What is the formula linking speed, distance and time?

The basic relationship is speed = distance ÷ time. Using symbols, v = d / t, d = v × t and t = d ÷ v. The calculator lets you solve for any of the three variables from the other two.

Which units does this speed, distance, time calculator support?

You can work with metres, kilometres, miles and nautical miles for distance; seconds, minutes and hours for time; and m/s, km/h, mph and knots for speed. The tool converts everything internally so you can mix units safely.

What is the difference between speed and average speed?

Instantaneous speed is the speed at a specific moment. Average speed over a trip is defined as total distance travelled divided by total time taken. The calculator includes a dedicated average speed section for multi-leg journeys.

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

To convert from km/h to m/s, divide by 3.6. To convert from m/s to km/h, multiply by 3.6. For example, 90 km/h ≈ 25 m/s and 10 m/s = 36 km/h. The result table in the calculator shows these conversions automatically.

Can I mix units, for example miles and hours or metres and minutes?

Yes. The calculator converts all values to SI units internally (metres and seconds) and then outputs your requested unit set. You can safely combine miles with minutes, kilometres with hours, or metres with seconds.

Speed, Distance, Time Calculator

Use this calculator to solve for speed, distance or time from the basic relationship \(v = d / t\). Mix units freely: kilometres, miles, metres, nautical miles, seconds, minutes or hours.

The tool also computes equivalent speeds in m/s, km/h, mph and knots, and includes an average speed calculator for multi-leg trips.

Solve for speed, distance or time

What do you want to calculate?

Distance (d)

Examples: 5 km, 2000 m, 3 miles, 2.5 nautical miles.

Time (t)

Examples: 2 h, 45 min, 30 s. You can use decimals (e.g. 1.5 h).

Preferred speed unit for the main result

The result table will show all units; this setting controls the highlighted one.

Use dot or comma as decimal separator. Empty fields are treated as unknowns.

Result

Equivalent speeds

Unit	Value

Average speed for multi-leg trips

Average speed over a whole journey is defined as \( \text{average speed} = \dfrac{\text{total distance}}{\text{total time}} \), not the simple average of segment speeds. Use this section to combine several legs.

Trip legs

Leg	Distance	Unit	Time	Unit

Tip: you can mix units across legs (e.g. some in km, some in miles). The calculator converts everything internally and reports the global average speed.

Speed–distance–time relationship

The core relationship between speed, distance and time is

\( v = \dfrac{d}{t}, \quad d = v \cdot t, \quad t = \dfrac{d}{v} \)

where \(v\) is speed, \(d\) is distance, and \(t\) is time.

As long as you know any two of the three quantities, you can compute the third. The only strict requirement is to keep units consistent – for example, kilometres with hours or metres with seconds.

Speed–distance–time triangle

A popular memory aid is the speed–distance–time triangle. Draw a triangle, put distance \(d\) at the top, and speed \(v\) and time \(t\) at the bottom corners:

d
v t

Cover the quantity you want: if you cover \(v\), the remaining layout shows \(d / t\); cover \(d\), you see \(v \cdot t\); cover \(t\), you see \(d / v\).

Worked examples

Example 1 – Find speed

A car travels 150 km in 2 hours. What is its average speed?

\( v = \dfrac{d}{t} = \dfrac{150 \text{ km}}{2 \text{ h}} = 75 \text{ km/h}. \)

Example 2 – Find distance

A runner maintains a speed of 12 km/h for 30 minutes. How far do they run?

Convert 30 minutes to hours: \( 30 \text{ min} = 0.5 \text{ h} \). \( d = v \cdot t = 12 \text{ km/h} \times 0.5 \text{ h} = 6 \text{ km}. \)

Example 3 – Find time

A cyclist travels at 20 km/h and needs to cover 35 km. How long will it take?

\( t = \dfrac{d}{v} = \dfrac{35 \text{ km}}{20 \text{ km/h}} = 1.75 \text{ h} \approx 1 \text{ h } 45 \text{ min}. \)