Calculator Form
Formula Used
The calculator uses the haversine formula. It estimates the great circle distance between two latitude and longitude points.
a = sin²(Δφ / 2) + cos(φ1) × cos(φ2) × sin²(Δλ / 2)
c = 2 × atan2(√a, √(1 − a))
distance = Earth radius × c
adjusted limit = radius limit − safety buffer
remaining distance = adjusted limit − air distance
surface cap area = 2 × π × R² × (1 − cos(radius / R))
How To Use This Calculator
- Enter the origin name and destination name.
- Add latitude and longitude for both points.
- Keep the radius at 100 miles, or enter another limit.
- Add a safety buffer when conservative planning is needed.
- Select the Earth radius model and decimal precision.
- Press the calculate button.
- Review the result above the form.
- Use the CSV or PDF button to save the report.
Example Data Table
| Origin Latitude | Origin Longitude | Destination Latitude | Destination Longitude | Radius | Expected Use |
|---|---|---|---|---|---|
| 40.7128 | -74.0060 | 41.2033 | -77.1945 | 100 | Check if a field site is inside the base radius. |
| 34.0522 | -118.2437 | 34.4208 | -119.6982 | 100 | Compare a coastal destination against a local radius. |
| 41.8781 | -87.6298 | 42.2711 | -89.0940 | 100 | Review a dispatch coverage point. |
About the 100 Air Mile Radius Calculator
A 100 air mile radius is a straight line distance from one base point. It is not a road route. This calculator uses latitude and longitude to test whether a destination sits inside a chosen air mile circle. It also returns bearing, central angle, buffer allowance, travel time, and equivalent units.
Why Straight Line Distance Matters
Physics treats the Earth as a curved body. Two points on that surface form an arc, not a flat map line. For short ranges, the difference is small, yet coordinates still give a cleaner result than visual map guessing. A radius test helps drivers, pilots, field teams, surveyors, and dispatchers check coverage before planning a trip.
What The Results Mean
The main result shows the air distance in statute miles. It compares that value with the adjusted limit after any safety buffer. If the remaining distance is positive, the point is inside the radius. If it is negative, the point is outside by that many miles. The bearing shows the starting direction from the base to the destination. The central angle shows the angular separation on Earth.
Practical Planning Notes
Use accurate coordinates whenever possible. Small coordinate errors can move a point by many yards. Choose a larger buffer when addresses are approximate, when rounding matters, or when records must stay conservative. The travel time field is only an estimate. It uses the selected average speed and the straight line distance. Real travel can be longer because roads, airspace, terrain, and detours change the path.
Coordinate Entry Tips
Latitude north is positive, and south is negative. Longitude east is positive, and west is negative. Enter decimals for best accuracy. When you only have degrees and minutes, convert them first. Avoid rounded city center coordinates when the destination is a precise site. Check values before exporting reports.
Better Field Decisions
This tool is useful when a simple 100 mile road search is not enough. It separates radius eligibility from route planning. First check the air mile limit. Then confirm the practical route with local rules and real maps. Keep exported reports with job notes, audit files, or dispatch records. Use it often, and refine your field decisions safely.
FAQs
What is a 100 air mile radius?
It is a straight line circle measured 100 miles from a base point. It does not follow roads, paths, or driving routes.
Does this calculator measure road distance?
No. It measures air distance between coordinates. Road distance can be longer because roads curve, detour, and avoid obstacles.
Which formula does the calculator use?
It uses the haversine formula. This formula estimates the great circle distance between two points on the Earth.
Why do I need latitude and longitude?
Coordinates give precise positions. They help the calculator measure the curved surface distance more accurately than city names or rough addresses.
What does the safety buffer do?
The buffer subtracts miles from the selected radius. It helps create a conservative limit when coordinates or records may be rounded.
What is the bearing result?
Bearing is the starting direction from the origin to the destination. It is shown in degrees from north.
Can I use a radius other than 100 miles?
Yes. The form accepts any positive radius. Keep 100 miles for standard 100 air mile checks.
Why are spherical and flat areas different?
The spherical area follows Earth curvature. The flat area uses a simple circle estimate. For small radii, the values are usually close.