433 MHz Antenna Length Calculator
The 17 cm wire that transforms cheap 433 MHz modules — exact quarter-wave and dipole lengths for ISM-band remotes, LoRa 433 and RC links.
Preset: quarter wave at 433.92 MHz → ~16.4 cm (cut 17.3 cm and trim). Solder it vertical, add a 17 cm counterpoise wire from GND, and re-test range before blaming the module.
433 MHz Antenna Length Calculator computes the quarter-wave and dipole wire lengths for 433.92 MHz ISM modules, RF remotes and LoRa-433 — free, instant and private in your browser. Arduino/ESP32 builders using 433 MHz remotes, sensors and LoRa-433 links 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 433 MHz Antenna Length Calculator
433 MHz Antenna Length Calculator computes the quarter-wave and dipole wire lengths for 433.92 MHz ISM modules, RF remotes and LoRa-433 using the standard engineering relation: λ = c/f = 69.1 cm at 433.92 MHz; L(¼-wave) = 0.25·λ·k ≈ 16.4 cm. Worked live: soldering a 16.4–17.3 cm vertical wire to a bare FS1000A module's ANT pad routinely multiplies range 10×. 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 433 MHz Antenna Length 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 433 MHz Antenna Length Calculator?
- ✓Implements the real formula — λ = c/f = 69.1 cm at 433.92 MHz — with the substitution shown, not a black box
- ✓Built for Arduino/ESP32 builders using 433 MHz remotes, sensors and LoRa-433 links
- ✓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 433 mhz antenna length?+
The quarter-wave and dipole wire lengths for 433.92 MHz ISM modules, RF remotes and LoRa-433 follows λ = c/f = 69.1 cm at 433.92 MHz; L(¼-wave) = 0.25·λ·k ≈ 16.4 cm. For example, soldering a 16.4–17.3 cm vertical wire to a bare FS1000A module's ANT pad routinely multiplies range 10×. The calculator applies the same relation and shows the substituted arithmetic so you can verify every step.
Is 16.4 cm or 17.3 cm the right length for 433 MHz?+
17.27 cm is the bare textbook quarter wave (λ/4); real thin wire resonates ~5 % short of theory due to end effect, giving 16.4 cm. Practical method: cut 17.3 cm, and if you can measure SWR or range, trim toward 16.4. Either beats the module's bare pad by an order of magnitude.
Why does my 433 MHz receiver need an antenna too?+
Reciprocity — receive antennas obey the same resonance physics, and superregenerative receiver modules (the green RXB types) are deaf without one. Give both ends a quarter wave: matched antennas at TX and RX compound, which is how a 10 mW link crosses a property instead of a room.
Is the 433 MHz Antenna Length 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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