Calculating total usage for SIM

My application will be publishing data that contains 12-byte records. There will be a maximum of 50 records per day resulting in around 180k of data per month.

What overhead data would be added to this? Or do we only pay for actual data sent.

ie. If the data is sent in real time as it becomes available on the device would there be an overhead for each publish and I would need to instead save up records and maybe only publish every hour or do I not have to worry about this ?

Thanks

There’s information here:

https://docs.particle.io/guide/getting-started/data/electron/

https://docs.particle.io/reference/firmware/electron/#cloud-functions

Thanks Kenneth,
Seems the weekly min handshake + Turn ON/Reset overhead + 23 minute pings will use up the first MB before I send any data. My expected max. data is less than 200k per month so if I allow 2MB-3MB per device per month then I should be covered.

The frame overhead with ack is around 122 bytes (around 5 times the number of bytes in my message). However, the messages are events and need to be send close to real time.