Testing your Cox connection
Cox delivers most of its internet over a cable (DOCSIS 3.1) network, with fibre-fed multi-gig service at some addresses. As on all cable networks, the upload is a small fraction of the download on most tiers, and many plans come with a monthly data allowance of about 1.25 TB.
This test detects your provider automatically and measures download, upload, ping, jitter and latency under load against the nearest server on Cloudflare's network. Enter your plan speed under the result to see the percentage you really get.
Cox speeds by plan
| Plan | Download | Upload |
|---|---|---|
| Essential 100 | 100 Mbps | about 5 Mbps |
| 500 Mbps tier | 500 Mbps | about 10 Mbps, more in upgraded areas |
| Gigablast | up to 1 Gbps | about 35 Mbps |
| 2 Gig (fibre-fed addresses) | up to 2 Gbps | up to 2 Gbps |
Cox renames its tiers often and speeds differ by market. The figures above are the common ones in 2026; your exact upload is printed on your plan's broadband label. Checked on 31 October 2026; tiers change and vary by address, so confirm on the Cox website.
What result should you expect?
On Gigablast, a wired test from a gigabit port should show 900 to 940 Mbps down and about 35 Mbps up. On a 500 Mbps tier, an upload around 10 Mbps is normal for cable. Over Wi-Fi, expect less, especially far from the gateway.
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Common reasons for slow Cox speeds
- Old modem: gig speeds need a DOCSIS 3.1 modem; a DOCSIS 3.0 model limits you.
- Small upload: calls freeze when someone uploads. Check latency under load.
- Evening congestion: see internet slow in the evening.
- Data allowance: heavy use can lead to extra charges on plans with a data cap. Check your usage in your Cox account.
Before contacting Cox support
- Restart the gateway or modem and wait until the online light is steady.
- Run three wired tests at different hours.
- Check the Cox app for outages and run its own diagnostics before calling.
- If speeds stay below your plan, check for traffic throttling, then contact support with your saved results.
More help: slow internet: causes and fixes and all providers we cover.
Sources
SpeedFibre is an independent website, not affiliated with Cox. The provider's name is used only to describe the service being tested.
Frequently asked questions
Does Cox have a data cap?
Many Cox plans include a monthly data allowance of about 1.25 TB, with charges or unlimited-data options beyond it. Check the terms of your plan.
Why is my Cox upload so slow?
Cable networks give most of their capacity to download. Upload speeds of 5 to 35 Mbps are normal on Cox cable tiers; only fibre-fed tiers are symmetrical.
Is Cox Gigablast really 1 Gbps?
Up to 1 Gbps download. A computer with a gigabit Ethernet port will show about 940 Mbps at best, which is a normal result.
