Overview
Convert between kilometres per hour, miles per hour, metres per second and knots.
Objective
Use the correct measurements, units and method to produce an accurate, clearly labelled result.
What You Need
- A speed value
- Starting and target speed units
- Conversion factor
- Calculator if needed
Before You Start
Write down the value or dimensions you have, including their units. Decide exactly what unit or result you need before calculating. Keeping the units visible makes errors much easier to spot.
How to Do It
- Identify both speed units.
- Choose the correct conversion factor.
- Multiply or divide as required.
- Round appropriately.
- Write the full target unit.
Worked Example
Convert 72 km/h to m/s. Divide by 3.6: 72 ÷ 3.6 = 20 m/s.
Useful Tips
- Use 3.6 between m/s and km/h.
- Keep distance and time units together.
- Estimate the answer before calculating.
Common Mistakes
- Converting only the distance part of the unit.
- Multiplying by 3.6 in the wrong direction.
- Confusing knots with kilometres per hour.
Important Notes
Conversion factors and measurement standards can vary by country or context. When accuracy matters, confirm the standard being used and keep enough decimal places until the final answer.
FAQ
When should I round the answer?
Keep the full value during the calculation and round at the end to a level of precision suitable for the task.
Why should I always write the units?
The unit tells you what the number represents and helps reveal mistakes when converting or calculating.