Use this calculator to check the approximate radar horizon in kilometres from the heights you enter.
Inputs
This topic also has a deeper guide and a printable reference pack, so you can move from the live answer into the method, assumptions, and worked examples without leaving the topic cluster.
These are the main values the calculator uses. Keep the units consistent and, where relevant, match the assumptions explained in the related guide.
Unit: m
Enter the value using the unit shown on the field.
Unit: m
Enter the value using the unit shown on the field.
Use this page for quick line-of-sight horizon checks when antenna height and target height are the main factors you need to compare.
The main result is the estimated radar horizon in kilometres. The supporting value repeats the antenna height so the physical basis of the estimate stays visible.
Raising either the antenna or the target increases the horizon because the estimate depends on the square root of each height.
This is a standard approximation that assumes typical atmospheric refraction. Terrain, clutter, ducting, and system performance can all limit real detection range.
No. It is a geometric visibility estimate. Real detection also depends on target size, radar performance, clutter, and propagation conditions.
Estimate the line-of-sight path loss between two points from the distance and frequency you enter.
Use the Radar Range Resolution Calculator for quick radar range resolution estimates in RF, radar, and communications work.
Use the Unambiguous Range Calculator for quick unambiguous range estimates in RF, radar, and communications work.
Use the Pulse Repetition Interval Calculator for quick pulse repetition interval estimates in RF, radar, and communications work.