Packet Size on LoRa Networks - Structure of Network Pricing

Updated at January 27th, 2023

Table of Contents

How much data do the devices use per month?

There are several ways network providers could calculate packet size from a device causing differences in pricing structure.

Depending on the pay structure, some networks might round to the nearest whole number
It’s also possible to charge for the entire on-air packet, which is a suggestive 24 bytes long
- Packets starts with a preamble and hardware layer LoRa header that is undocumented and generally not counted by networks (20.25 bytes)
- 8 – 23 bytes of LoRaWAN header (depending on number of mac commands going up)
- An optional port number (1 byte)
- User payload for that port (11 bytes max in most restrictive regions)
- 4 bytes of CRC
- So the total size for an 11 byte payload, not including the initial preamble, is 8 + 1 + 11 + 4 = 24 bytes

This depends on a few factors:

Keep in mind:

The minimum connection charge could have a massive effect on the data usage. Consider Helium. Helium provides connectivity through the purchase of data credits. Each data credit equals a 24 byte packet. Helium only calculates based on the payload itself but rounded up to the nearest data credit.
As a general rule of thumb you would expect to use 1 data credit on Helium for each uplink on the Oyster

The PDF attachments found below contain the payload structure for the different LoRaWAN devices.