Yagi Antenna Element Calculator
Starting dimensions for a 2–12 element Yagi — reflector, driven element, directors, spacing, boom length and gain estimate.
These are proven STARTING dimensions — a Yagi's feedpoint drops to ~20–25 Ω when optimised, so plan a gamma match or folded-dipole driven element for 50 Ω coax. Element diameter matters (thicker = trim shorter); metal booms require a boom correction. Model in 4nec2/EZNEC and tweak director lengths for the gain/F-B trade-off you want.
Yagi Antenna Calculator computes starting element lengths, spacing and boom length for a 2–12 element Yagi — free, instant and private in your browser. Ham operators, TV-antenna builders and meshtastic/LoRa range-pushers use it to skip the datasheet algebra: type your numbers, read the answer with the substituted formula shown step by step, and share an exact permalink of the calculation.
About Yagi Antenna Element Calculator
Yagi Antenna Calculator computes starting element lengths, spacing and boom length for a 2–12 element Yagi using the standard engineering relation: reflector 0.495λ, driven 0.473λ, directors ~0.440λ shortening ~1.5 % each, spacing 0.125λ. Worked live: a 3-element 145 MHz Yagi: 102/98/91 cm elements on a 52 cm boom, roughly 7 dBi. The result recalculates on every keystroke, the worked-example panel shows your numbers substituted into the formula, and the Copy permalink button encodes the inputs in the URL so a colleague opens exactly your calculation. Everything runs client-side — nothing you type leaves your device.
How to use Yagi Antenna Element Calculator
- 1Enter your values — the tool starts with realistic defaults for this exact use case, so the worked example is meaningful immediately.
- 2Read the live result and the worked-example panel, which substitutes your numbers into the formula step by step.
- 3Adjust any input to compare scenarios, then use Copy result or Copy permalink to share the calculation.
Why use Yagi Antenna Element Calculator?
- ✓Implements the real formula — reflector 0.495λ, driven 0.473λ, directors ~0.440λ shortening ~1.5 % each, spacing 0.125λ — with the substitution shown, not a black box
- ✓Built for ham operators, TV-antenna builders and meshtastic/LoRa range-pushers
- ✓Copy result and permalink buttons — share the exact calculation in a README, forum answer or design review
- ✓100% free, no sign-up, runs entirely in your browser (works offline once loaded)
Frequently asked questions
How do you calculate yagi antenna?+
Starting element lengths, spacing and boom length for a 2–12 element Yagi follows reflector 0.495λ, driven 0.473λ, directors ~0.440λ shortening ~1.5 % each, spacing 0.125λ. For example, a 3-element 145 MHz Yagi: 102/98/91 cm elements on a 52 cm boom, roughly 7 dBi. The calculator applies the same relation and shows the substituted arithmetic so you can verify every step.
How much gain does each added director give?+
Diminishing returns: 3 elements ≈ 7 dBi, then roughly +1 dB per director early on, falling as the boom grows — doubling boom length adds only ~2.5 dB. Long Yagis trade enormous booms for the last few dB, which is why stacking two short ones is often smarter.
Why is my Yagi's SWR terrible when the lengths are right?+
Parasitic elements drag the driven element's feed impedance down to 20–25 Ω. That's expected — match it with a gamma match, hairpin, or a folded-dipole driven element (4× impedance step-up). The dimensions here are starting values; trim directors to tune.
Is the Yagi Antenna Calculator free and private?+
Yes — completely free with no sign-up or usage limits, and it runs entirely in your browser: the values you enter are never uploaded or stored on a server.
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