Ever noticed lag during gaming, slow downloads, or weird connection drops? Sometimes, the culprit isn’t your internet speed but the MTU size (Maximum Transmission Unit). MTU determines the largest packet size your network adapter can send. If it’s too high or too low, you may face connectivity issues.
In this guide, I’ll show you exactly how to change MTU size in Windows 11, why it matters, and what the best MTU size is for your setup.
What is MTU Size and Why Does It Matter?
MTU (Maximum Transmission Unit) is the maximum size of a data packet that can be sent over your network.
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Too high MTU → Packets may get fragmented, causing lag or dropped connections.
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Too low MTU → More packets than necessary, slowing things down.
Think of MTU like shipping boxes: too big, and they won’t fit through the door; too small, and you’ll waste time making too many trips.
When Should You Change MTU Size?
You might want to tweak MTU if:
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Online games keep lagging or disconnecting.
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Certain websites don’t load fully.
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VPNs or remote desktops drop frequently.
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Speed tests show inconsistent results.
How to Check Current MTU Size in Windows 11
Step 1: Open Command Prompt
Press Windows + S, type cmd, right-click Command Prompt, and select Run as administrator.
Step 2: Enter Network Interface Command
Type:
This will display all network interfaces and their current MTU values.
How to Change MTU Size in Windows 11
Method 1: Using Command Prompt (Quickest Way)
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Open Command Prompt as Administrator.
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Find your network name (e.g., Wi-Fi, Ethernet) from the previous step.
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Run the following command:
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Replace Wi-Fi with your actual network name.
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Replace 1500 with your desired MTU value.
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Press Enter and restart your computer.
Method 2: Using Windows PowerShell
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Open PowerShell (Admin) by right-clicking the Start menu.
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Enter this command to check current MTU:
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To change MTU, use:
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Replace Wi-Fi with your adapter name.
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Change 1500 to your desired MTU.
Method 3: Changing MTU via Registry Editor (Advanced Users)
⚠️ Warning: Editing the registry can cause issues if done incorrectly. Back up before making changes.
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Press Windows + R, type
regedit, and hit Enter. -
Navigate to:
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Find your network adapter (look for IP address details).
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Right-click → New > DWORD (32-bit) Value → Name it
MTU. -
Set the value (Decimal format) → e.g.,
1500. -
Restart your PC.
How to Find the Best MTU Size for Your Connection
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Open Command Prompt (Admin).
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Type this command, replacing example.com with a reliable site (like Google):
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If you get Packet needs to be fragmented, lower the value (e.g., 1464, 1452).
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Add 28 to the highest successful value to get the best MTU.
Example: If 1472 works, MTU = 1472 + 28 = 1500.
Common MTU Values
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1500 – Default for most Ethernet/Wi-Fi connections.
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1492 – Common for PPPoE (DSL connections).
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1472 or lower – Sometimes needed for VPNs.
Troubleshooting After Changing MTU
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Internet stopped working? Reset MTU back to default:
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Still lagging? Try lowering MTU step by step.
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Using a router? Change MTU on the router too, so it matches your PC.
Conclusion
Changing the MTU size in Windows 11 can make a huge difference in fixing lag, dropped connections, or browsing issues. The process is straightforward using Command Prompt or PowerShell. Just remember—test your ideal MTU with the ping method before making it permanent.
A well-adjusted MTU is like finding the perfect-sized box for shipping—it saves time, reduces errors, and keeps everything running smoothly.
FAQs
1. What is the default MTU size in Windows 11?
Usually, it’s 1500 bytes for Ethernet and Wi-Fi connections.
2. Will changing MTU improve my gaming performance?
Yes, if your current MTU is mismatched. It can reduce latency and packet loss.
3. Can I set different MTU sizes for Ethernet and Wi-Fi?
Yes, you can configure them separately for each adapter.
4. Is it safe to change MTU size?
Yes, as long as you use valid values (commonly 1400–1500). Just avoid extremely low numbers.
5. How do I reset MTU back to default?
Run:
Then restart your PC.