Calculator Inputs
Example Data Table
| Start latitude | Start longitude | End latitude | End longitude | Time | Use case |
|---|---|---|---|---|---|
| 40.748817 | -73.985428 | 40.752726 | -73.977229 | 5 minutes | Short city movement |
| 51.500729 | -0.124625 | 51.503324 | -0.119543 | 8 minutes | Walking route check |
| 34.052235 | -118.243683 | 34.060000 | -118.250000 | 12 minutes | Vehicle log review |
Formula Used
Haversine distance:
a = sin²(Δφ / 2) + cos(φ1) × cos(φ2) × sin²(Δλ / 2)
c = 2 × atan2(√a, √(1 − a))
surface distance = earth radius × c
Optional elevation distance: distance = √(surface distance² + elevation change²)
Average speed: speed = distance ÷ elapsed time
Conversions: km/h = m/s × 3.6, mph = m/s × 2.2369362921, knots = m/s × 1.9438444924.
How to Use This Calculator
- Enter the start latitude and longitude in decimal degrees.
- Enter the end latitude and longitude in decimal degrees.
- Add start and end times, or leave them blank.
- When times are blank, enter a duration value and unit.
- Add elevation values when vertical movement matters.
- Choose the preferred speed unit and decimal places.
- Press the calculate button to show results above the form.
- Use CSV or PDF export for records and reports.
Understanding GPS Speed Calculation
GPS speed can be estimated from two recorded positions. Each position has latitude and longitude. Time separates the two records. The calculator measures the ground distance between both points. Then it divides that distance by elapsed time. This gives average speed for the interval.
Why Coordinates Need Special Math
Earth is not a flat sheet. Latitude and longitude sit on a curved surface. Simple straight line subtraction can create errors. The Haversine method handles this curve. It uses angular distance between two points. It then converts that angle into meters, kilometers, miles, or nautical miles.
What Makes This Calculator Useful
This page accepts decimal coordinates, time stamps, duration values, elevation, and unit choices. You can use it for walking logs, cycling checks, delivery routes, field surveys, and map testing. The result includes surface distance, optional three dimensional distance, average speed, pace, and heading. These details help compare motion from several views.
Good Data Gives Better Results
Small GPS errors can strongly affect short trips. A few meters of coordinate noise may look like high speed when the time gap is tiny. Use points with enough time between them. Check that latitude stays between minus ninety and ninety. Check that longitude stays between minus one hundred eighty and one hundred eighty.
When Elevation Matters
Most travel speed uses surface distance. Roads and tracks usually follow the ground. For climbing paths, drone logs, or steep surveys, elevation can improve the estimate. The calculator can combine surface distance with height change. It uses a right triangle idea. The three dimensional distance is slightly longer when height changes.
Using Results Safely
The answer is an average speed, not an instant speed. Real motion may include stops, turns, and acceleration. For safety or engineering decisions, compare several GPS samples. Remove bad points before reporting. Export the result to CSV or PDF when you need a record. Keep the original coordinates with the result. This makes later review easier. It also helps verify mapping assumptions.
For best practice, record points in the same datum. Many devices use WGS84. Avoid mixing copied map points with corrected survey points. That can shift distance. Always note the device, sample time, and route context for reference.
FAQs
1. What does this calculator measure?
It measures average speed between two GPS coordinate points. It uses distance and elapsed time. It also shows pace, bearing, and several speed units.
2. Which coordinate format should I enter?
Enter decimal degrees. For example, use 40.748817 instead of degrees, minutes, and seconds. South and west values should be negative.
3. Can I use start and end timestamps?
Yes. Enter both timestamps when available. The calculator will use their difference. If timestamps are empty, it uses the manual duration value.
4. Why is my speed too high?
Short time gaps can magnify GPS noise. A few meters of position error can produce a large speed. Use cleaner points and longer intervals.
5. What is the Haversine formula?
It is a spherical distance formula. It estimates distance between two latitude and longitude points on Earth’s curved surface.
6. Should I include elevation?
Include elevation for steep paths, climbing routes, drone logs, or survey work. Leave it off for normal road or walking averages.
7. Does this show instant speed?
No. It shows average speed over the selected interval. Instant speed needs frequent samples and extra filtering.
8. Can I export my result?
Yes. After calculation, use the CSV button for spreadsheet data. Use the PDF button for a simple printable report.