Accurate speed tools for pilots, sailors, and racers. Choose wind mode, batch lists, and rounding. See time, distance, and conversions in one place today.
| Scenario | Input | Key output |
|---|---|---|
| Simple conversion | 120 kn | 222.24 km/h |
| Wind‑adjusted flight | TAS 110 kn, Track 090°, Wind 20 kn from 240° | Estimated GS ≈ 106.54 kn |
| Time from speed | Distance 45 NM, Speed 18 kn | Time ≈ 2:30 |
Unit conversions:
Wind‑adjusted ground speed:
Time and distance:
Knots are speed in nautical miles per hour, which aligns with charts, waypoints, and marine navigation. When you keep speed in knots, distance in nautical miles, and time in hours, the math stays direct. For example, 24 NM at 12 kn takes 2 hours. This consistency helps reduce mistakes during quick route checks.
Many dashboards and regulations display km/h or mph. This calculator uses standard factors: 1 kn = 1.852 km/h and 1 kn = 1.150779448 mph. It also provides m/s and ft/s for engineering logs, plus per‑minute units for short interval timing.
Ground speed changes when wind adds or subtracts along your track. The tool resolves wind into headwind or tailwind and crosswind components using the angle between “wind from” and track. Then it estimates ground speed and wind correction angle for a steady wind and constant airspeed. It is helpful when a forecast headwind or tailwind changes arrival timing by minutes, even on short legs too.
Crosswind is signed: positive means wind from the right, negative from the left. The correction angle uses asin(XW/TAS), so it grows as crosswind increases and shrinks as airspeed rises. If crosswind exceeds airspeed, the calculator warns that an exact correction is not possible for that input set.
Use the Time/Distance mode in two directions. Enter speed and distance to get travel time, or enter distance and time to find the required speed in knots. Distances can be entered as NM, km, miles, meters, or feet, then normalized internally to nautical miles for consistent results. If you enter 30 km, the calculator converts it to about 16.20 NM before computing time and speed accurately here.
When you have many speeds to compare, paste a list separated by spaces, commas, semicolons, or new lines. The output table shows mph, km/h, m/s, and ft/s for each row, which is useful for performance notes, route options, or classroom exercises.
After calculating, download CSV for spreadsheets or PDF for a clean snapshot. Exports include your inputs, key components, and final ground speed values. Choose fixed decimals for consistent reporting, or significant figures when comparing measurements with different sensor precision. Keep the CSV for spreadsheets, and use the PDF for a shareable snapshot during briefings later.
Q1: What is the difference between knots and ground speed?
Knots are a unit of speed. Ground speed is the actual speed over the ground, which may differ from airspeed due to wind, current, or drift.
Q2: Why does wind direction use “wind from”?
Aviation and marine reports usually state the direction the wind is coming from. The calculator converts that direction relative to your track to find headwind and crosswind components.
Q3: Can I use this for boats and aircraft?
Yes. The unit conversions are universal. The wind‑adjusted mode matches a simple wind triangle approach, suitable for estimates when wind is steady and speed is constant.
Q4: What if I only know km/h, not knots?
Convert first: knots = km/h ÷ 1.852. Enter the converted value, then read all other units and optional wind or time outputs.
Q5: Why does the tool warn about crosswind exceeding airspeed?
If crosswind is larger than airspeed, the required correction angle would exceed physical limits for steady tracking. The calculator still shows components so you can review the input realism.
Q6: Which rounding option should I choose?
Use fixed decimals for logs, invoices, or reports. Use significant figures for measurements taken from instruments, where precision varies and comparisons should respect sensor uncertainty.
Important Note: All the Calculators listed in this site are for educational purpose only and we do not guarentee the accuracy of results. Please do consult with other sources as well.