷ 40 = 2.414016 hours, which is 2 full hours.
- Find the minutes: 0.414016 × 60 = 24.84096 minutes, which is 24 full minutes.
- Find the seconds: 0.84096 × 60 = 50.4576 seconds, rounded to 50 seconds.
- Combine: 02:24:50 (2 hours 24 minutes 50 seconds).
The same steps work for any units — the calculator does them instantly in the background.
Reading a Distance-Time Graph
On a distance-time graph, time runs along the x-axis and distance along the y-axis. The slope (steepness) of the line is the speed — a steeper line means a faster object; a horizontal line means the object is stationary. A straight line at 60 mph shows constant speed: in every hour the line rises by 60 miles, so the slope is 60.
How to calculate the average speed of a car
- Measure the actual distance driven, for example with a map app (Google Maps route distance).
- Record the total driving time — subtract rest and stops; average speed is driving speed, not wall-clock time including parking.
- Apply the formula: speed = distance ÷ time.
- Example: 120 miles with a 15-minute rest break, actual driving 2 hours → 120 ÷ 2 = 60 mph.
Common Misconceptions
Average speed is not the mean of the speeds
Driving out at 60 km/h and back at 40 km/h over the same distance gives an average of 48 km/h, not 50. The correct formula is total distance ÷ total time: 2 ÷ (1/60 + 1/40) = 48 km/h — you spend longer at the slower speed.
Speed vs. velocity
Speed is distance ÷ time (a scalar — just a number). Velocity includes direction (a vector). Your car's speedometer shows speed; a GPS route planner works with velocity.
Common Uses
Road trips & driving
Estimate how long a drive takes at highway speed, or what speed you need to arrive on time. Add the result to a Time From Now Calculator to get the exact arrival time.
School & homework
Physics and math problems: v = d/t with mixed units (miles + km/h), unit conversions and the speed-distance-time triangle.
Running & cycling
Work out pace from distance and time — 25 miles in 15 minutes is 100 mph; a 10 km run in 50 minutes is 12 km/h.
Aviation & marine
Knots and nautical miles for pilots and sailors: 15 knots for 20 minutes covers 5 nautical miles (the 60-D street rule: speed × minutes ÷ 60 = distance).
Need the duration between two clock times instead? Use the Time Duration Calculator. Converting a time like 02:24:50 to decimal hours? See the Time to Decimal Calculator.
Frequently Asked Questions
How do I calculate travel time?
Travel time = distance ÷ speed. Drive 120 miles at 60 mph, and it takes 120 ÷ 60 = 2 hours. Enter the distance and speed in the calculator above and the time is shown as HH:MM:SS plus total hours, minutes and seconds.
How do you calculate speed?
Speed = distance ÷ time. For example, 100 km in 1 hour 15 minutes is 100 ÷ 1.25 = 80 km/h. The calculator shows the result in km/h, mph, m/s and knots at the same time.
What is the formula for distance?
Distance = speed × time. At 60 mph for 2 hours you travel 60 × 2 = 120 miles. Units are converted automatically, so you can mix miles with km/h and still get the right answer.
How fast is 25 miles in 15 minutes in mph?
25 miles in 15 minutes is 100 mph. Fifteen minutes is a quarter of an hour, so speed = 25 ÷ 0.25 = 100 mph.
What is the speed distance time triangle?
The speed distance time triangle is a visual memory aid. Speed sits above Distance and Time, with the division line between them. Cover the value you want: cover Speed to see Distance ÷ Time, cover Distance to see Speed × Time, cover Time to see Distance ÷ Speed.
What is the average speed formula?
Average speed = total distance ÷ total time. Driving out at 60 km/h and returning at 40 km/h over equal distances gives 2 ÷ (1/60 + 1/40) = 48 km/h — not 50 km/h, because you spend more time at the slower speed.
How do I convert mph to km/h?
Multiply mph by 1.609344. So 60 mph = 60 × 1.609344 = 96.56 km/h, which is about 27 m/s. Use the Speed Converter above for any value.
How many mph is 100 km/h?
100 km/h is about 62 mph. Exactly, 100 ÷ 1.609344 = 62.14 mph. A useful rule of thumb: divide km/h by 1.6, or multiply mph by 1.6.
What is a knot in mph?
A knot is one nautical mile per hour, equal to 1.852 km/h or about 1.151 mph. Knots are used for air and sea travel.
How do you calculate speed from a distance-time graph?
On a distance-time graph, time runs along the x-axis and distance along the y-axis. The slope (steepness) of the line is the speed: a steeper line means a faster object, and a horizontal line means the object is stationary.
What is the difference between speed and velocity?
Speed is how fast an object moves (distance ÷ time, a scalar). Velocity is speed in a given direction (a vector). A car driving 60 mph around a circular track has constant speed but constantly changing velocity.
How long does it take to drive 120 miles at 60 mph?
It takes 2 hours. Time = distance ÷ speed = 120 ÷ 60 = 2 hours. Enter 120 miles and 60 mph in the calculator to see it as 02:00:00.
How far can you travel at 60 mph in 2 hours?
You travel 120 miles. Distance = speed × time = 60 × 2 = 120 miles, or about 193.12 km.
What does "rate" mean in the distance rate time formula?
In the distance-rate-time formula, rate is another word for speed: rate = distance ÷ time (r = d/t). The three formulas are simply rearrangements: d = r × t, r = d ÷ t and t = d ÷ r.
How do I convert miles to kilometers?
Multiply miles by 1.609344. So 5 miles = 8.05 km (about 8 km), and a marathon distance of 26.2 miles = 42.16 km. One nautical mile is 1.852 km.
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Accuracy & Disclaimer
All calculations run locally in your browser — nothing is sent to a server. Conversion factors use the international yard-and-pound agreement values (1 mile = 1.609344 km, 1 mph = 0.44704 m/s, 1 knot = 1.852 km/h). Reference-table facts were verified against Wikipedia on 2026-08-24. While every effort is made for accuracy, results are for planning and education — always confirm critical journey and navigation data from official sources.