What is the formula for speed, distance and time?

Speed = distance ÷ time, distance = speed × time and time = distance ÷ speed. Every one of them keeps the units consistent: 325 miles ÷ 65 mph = 5 hours. The calculator converts everything to metres and seconds first, so you can mix units freely.

How do I find the time for a trip?

Divide the distance by the speed. 325 miles at 65 mph is 5 hours, shown as 5:00:00. If the speed and distance use different units, convert one first: 100 km at 60 mph is 100 ÷ (60 × 1.609344) hours. The calculator does this for you.

How do I find average speed from distance and time?

Divide the total distance by the total time. 60 miles in 1:30:00 is 40 mph, which is 64.37 km/h, 17.88 m/s or 34.76 knots. Choose “Speed” in “Solve for”, and enter the distance and the time.

How do I find how far I will go?

Multiply the speed by the time. At 55 mph for 2:30:00 you cover 137.5 miles (221.28 km). Choose “Distance” in “Solve for” and enter the speed and the time.

How are stops handled?

Stops are time with no distance covered. Solving for time adds them: 325 miles at 65 mph is 5:00:00 moving plus 0:45:00 stopped, 5:45:00 in all, an average of 56.52 mph. Solving for speed or distance, the time you enter is the total including stops, so the tool subtracts the stops to get the moving time first. The speed it reports is then the moving speed, with the average speed including stops beside it.

How is the arrival time worked out?

It is plain clock arithmetic: the departure time plus the total trip time. Leaving at 8:00 AM with a 5:00:00 trip arrives 1:00 PM; leaving at 21:00 for 10:00:00 arrives 7:00 AM (07:00), next day. It does not know about time zones or daylight saving, so if you cross a time zone, add or subtract the difference yourself, and a trip over a clock change can differ by an hour.

What is a knot, and how do I convert it?

A knot is one nautical mile per hour. A nautical mile is exactly 1,852 m, so 1 knot = 1,852 ÷ 3,600 = 0.5144 m/s = 1.852 km/h = 1.1508 mph. A passage of 480 nautical miles at 12 knots takes 1 day 16:00:00 (1 day 16 hours).

How do I convert mph to km/h and m/s?

Multiply mph by 1.609344 for km/h, because a mile is exactly 1.609344 km, and by 0.44704 for m/s (1,609.344 ÷ 3,600). The units table above shows all five speed units against each other. Walking 3 miles in an hour is 3 mph, 4.83 km/h.

Can I enter trips that last days?

Yes. Type a time with days (2d 3h 15m) or let the tool convert a long result: 3,000 nautical miles at 10 knots is 12 days 12:00:00, which is 12 days 12 hours. The limit is 10,000 days.

How are results rounded?

Only the shown results are rounded: speeds and distances to 2 decimals (4 decimals below 1), times to the nearest whole second. For example 1 mile at 1 km/h takes 1:36:34, since 1.609344 hours is 1 hour 36 minutes 33.6 seconds. The calculation itself keeps full precision.

Is anything I type sent anywhere?

No. The calculation runs in your browser and the values you enter are not sent or stored. The tool does arithmetic only: real journeys depend on traffic, weather, speed limits and route, so treat the result as an estimate for planning, not as navigation or safety advice.

Speed, Distance and Time Calculator

Speed = distance ÷ time, so any one of the three follows from the other two. 325 miles at 65 mph takes 5:00:00 (5 hours), and leaving at 8:00 AM you arrive at 1:00 PM. Choose what to solve for, enter the other two in mph, km/h, m/s, knots or ft/s and miles, kilometres, metres, feet or nautical miles, and read the answer in every unit. Add stops to get the total trip time and the average speed with stops, and a departure time to see the arrival time on the clock.

Updated 2026-10-16Runs in your browser: nothing you enter is uploadedHow this tool works

Time 5:00:00

325 mi at 65 mph takes 5 hours.

Time: 5:00:00
In words: 5 hours
Decimal hours: 5
Departure: 8:00 AM (08:00)
Arrival: 1:00 PM (13:00)

Speeds and distances are rounded to 2 decimals (4 below 1) and times to the nearest second; the arithmetic itself is not rounded. A mile is exactly 1.609344 km and a nautical mile exactly 1,852 m. Arrival times are clock arithmetic: no time zones or daylight saving.

Distance covered at common speeds

Miles travelled at a steady speed over common times. Each figure is the calculator’s own answer.
Speed	15 minutes	30 minutes	1 hour	2 hours	4 hours
30 mph	7.5 mi	15 mi	30 mi	60 mi	120 mi
40 mph	10 mi	20 mi	40 mi	80 mi	160 mi
50 mph	12.5 mi	25 mi	50 mi	100 mi	200 mi
60 mph	15 mi	30 mi	60 mi	120 mi	240 mi
70 mph	17.5 mi	35 mi	70 mi	140 mi	280 mi
80 mph	20 mi	40 mi	80 mi	160 mi	320 mi

Speed units compared

How many of the column unit make one of the row unit. Exact: 1 mile = 1,609.344 m, 1 nautical mile = 1,852 m, 1 foot = 0.3048 m.
1 of this	in mph	in km/h	in m/s	in knots	in ft/s
1 mph	1	1.6093	0.447	0.869	1.4667
1 km/h	0.6214	1	0.2778	0.54	0.9113
1 m/s	2.2369	3.6	1	1.9438	3.2808
1 knot	1.1508	1.852	0.5144	1	1.6878
1 ft/s	0.6818	1.0973	0.3048	0.5925	1

