Speed Calculator
Calculate speed, distance, or time — and convert between MPH, KPH, and m/s.
Speed Calculator
Calculate speed, distance, or time — and convert between MPH, KPH, and m/s.
Unit Conversion
ℹ️ All units normalised to a common base before converting to ensure accuracy
Disclaimer
Results provided by this calculator are for informational and educational purposes only. They are based on the values you enter and standard formulas, and should not be considered financial, medical, legal, or professional advice. Always consult a qualified professional before making important decisions based on these results. Roughtools makes no warranties regarding the accuracy or completeness of these calculations for your specific situation.
Frequently Asked Questions
Pro Tips
Always double-check your unit conversion direction — dividing when you should multiply (or vice versa) produces a result off by the conversion factor squared.
For temperature conversions, remember the formulas differ: Celsius to Fahrenheit = (C × 9/5) + 32. Fahrenheit to Celsius = (F − 32) × 5/9. Kelvin = Celsius + 273.15.
Imperial units have multiple definitions (fluid ounce vs weight ounce, US vs UK gallon). Always confirm which system applies — especially for cooking or scientific work.
Significant figures matter in scientific conversions. If your input has 2 significant figures, don't report 6 decimal places of precision — it implies false accuracy.
When to Use This Calculator
Convert between metric and imperial units for temperature, distances, weights, and speeds when travelling abroad.
Convert between US and metric measurements for international recipes or ingredient scaling.
Convert units for scientific calculations where SI units are required.
Convert between measurement systems when working with international suppliers or standards.
Convert units to compare product sizes and prices across different packaging formats.
About the Speed Calculator
This speed calculator solves for speed, distance, or time when you provide the other two, and converts between miles per hour (mph), kilometers per hour (km/h), meters per second (m/s), feet per second (ft/s), knots, and Mach number. Use it to find your average speed from a trip distance and time, calculate travel time, or convert a speed between unit systems. Built for drivers, pilots, athletes, sailors, and physics students.
How to Use the Speed Calculator
- 1
Select whether you want to calculate speed, distance, or time.
- 2
Enter the two known values with their units.
- 3
See the calculated third value plus unit conversions for speed in all systems.
- 4
For a pure unit conversion, enter a speed value and see it in mph, km/h, m/s, knots, and Mach.
- 5
Use for trip planning, race pacing, physics homework, or aviation/marine navigation.
Related Calculators
View all →Pace Calculator
Calculate running pace, finish time, or distance for any race or training run.
Conversion Calculator
Convert between common units of length, weight, volume, temperature, and more.
Fuel Cost Calculator
Calculate trip fuel cost based on distance, fuel economy, and local gas prices.
Gas Mileage Calculator
Calculate your car's MPG, litres per 100 km, and total fuel cost per trip.
Distance Calculator
Calculate distance between two points using coordinates or the distance formula.
Your input is processed locally in your browser and is never stored, transmitted, or shared with any server. See our Privacy Policy.