What is a Yagi-Uda antenna?

A Yagi-Uda antenna is a directional antenna array consisting of a driven element (dipole), one reflector behind it, and one or more directors in front. The parasitic elements (reflector and directors) focus the radiation into a beam, increasing gain in the forward direction.

How accurate are these calculations?

The dimensions use the widely published Yagi design coefficients (based on NBS/ARRL tables and optimized Yagi research). They provide a solid starting point. Final optimization with an antenna analyzer or NEC2 simulation software is recommended for critical applications.

What material should I use for the elements?

Aluminum tubing or rod is the most common choice for its low weight and good conductivity. The diameter of the element affects the optimal length slightly; thinner elements (smaller diameter-to-wavelength ratio) need to be trimmed slightly longer. This calculator uses standard thin-element assumptions.

What gain can I expect from a Yagi?

A 3-element Yagi typically yields around 7-8 dBd of gain. Each additional director adds roughly 1 dB. A 10-element Yagi can achieve 14-15 dBd. These are theoretical maximums; real-world gain is slightly lower due to losses and construction tolerances.

What is the driven element and how do I feed it?

The driven element is the active dipole connected to your feedline. It is typically a folded dipole or a split dipole with a balun. The calculator gives its total length; for a split dipole, cut it in half at the center feed point.

Can I use this calculator for Wi-Fi Yagis?

Yes. Enter 2400 MHz for 2.4 GHz Wi-Fi or 5800 MHz for 5.8 GHz. The resulting elements will be very short (a few centimeters), so precision cutting is important at these frequencies.

Yagi Antenna Calculator

Name: Yagi Antenna Calculator
Availability: InStock
Author: Nham Vu

Enter your target frequency and number of elements to get optimized Yagi-Uda antenna dimensions instantly.

Antenna Parameters

Frequency (MHz)

Common: 144 MHz (2m), 432 MHz (70cm), 2400 MHz (Wi-Fi)

Number of Elements

2 = reflector + driven; 3+ adds directors

Velocity Factor

0.95 for thin aluminum rod; 1.0 = free space

Band Quick-Select

Set frequency and element count, then click Calculate.

Results include element lengths and boom spacing.

Frequency

Wavelength

Boom Length

Est. Gain

Element Dimensions

Element	Type	Length (mm)	Length (cm)	Length (in)	Pos. from Refl. (mm)

Antenna Diagram (top view, not to scale)

Design Notes

Copied!

Summary

Enter your target frequency and number of elements to get optimized Yagi-Uda antenna dimensions instantly.

How it works

Enter the target center frequency in MHz.
Select the number of antenna elements (2 to 12).
The calculator derives the free-space wavelength from the frequency.
Each element length is computed as a fraction of the wavelength using established Yagi design coefficients.
Element spacing along the boom is calculated using standard spacing ratios.
Results are displayed as a table with lengths in mm, cm, and inches plus total boom length.

Use cases

Designing a ham radio Yagi beam antenna for VHF or UHF bands.
Building a high-gain TV receiving antenna for a specific channel frequency.
Planning a point-to-point Wi-Fi link antenna for 2.4 GHz or 5.8 GHz.
Academic study of antenna design and electromagnetic wave propagation.
Verifying dimensions of a commercial Yagi against published specifications.
Cutting elements to length before assembling a homebrew antenna project.
Estimating gain and front-to-back ratio for a given element count.
Scaling an existing design to a different operating frequency.

Frequently Asked Questions

Last updated: 2026-06-11 · Reviewed by Nham Vu