LTE-M vs NB-IoT: which low-power network for your device?

LTE-M and NB-IoT are the two low-power cellular technologies built for IoT devices that send small amounts of data and run for years on a battery. Both are part of the 4G family, both reach places ordinary 4G struggles with, and every ThingSIM supports both. Which one a device uses is decided by its modem, so the choice is really a choice of device.

The short version

	LTE-M (Cat-M1)	NB-IoT
Data rate	Higher: enough for firmware updates and frequent reports	Very low: small, infrequent messages
Moving devices	Handles movement between cells	Best for devices that stay in one place
Voice	Possible (VoLTE) on supporting devices	No
Latency	Lower	Higher
Battery life	Long	Longest
Coverage in buildings and underground	Better than standard 4G	Deepest
Typical devices	Trackers, wearables, alarm communicators, vending	Meters, level and environmental sensors, parking sensors

When LTE-M is the better fit

Choose an LTE-M device when it moves, needs to respond quickly, sends more than a few readings a day, or needs firmware updates over the air without taking hours. Asset trackers and anything that might need a voice path are the classic cases.

When NB-IoT is the better fit

Choose an NB-IoT device when it stays put, sends small readings infrequently, and must run for years on a battery, often somewhere radio struggles to reach: a meter in a basement, a sensor in a manhole, a logger in a plant room.

Check the device, not the SIM

The SIM does not decide which technology is used; the device's modem does. Look in the specification for “LTE Cat-M1” or “Cat-M” and “NB-IoT” (sometimes “Cat-NB1” or “Cat-NB2”). Many modules support both, plus standard 4G as a fallback. Confirm with the device supplier how it is configured to use them in the UK before a large deployment.

Data use

Both suit small plans. Most low-power sensors and meters fit the 50 MB plan, at £0.90 a month on UK 4-network; see how much data your device needs.

Common questions

Does ThingSIM support LTE-M and NB-IoT?

Yes. Every ThingSIM supports LTE-M and NB-IoT as well as 4G data, 2G and SMS. The device's modem decides which it uses.

Is LTE-M the same as Cat-M1?

Yes. LTE-M is the common name for the LTE Cat-M1 category, sometimes shortened to Cat-M.

Which is better for a GPS tracker, LTE-M or NB-IoT?

Usually LTE-M, because trackers move between cells and often need to report more often than NB-IoT is designed for. See choosing a SIM for a GPS tracker.

Is NB-IoT the same as 5G?

NB-IoT and LTE-M are 4G-family technologies that are also recognised as part of 5G's plans for massive IoT, so devices built for them are expected to remain usable as networks move on.