Why is my download speed slower than my plan?

Common reasons real download speeds fall below what your provider advertises, and how to narrow down the cause with a live speed readout.

You pay for 500 Mbps and a download seems to crawl at 20 MB/s. Before blaming the provider, check the common causes. Many of them are on your side of the router.

First, check the units

500 Mbps is about 62.5 MB/s at best. If your tool shows MB/s, compare like with like using the conversion table.

Common causes

1. The server is the limit. A download can only go as fast as the sending server allows. Try another large file from a different site.
2. Wi-Fi is the limit. Distance, walls and interference slow wireless links. Try a cable.
3. Other devices are busy. Streaming, game updates and cloud backups share the same connection.
4. Background apps on your PC. Updates and sync tools can use bandwidth at the same time.
5. A VPN. Encryption and a distant server can reduce speed.
6. An old router, cable or port. A 100 Mbps network port cannot reach gigabit speeds.

Use a live readout to separate causes

Keep an eye on the taskbar readout during a download.

• If download speed is steady and below your plan, the limit is probably the server or the link.
• If the speed jumps up and down, something else is competing for bandwidth. See find which app is using your internet.
• If upload is high while you download, a backup or sync may be running.

Then test

A speed test measures the ceiling of your connection to a test server. Run one with other devices idle. If the test hits your plan speed but real downloads do not, the bottleneck is elsewhere. If neither does, contact your provider. The slow internet checklist gives the order of checks.

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Published 2026-10-17