Why Is My 5G Slower Than 4G? The Real Explanation
Your phone shows “5G” but your speed test returns slower results than 4G LTE. This is confusing but has a logical explanation — not all 5G is the same. Test your mobile speed at instantspeedtest.net/ on both networks to document the difference.
5G Spectrum Types — Why Results Vary Dramatically
| 5G Type | Spectrum Band | Typical Speed | Range | Likely Faster Than 4G? |
|---|---|---|---|---|
| Low-band 5G (Sub-1 GHz) | 600–850 MHz | 30–100 Mbps | Miles | Often No (similar to 4G LTE) |
| Mid-band 5G (Sub-6 GHz) | 2.5–3.7 GHz | 100–400 Mbps | 1–2 miles | Yes |
| High-band 5G (mmWave) | 24–47 GHz | 1–4 Gbps | Feet to meters | Dramatically yes |
The Low-Band 5G Problem — T-Mobile and AT&T Nationwide Coverage
When carriers advertise “nationwide 5G coverage” on TV, they primarily mean low-band 5G deployed on refarmed 4G spectrum (600–850 MHz). Low-band 5G can actually be slower than existing 4G LTE because it uses narrower channels on congested spectrum. T-Mobile’s 600 MHz 5G and AT&T’s 850 MHz 5G sometimes test slower than their 4G LTE bands because: (1) the 5G channel may be narrower than the 4G channel on the same tower; (2) early modem implementations had inefficiencies; and (3) 4G LTE has years of optimization. Verizon’s mmWave 5G and T-Mobile’s mid-band C-band are genuinely fast — but only available in dense urban areas. Check your carrier’s coverage map for C-band or mmWave availability at your location. See our T-Mobile Home Internet guide.
Related Guides
- T-Mobile Home Internet Speed
- Starlink vs 5G Home Internet
- Mobile Hotspot Speed Test
- Good Speed for Hotspot
- Does Weather Affect Internet Speed?
- How to Test Mobile Internet Speed
Frequently Asked Questions
Should I switch from 5G to LTE for better speeds?
If your 5G consistently tests slower than 4G LTE on the same carrier, yes — forcing LTE is a legitimate solution. On Android: Settings → Mobile Network → Network type → LTE only. On iPhone: Settings → Cellular → Cellular Data Options → Voice & Data → LTE. This forces your phone to use 4G. Check speeds monthly as carriers continue deploying mid-band 5G — the balance often shifts as infrastructure improves.
Why does indoor 5G perform poorly?
High-band 5G mmWave can’t penetrate walls — it’s a line-of-sight technology. Mid-band 5G penetrates buildings reasonably but loses speed. Low-band 5G penetrates best. Inside buildings, your phone often falls back to 4G LTE because it provides better indoor performance than the 5G bands available at your location. This is an inherent physics limitation, not a network configuration issue.