How to calculate speed, distance or time

Choose what to solve for. Pick time, speed or distance in “Solve for”. The two fields you need stay visible and the third is worked out.
Enter distance and speed (or the other pair). Type a number and pick its unit. For example 325 miles and 65 mph. Units can differ: 100 km at 60 mph is converted exactly first.
Type a time the easy way. Times accept 1:45:30, 45m, 1h 5m or 2d 3h 15m; a plain number is minutes. Use days for long trips.
Add stops if you will break the journey. Tick “With stops” and enter the minutes stopped. When you solve for time, the stops are added to the moving time; when you enter a time, it is the total including stops. 325 miles at 65 mph with 45 minutes of stops is 5:45:00.
Add a departure time to get the arrival. Set the departure time on the clock. The tool adds the total trip time and shows the arrival, with “next day” or “N days later” when it passes midnight: leaving at 21:00 for 10:00:00 arrives 7:00 AM (07:00), next day.

Frequently asked questions

What is the formula for speed, distance and time?: Speed = distance ÷ time, distance = speed × time and time = distance ÷ speed. Every one of them keeps the units consistent: 325 miles ÷ 65 mph = 5 hours. The calculator converts everything to metres and seconds first, so you can mix units freely.
How do I find the time for a trip?: Divide the distance by the speed. 325 miles at 65 mph is 5 hours, shown as 5:00:00. If the speed and distance use different units, convert one first: 100 km at 60 mph is 100 ÷ (60 × 1.609344) hours. The calculator does this for you.
How do I find average speed from distance and time?: Divide the total distance by the total time. 60 miles in 1:30:00 is 40 mph, which is 64.37 km/h, 17.88 m/s or 34.76 knots. Choose “Speed” in “Solve for”, and enter the distance and the time.
How do I find how far I will go?: Multiply the speed by the time. At 55 mph for 2:30:00 you cover 137.5 miles (221.28 km). Choose “Distance” in “Solve for” and enter the speed and the time.
How are stops handled?: Stops are time with no distance covered. Solving for time adds them: 325 miles at 65 mph is 5:00:00 moving plus 0:45:00 stopped, 5:45:00 in all, an average of 56.52 mph. Solving for speed or distance, the time you enter is the total including stops, so the tool subtracts the stops to get the moving time first. The speed it reports is then the moving speed, with the average speed including stops beside it.
How is the arrival time worked out?: It is plain clock arithmetic: the departure time plus the total trip time. Leaving at 8:00 AM with a 5:00:00 trip arrives 1:00 PM; leaving at 21:00 for 10:00:00 arrives 7:00 AM (07:00), next day. It does not know about time zones or daylight saving, so if you cross a time zone, add or subtract the difference yourself, and a trip over a clock change can differ by an hour.
What is a knot, and how do I convert it?: A knot is one nautical mile per hour. A nautical mile is exactly 1,852 m, so 1 knot = 1,852 ÷ 3,600 = 0.5144 m/s = 1.852 km/h = 1.1508 mph. A passage of 480 nautical miles at 12 knots takes 1 day 16:00:00 (1 day 16 hours).
How do I convert mph to km/h and m/s?: Multiply mph by 1.609344 for km/h, because a mile is exactly 1.609344 km, and by 0.44704 for m/s (1,609.344 ÷ 3,600). The units table above shows all five speed units against each other. Walking 3 miles in an hour is 3 mph, 4.83 km/h.
Can I enter trips that last days?: Yes. Type a time with days (2d 3h 15m) or let the tool convert a long result: 3,000 nautical miles at 10 knots is 12 days 12:00:00, which is 12 days 12 hours. The limit is 10,000 days.
How are results rounded?: Only the shown results are rounded: speeds and distances to 2 decimals (4 decimals below 1), times to the nearest whole second. For example 1 mile at 1 km/h takes 1:36:34, since 1.609344 hours is 1 hour 36 minutes 33.6 seconds. The calculation itself keeps full precision.
Is anything I type sent anywhere?: No. The calculation runs in your browser and the values you enter are not sent or stored. The tool does arithmetic only: real journeys depend on traffic, weather, speed limits and route, so treat the result as an estimate for planning, not as navigation or safety advice.

How it works

Everything is computed in metres, seconds and metres per second. A distance unit is multiplied by its exact length in metres (1 mile = 1,609.344 m, 1 kilometre = 1,000 m, 1 foot = 0.3048 m, 1 nautical mile = 1,852 m; the same constants the unit converter uses), and a speed unit by its exact speed in metres per second (1 mph = 1,609.344 ÷ 3,600, 1 km/h = 1,000 ÷ 3,600, 1 knot = 1,852 ÷ 3,600, 1 ft/s = 0.3048). The three solves are: time = distance ÷ speed, speed = distance ÷ time, distance = speed × time. With stops, the total time is the moving time plus the time stopped: solving for time adds the stops to the moving time, and solving for speed or distance subtracts them from the entered total to get the moving time, so the speed is distance ÷ moving time. The average speed with stops is distance ÷ total time. Times are read like the pace calculator’s (1:45:30, 45m, 1h 5m; a plain number is minutes) with days added (2d 3h), and are shown as h:mm:ss with whole days when over 24 hours, rounded to the nearest second. The arrival is the departure time of day plus the total time, whole seconds, wrapped around midnight with the number of days later; it ignores time zones and daylight saving. Speeds and distances are shown to 2 decimals (4 below 1) with trailing zeros dropped. Limits: distances up to 10⁹ km, speeds up to 10⁹ m/s and trips up to 10,000 days. Everything runs in your browser.

Sources

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