Why is my mobile data so slow?

Mobile data is usually slow for one of four reasons: a weak signal where you are, a crowded cell tower, your plan's priority (many plans are deprioritized during congestion or slowed after a data threshold), or a setting on your phone such as Low Data Mode, a VPN or a stuck network mode. A couple of speed tests in different places and at different times tell you which one it is.

Find the cause in five minutes

Run a speed test on mobile data with Wi-Fi turned off, and note download, upload and ping. Then change one thing at a time:

Try this	If speed jumps	Likely cause
Go outside or near a window	Much faster outdoors	Weak indoor signal
Test again at a quiet hour (early morning)	Much faster off-peak	Congestion at the cell
Test on Wi-Fi	Wi-Fi fast, mobile slow	The mobile network or your plan, not the phone
Compare with a friend's phone on the same carrier, same spot	Theirs is faster	Your plan, phone or settings
Turn off the VPN or Low Data Mode	Faster	Phone settings

Our mobile data speed test guide explains how to get clean readings on a phone.

Weak signal

Mobile signal falls off quickly through walls, basements, metal roofs and energy-efficient glass. A phone at the edge of coverage spends more effort on each transmission and gets less speed. Upload usually suffers first.

Coverage maps can be misleading here. Ofcom, for example, counts an area as having 4G coverage if a phone has a 95% chance of reaching at least 2 Mbit/s, according to its Connected Nations 2025 report. "Covered" can mean much slower than you'd expect, and maps usually describe outdoor signal.

If signal is the problem at home, Wi-Fi calling, a different carrier with a closer mast, or a carrier-supplied signal booster are the realistic fixes.

Congestion at the tower

Every phone near a cell site shares its capacity. At stadiums, stations, festivals and busy downtown areas, and in residential areas in the evening, speeds can drop sharply even with full bars. If tests are fast at 7 a.m. and slow at 8 p.m. in the same spot, it's congestion. There's no setting to fix it. Your options are a carrier with more capacity locally, Wi-Fi where you can, or a higher-priority plan.

Your plan's priority and limits

Carriers don't treat all plans the same during congestion. Cheaper plans, prepaid brands and carriers that resell a bigger network's capacity are often given lower priority. That's called deprioritization. Many unlimited plans also include a set amount of "premium" or "priority" data each month and drop you to a lower priority after that. Some plans also slow you to a very low speed once you pass a hard data cap.

Verizon's network performance page shows how much the plan matters on one network. It lists typical 5G/4G LTE download speeds of 35–148 Mbps for most of its mobile plans, against 20–148 Mbps for its Unlimited Welcome plan. It also says it streams video to smartphones at 480p or 720p depending on the plan.

How to check:

• Open your carrier's app and look at data used this billing cycle and any "premium data" allowance.
• Notice whether speed fell suddenly partway through the month, then came back on your renewal date.
• Read your plan's network management or "video streaming" terms.

If video is the only thing that's slow while speed tests look normal, your plan may be capping video resolution rather than overall speed. ISP throttling explains how to tell throttling from congestion.

Settings on your phone

Several settings quietly limit mobile data:

• Low Data Mode (iPhone) or Data Saver (Android) limits background activity and can lower streaming quality. On iPhone it's under Settings > Cellular > Cellular Data Options. On Android it's usually under Network & internet.
• A VPN routes everything through a distant server, which adds delay and can cut speed. Disconnect and retest. See does a VPN slow your internet?
• Network mode. Make sure it's set to automatic or 5G/LTE, not 3G or a restricted mode.
• Outdated software. Update the phone. On iPhone, a carrier settings update may also be offered under Settings > General > About.
• Stuck connection. Turn airplane mode on for ten seconds, then off. If that doesn't help, restart the phone.
• SIM or eSIM issues. If problems began after a phone swap, reseat the SIM or ask the carrier to reissue the eSIM.

As a last step, reset network settings. You'll need to re-enter Wi-Fi passwords afterward.

Why 5G can feel no faster than 4G

"5G" covers very different networks. Low-band 5G reaches far but often performs much like 4G. Mid-band and millimeter-wave 5G are much faster but cover smaller areas. Verizon, for example, lists typical download speeds of 163–622 Mbps on its 5G Ultra Wideband network, against 35–148 Mbps on its wider 5G/4G LTE network for most plans. A 5G icon alone doesn't tell you which you're on.

If your phone keeps jumping between a weak 5G signal and 4G, it can be slower than staying on 4G. Test with 5G on and off in the same spot and keep whichever is faster.

When the phone's speed test is fine but apps are slow

If the test shows good download and upload but apps feel sluggish, the cause is more likely high ping, packet loss or the app's own servers. Our guide to a speed test that's fast while the internet feels slow covers those causes. If it's only one app, check its permissions for mobile data. Both iPhone and Android let you turn off mobile data per app, and that's easy to forget.