Radar Range Calculator

Calculate maximum detection range using the radar range equation and received power at any specified range.

What is the Radar Equation?

Radar works like shouting in a canyon and listening for the echo — it sends out a radio pulse and waits for it to bounce back from an object. The further away the target, the weaker the echo that returns. The radar equation calculates exactly how far away you can still hear that echo.

Why it matters: Air traffic control radars must reliably detect aircraft 200+ miles away. Engineers use this equation to choose the right antenna size, transmit power, and sensitivity to ensure nothing slips through undetected.

Radar Parameters
Transmitter, antenna, and target parameters.
W

How loud the radar shouts — more power means farther range. Typical pulse radars: 1 kW – 1 MW

dBi

How focused the beam is — like a flashlight vs. a floodlight. Higher gain = longer range

GHz

X-band ≈ 9.5 GHz (ships/aircraft), S-band ≈ 3 GHz (weather), L-band ≈ 1.3 GHz (air traffic)

m²

How big the echo is — a stealth fighter reflects less than a cargo plane. Fighter ≈ 1–5 m², drone ≈ 0.01 m²

dBm

How quiet an echo the receiver can still hear — lower (more negative) is better

dB

Signal lost to cables, atmosphere, and processing — reduces effective range

Received Power at Range
Calculate Pr at a specified range.
km
Radar Results
Maximum detection range and signal analysis.
Maximum Range12.6km(7.8 miles · 6.8 nmi)

Pr at 50 km = -133.9 dBm

23.9 dB below sensitivity — target not detectable

Wavelength

3.2 cm

R_max

12.60 km

TX Power

1000 W

Antenna Gain

30 dBi

RCS (σ)

1 m²

System Losses

3 dB

This uses the free-space monostatic radar equation. Real radar performance is also affected by pulse compression, Doppler processing, clutter, and atmospheric refraction.