Speed Distance Time Calculator -- Solve for Any Variable

Speed Distance Time Calculator

Select what to solve for, enter the two known values, and get instant results with conversions across multiple units.

The Speed Distance Time Formula

The relationship between speed, distance, and time is one of the most fundamental formulas in physics. All three formulas are rearrangements of the same equation:

To use the triangle: cover the variable you want to solve for. If the remaining two are side by side, multiply them. If one is above the other, divide the top by the bottom.

Common Speeds Reference

For context, here are typical speeds for various activities and objects:

Real-World Examples

How to Use This Calculator

1. Choose what to solve for -- select Speed, Distance, or Time using the toggle buttons at the top. The selected variable becomes the output.
2. Enter the two known values -- fill in the remaining two fields with your known values and select the appropriate units.
3. Read your result -- the calculator solves instantly and shows the answer in your chosen unit along with conversions to all other supported units.

Use the quick example buttons to see pre-filled scenarios for common use cases like marathon pacing, road trips, and flights.

Frequently Asked Questions

How do I calculate speed from distance and time?

Divide the distance by the time: Speed = Distance / Time. Make sure your units are consistent. For example, if you travel 100 miles in 2 hours, your speed is 100 / 2 = 50 mph. If you mix units (e.g., kilometers and hours), the result will be in the corresponding unit (km/h).

How do I calculate distance from speed and time?

Multiply speed by time: Distance = Speed x Time. For example, traveling at 60 mph for 3 hours covers 60 x 3 = 180 miles. If your time is in minutes, convert to hours first (divide by 60) when using mph or km/h.

How do I calculate time from speed and distance?

Divide the distance by the speed: Time = Distance / Speed. For example, 150 miles at 50 mph takes 150 / 50 = 3 hours. The calculator handles the conversion to hours, minutes, and seconds automatically.

How do I convert between mph and km/h?

Multiply mph by 1.60934 to get km/h. Multiply km/h by 0.621371 to get mph. For a quick estimate, mph x 1.6 is roughly km/h, and km/h x 0.6 is roughly mph.

What is a knot?

A knot is one nautical mile per hour. One nautical mile is 1,852 meters (about 1.15 statute miles). Knots are the standard speed unit in aviation and maritime navigation. 1 knot = 1.852 km/h = 1.15078 mph.

Can I enter time in minutes and seconds?

Yes. The time input has separate fields for hours, minutes, and seconds. You can enter any combination. For example, 1 hour 30 minutes 45 seconds would be entered as 1h, 30m, 45s.

What is average speed vs. instantaneous speed?

Average speed is the total distance divided by the total time for a journey. Instantaneous speed is the speed at a specific moment (what your speedometer shows). This calculator computes average speed, which assumes constant velocity over the given time period.

Does this calculator store my data?

No. All calculations run entirely in your browser. No data is sent to any server, and nothing is stored.

Privacy & Limitations

Privacy: This calculator runs entirely in your browser. No data is transmitted or stored anywhere.

Limitations: This calculator assumes constant speed (average speed). It does not account for acceleration, deceleration, stops, or varying terrain. For trip planning, actual travel times may differ due to traffic, weather, and road conditions.

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Speed Distance Time Calculator FAQ