Whether you’re a drone operator, telecom engineer, hiker, or surveillance professional, determining line of sight (LOS) is crucial when evaluating visibility between two elevated points. Our Line of Sight Calculator is a fast, reliable, and easy-to-use online tool that helps you calculate the maximum distance two points can visually connect over the Earth’s curvature.
Line Of Sight Calculator
🚀 What Is a Line of Sight Calculator?
The Line of Sight Calculator estimates the maximum distance at which two objects or people, situated at different elevations, can see each other over the horizon. It takes into account the Earth’s curvature, providing accurate distance results based on the height of the observer and the target.
This is especially useful in:
- Drone and UAV flight planning
- Cell tower placement and radio communication
- Surveillance system planning
- Outdoor event coverage
- Maritime navigation
- Emergency services coordination
🛠️ How the Line of Sight Calculator Works
The tool uses a mathematical formula based on the Earth’s radius to calculate visibility distance:
Distance to horizon (in km) = √(2 × Earth radius × height above sea level)
(where Earth’s radius = 6371 km and height is in meters)
This calculation is done independently for both the observer and the target. The total line of sight is the sum of both horizon distances.
📋 Step-by-Step Guide: How to Use the LOS Calculator
Using our tool is incredibly simple:
1. Enter Observer Height
Input the height of the observer (e.g., a person, drone, or camera) in meters. For example, if a drone is flying at 120 meters, enter 120.
2. Enter Target Height
Input the height of the object you're observing or connecting with, also in meters. If it’s a tower that’s 80 meters tall, enter 80.
3. Click "Calculate"
Press the “Calculate” button. The tool instantly computes and displays the maximum line of sight distance in kilometers.
4. View Results
The result will show how far apart the two points can be to maintain clear visibility—assuming there are no obstacles in between like trees, buildings, or mountains.
5. Click "Reset" to Clear
To reset the form and enter new values, just click the “Reset” button.
🎯 Practical Example
Let’s walk through an example to demonstrate the tool’s value:
- Observer Height: 150 meters (drone altitude)
- Target Height: 100 meters (cell tower)
Calculation:
- √(2 × 6371 × 150 / 1000) ≈ 43.7 km (observer)
- √(2 × 6371 × 100 / 1000) ≈ 35.7 km (target)
Total Line of Sight = 43.7 + 35.7 = 79.4 km
This means the drone and the cell tower can maintain a direct line of sight up to 79.4 km, assuming no obstacles.
🧠 Why This Tool Matters
Understanding line of sight is essential for many fields:
- Telecommunications: Ensures stable connections between transmitters and receivers.
- Military and Security: Determines camera, radar, or watchtower coverage areas.
- Event Planning: Helps determine whether AV systems will have a clear range.
- Aviation and UAVs: Avoids loss of signal or control due to curvature blocking.
🧰 Tool Features & Benefits
- ✅ Simple two-field input system
- ✅ Instant and accurate calculations
- ✅ Responsive design (works on desktop and mobile)
- ✅ No installation or login required
- ✅ Educational for science and physics learning
📚 20 Frequently Asked Questions (FAQs)
1. What is the Earth’s radius used in this calculator?
The tool uses the standard Earth radius of 6371 km for calculations.
2. Can this tool be used for drone flight planning?
Yes, it’s ideal for drone pilots who need to maintain line-of-sight communication.
3. Is terrain taken into account?
No. The calculator assumes a perfect sphere and does not account for terrain, trees, or buildings.
4. What units should I use?
Enter heights in meters. The result will be displayed in kilometers.
5. Can I calculate LOS for a person standing on the ground?
Yes. Just enter the average human eye level, such as 1.6 meters.
6. How accurate is this calculator?
The calculation is mathematically accurate for ideal Earth curvature scenarios. It’s a strong estimate.
7. Can this help with satellite visibility?
For low-altitude satellites, it gives a rough estimate, but orbital mechanics are more complex.
8. Is it useful for security camera planning?
Yes. Helps determine how far cameras or observation posts can see.
9. Does atmospheric refraction affect results?
No. The basic version does not factor in light bending due to the atmosphere.
10. Is this tool free to use?
Absolutely! It's 100% free for personal and professional use.
11. Can I use this on mobile?
Yes, the tool is fully optimized for mobile devices.
12. Can the tool handle negative numbers?
No. Heights must be non-negative to ensure proper calculations.
13. Does it calculate between mountain tops?
Yes, just enter both mountain heights in meters.
14. What’s the maximum height allowed?
There’s no software limit, but practical visibility is usually under 300 km.
15. Can I save or export results?
You can copy the result manually, but there’s no export feature currently.
16. Can I factor in the observer’s elevation above sea level?
This tool assumes sea-level baseline. Add ground elevation to observer/target height.
17. Is this used in real-world engineering?
Yes, it’s a simplified model often used in early-stage planning for signal and visibility analysis.
18. How is total LOS distance computed?
By adding the observer and target distances to the horizon.
19. Can this be used for maritime purposes?
Yes. It helps determine if ships or coastal landmarks are visible to each other.
20. Are weather conditions considered?
No. The tool assumes clear visibility. Fog, rain, and haze aren’t factored in.
🏁 Final Thoughts
The Line of Sight Calculator is a powerful tool designed to offer quick, science-based answers to visibility-related questions. Whether you're in engineering, drone aviation, surveillance, or simply exploring physics, this tool simplifies complex calculations into a user-friendly experience.
✅ Try it today to enhance your planning and avoid visibility surprises.
✅ Bookmark the tool for future use, especially in fieldwork or technical studies.
Empower your decision-making with precision. Calculate your line of sight now!