We've deployed over 30,000 devices on NB-IoT and LTE-M combined — across Europe, India, and the Middle East. On paper, these two technologies look similar. In the field, they're completely different animals. Here's the decision framework we use with every client.

The one-line difference

NB-IoT is a postcard. Cheap to send, reliable, but you can only fit a few sentences. LTE-M is a phone call. More expensive per message, but you can have a real conversation.

NB-IoT: 200 kHz channel, ~60 kbps max, no handover between cell towers, extraordinary deep-indoor coverage. LTE-M: 1.4 MHz channel, up to 1 Mbps, full mobility with handover, VoLTE support.

That's the technical spec. Here's what it means in practice.

NB-IoT: the meter and sensor protocol

Static devices. Small payloads. Infrequent transmissions. Water meters in basements, structural sensors on bridges, soil probes in fields. These devices send less than 200 bytes every 15-60 minutes, never move, and need to run for years on a battery.

Our water meter deployments hit 8+ years on a 6,000 mAh battery with hourly reporting. The deep coverage means devices work in underground utility vaults where LTE-M can't reach.

The power trick: PSM (Power Saving Mode) lets the device sleep for hours, drawing under 5 microamps. The network remembers it's registered and pages it when there's a downlink message. The device doesn't waste power maintaining a connection.

LTE-M: for things that move or talk back

Asset trackers on trucks. Wearable health monitors. EV chargers. Connected vending machines. Anything that moves between cell towers, needs firmware updates, or requires real-time responsiveness.

LTE-M's handover means a vehicle tracker doesn't drop connection at cell boundaries. The higher bandwidth makes OTA updates practical — a 256 KB firmware push takes seconds on LTE-M, versus 40+ minutes with retransmissions on NB-IoT.

And latency. NB-IoT round-trip: 1.5-10 seconds. LTE-M: 50-100ms. If your device needs to respond to a command quickly — unlock a door, trigger an alarm, update a display — NB-IoT's latency is a non-starter.

The carrier problem (and our recommendation)

None of this matters if your carrier doesn't support the protocol. NB-IoT is strong in Europe and China, patchy in North America. LTE-M is broader in North America and Australia.

For global products, here's what we tell every client: design the hardware for both. Modules like the Quectel BG96 and Nordic nRF9160 support NB-IoT and LTE-M on the same chipset. Same BOM cost. You select the protocol per deployment region in firmware configuration.

We've been doing this for three years now. Not once has a client regretted the dual-mode approach. Several have been saved by it when carrier plans changed mid-deployment.

Key Takeaways

• NB-IoT for static sensors with small payloads and deep coverage needs
• LTE-M for mobile assets, real-time responsiveness, and devices needing OTA updates
• Always design hardware for both — dual-mode modules cost the same and save you from carrier risk
• Verify actual carrier coverage in your target markets before you commit. Don't trust coverage maps.