How to Increase Upload Speed: Step-by-Step Fixes

Why Upload Speed Is Often the Real Bottleneck

Most internet plans — especially cable — are asymmetric: fast download, slow upload. Xfinity's 300 Mbps plan, for example, typically delivers 15–20 Mbps upload. This was fine when people only consumed content, but video calls, cloud backups, content creation, and remote work all depend heavily on upload. Here's how to maximize what you have.

Step 1: Check What's Using Your Upload Bandwidth

Before tuning anything, find out if a background process is consuming your upload:

Windows: Open Task Manager (Ctrl+Shift+Esc) → Performance tab → Open Resource Monitor → Network tab. Sort by "Send" to see which apps are uploading most.

macOS: Open Activity Monitor → Network tab. Sort by "Sent Bytes."

Common upload bandwidth hogs:

Step 2: Use Ethernet Instead of WiFi

WiFi's half-duplex nature disproportionately hurts upload. A wired Ethernet connection eliminates this and typically doubles upload speed in our testing. If you're on a video call that's choppy despite decent plan speed, plug into Ethernet — this single change often resolves the issue.

Step 3: Enable QoS for Upload Traffic

Quality of Service (QoS) lets you tell your router which upload traffic gets priority. For video calls, enable QoS and prioritize the apps you care about:

1. Log in to your router admin panel (usually 192.168.1.1 or 192.168.0.1).
2. Find QoS settings — usually under "Advanced," "Traffic Management," or "QoS."
3. Set your video call app (Zoom, Teams, Google Meet) to highest priority.
4. Set cloud backup apps to lowest priority.

See our full QoS setup guide for step-by-step instructions by router brand.

Step 4: Test Upload Speed Accurately

Run a speed test from Ethernet, not WiFi, with all background apps closed. This gives you your true plan upload speed. If the result is significantly lower than your plan's advertised upload:

• Check the modem — connect a device directly to the modem (bypassing the router) and test again. If upload improves, the router may be the bottleneck.
• Check for ISP throttling — some ISPs throttle upload speeds during peak hours. Test at different times of day.
• Call your ISP with documented speed test results if upload consistently falls short of your plan.

Step 5: Upgrade Your Plan or Technology

If you've done everything above and upload speed is still inadequate, the limiting factor is your plan. Cable's DOCSIS 3.1 technology caps upload far below download by design. Your options:

If fiber is available at your address, the upload improvement alone often justifies switching — especially for remote workers and content creators. Check fiber availability using our fiber by state report.