Free tool · LoRaWAN
LoRaWAN airtime calculator
LoRaWAN packet airtime depends on Spreading Factor (SF), Coding Rate (CR), payload size and bandwidth (125 kHz for EU868/US915). This tool applies the Semtech AN1200.13 formula and tells you how many messages per hour you can send while respecting the 1% EU868 duty cycle (or US915 400 ms dwell time).
Free · no sign-upLast updated: 2026-05-20
1 to 242 bytes depending on SF and region
8 by default (Semtech)
Result
- Airtime
- 370.7 ms
- Effective bitrate
- 977 bps
- Max messages/hour
- 97
- Regulatory limit
- 1 % / hour (ETSI)
Assumptions: explicit header (LoRaWAN), CRC on, low data rate optimize on for SF ≥ 11, antenna 14 dBm ERP.
How to use
1. Pick your region (EU868 default for Europe, US915 for North America).
2. Enter the application payload size (without the LoRaWAN MAC header — typically 10-50 bytes).
3. Adjust the SF for desired range (SF7 = ~5 km urban, SF12 = ~15 km but 32× airtime).
4. Keep CR = 1 (4/5) by default; CR = 4 (4/8) only for very noisy environments.
5. Verify that messages/hour is enough for your use case.
Practice now
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