3G Speeds Explained: From 144 kbps to 42 Mbps

One table, four stages of the 3G family: the IMT-2000 baseline, the HSDPA steps and the dual-carrier HSPA+ ceiling.

The original 3G promise was written into IMT-2000 as three speed classes: 144 kbps for a user in a moving vehicle, 384 kbps for a walking user and 2 Mbps for a stationary device indoors. These were peak targets, not guarantees, and every user in a cell shares the same 5 MHz W-CDMA carrier running at 3.84 Mcps.

HSDPA was the first big upgrade. Downlink peaks started at 3.6 Mbps, then rose to 7.2 Mbps and 14.4 Mbps as handsets gained support for faster modulation — all on the same 5 MHz carrier, so no new spectrum was needed for each step.

Dual-carrier HSPA+ bonds two 5 MHz carriers and peaks at 42 Mbps. Some carriers sold this as 4G, but it belongs to the 3G family tree: an evolution of UMTS, not a new radio system.

LTE Category 4 reaches 150 Mbps downlink on a 20 MHz carrier — about 3.5 times the HSPA+ ceiling. That gap explains why carriers refarm 3G spectrum: the same bandwidth simply carries more data on 4G.

To place your own device, find its spec sheet and look for the highest listed data class: 'HSDPA 14.4' or 'HSPA+ 42' tells you the ceiling, and the absence of LTE tells you the phone is 3G-only. Cross-check that result against the dates on the 3G Shutdown Schedule page before relying on it.

• 144 kbps — IMT-2000, moving vehicle
• 384 kbps — IMT-2000, walking user
• 2 Mbps — IMT-2000, stationary indoors
• 3.6 / 7.2 / 14.4 Mbps — the HSDPA steps
• 42 Mbps — dual-carrier HSPA+
• 150 Mbps — LTE Category 4 on a 20 MHz carrier

Further reading

• 3G Shutdown Dates and What Replaces It
• UMTS Frequency Bands: 2100 MHz and 900 MHz