A subnet mask is a key parameter that determines which IP addresses are part of your local network. Without it, it's impossible to properly configure a static IP address, forward ports, or connect network equipment. But where can you find it? In most cases, the Wi-Fi subnet mask is hidden in the router or operating system settings, and users don't even know how to quickly find it.
This article will help you figure out how to find your Wi-Fi subnet mask on any device—from a laptop to a smartphone. We'll cover methods using the graphical interface, the command line, and even mobile apps. We'll also explore why the default mask 255.255.255.0 It is not suitable for all networks and when it needs to be changed.
What is a subnet mask and why is it needed?
Subnet mask (or network mask) is a 32-bit number that divides an IP address into two parts: the network identifier and the host identifier. For example, in the address 192.168.1.100 with a mask 255.255.255.0 the first three octets (192.168.1) denote the network, and the last (100) — a specific device.
Without the right mask:
- 🔌 Devices will not be able to exchange data on the local network
- 🖥️ I can't set up a static IP for my printer or IP camera.
- 🌐 There will be problems with port forwarding for game servers or remote access
Most home networks use a mask. 255.255.255.0 (or /24 (in CIDR notation), but in office or complex configurations it may differ. If you're setting up your network manually, be sure to check this setting with your administrator or in your router documentation.
Method 1: Find out the subnet mask through the router settings
The most reliable way is to view the mask in the router's web interface. To do this:
- Open your browser and enter the router's IP address (usually
192.168.0.1,192.168.1.1or192.168.8.1). - Log in (default logins:
admin/adminoradmin/password). - Find the section
Local Area Network (LAN)orDHCP.
Depending on the router model, the mask may be displayed as:
- 📌
Subnet Mask(on TP-Link, ASUS) - 📌
Subnet mask(on Keenetic, Zyxel) - 📌
Netmask(on MikroTik, Ubiquiti)
If you have a router from a provider (for example, Rostelecom or MTS), the interface may be simplified. In this case, the mask is often hidden in advanced settings or not displayed at all. In this case, use the other methods in this article.
Method 2: View the mask on Windows via the command line
On Windows computers, you can find out the subnet mask in 10 seconds:
- Click
Win + R, entercmdand pressEnter. - Enter the command:
ipconfig /all - Find the block
Wireless Wi-Fi network adapter.
In the results you will see the following lines:
- 🔹
IPv4 address- your current IP - 🔹
Subnet mask— the desired value (for example,255.255.255.0) - 🔹
Main gateway— IP address of the router
If the connection is via cable, look for the block Ethernet adapterPlease note: If you have multiple network adapters (e.g. Wi-Fi + VPN), select the active one (the one with the IP address).
What to do if ipconfig shows 169.254.xx?
This means your device hasn't received an IP address from the router. Check your Wi-Fi connection or reboot the router.
Method 3: How to find the subnet mask on macOS and Linux
On MacBook or Linux computers, the subnet mask is displayed through the terminal. Open it (Applications → Utilities → Terminal on macOS or Ctrl+Alt+T on Linux) and enter:
For macOS:
ifconfig | grep"netmask"Look for the line with inet And netmask for the active interface (usually en0 for Wi-Fi).
For Linux (Ubuntu, Debian, etc.):
ip aor the deprecated command:
ifconfigThe mask will be indicated after inet through a slash (for example, 192.168.1.100/24, Where 24 = 255.255.255.0).
On some Linux distributions (eg. Arch) package installation may be required net-tools for the team ifconfig:
sudo pacman -S net-tools⚠️ Note: On macOS Monterey and later, the commandifconfigcan be replaced bynetworksetup -listallhardwareports. Useman networksetupfor reference.
Method 4: Viewing the mask on Android and iPhone
Mobile devices don't always show the subnet mask in the settings, but there are workarounds.
On Android:
- Install the application WiFi Analyzer or Network Info II.
- Connect to Wi-Fi and open the app.
- Find the section with network information - it will be there
Subnet Mask.
On iPhone/iPad:
- Go to
Settings → Wi-Fi. - Click on the icon
inear your network. - Scroll down to the block
IPv4 address— the mask will be indicated there.
If the mask is not displayed on iOS, use the app Fing or Network AnalyzerThey will show full information about the network, including the mask and gateway.
☑️ Check your mask on your mobile device
Method 5: Using specialized utilities
If standard methods don't work, use professional tools:
| Utility | Platform | How to recognize a mask | Download link |
|---|---|---|---|
| Advanced IP Scanner | Windows | Scans the network and displays the mask in the device information. | Official website |
| Angry IP Scanner | Windows/macOS/Linux | Displays the mask in the scan results. | GitHub |
| Wireshark | All platforms | Analyzes network packets (for advanced users) | wireshark.org |
Suitable for quick analysis Advanced IP Scanner — it doesn't require installation and displays the subnet mask in the first window. If you need more detailed data (for example, to diagnose problems), use Wireshark, but be careful: this is a tool for professionals.
⚠️ Attention: Some antivirus programs (for example, Kaspersky) may be blocked by network scanners. Add the utility to the exceptions list or temporarily disable protection.
Method 6: Calculating a mask using CIDR notation
If you know CIDR notation (For example, /24 or /26), the mask can be calculated manually. Here's the mapping of the most common values:
| CIDR | Subnet mask | Number of IP addresses |
|---|---|---|
/24 |
255.255.255.0 |
256 (254 available) |
/25 |
255.255.255.128 |
128 (126 available) |
/26 |
255.255.255.192 |
64 (62 available) |
Formula for calculation: Mask = 32 binary ones, shifted left by (32 − CIDR). For example, /24 = 11111111.11111111.11111111.00000000 = 255.255.255.0.
For automation, use online calculators, for example:
- IP Calculator from SubnetOnline.com
- CIDR to Mask Converter on Site24x7
Common mistakes and how to avoid them
When working with subnet masks, users often encounter problems:
- 🚫 Mask mismatch on devices: If on the router
255.255.255.0, and on the computer255.255.0.0, the network will not work. All devices must use the same mask. - 🚫 IP address conflict: When manually setting a static IP, make sure it is not the same as other devices and is within the DHCP range.
- 🚫 CIDR errors: Notation
/30provides only 4 IP addresses (2 available), which is not enough for a home network.
To check if the settings are correct, use the command ping:
ping 192.168.1.1If packets don't reach the router, the problem is most likely in the mask or gateway.
⚠️ Warning: Changing the subnet mask on your router without understanding the consequences may result in loss of network access. If unsure, write down your current settings before making any changes.
FAQ: Answers to frequently asked questions
Is it possible to change the subnet mask on a router?
Yes, but this requires caution. Changing the mask will reset all connected devices, and they will have to be configured again. For example, when changing from /24 on /23 The IP address range will expand from 256 to 512, which may cause conflicts.
Why is my mask 255.255.252.0 and not 255.255.255.0?
This means that your ISP or network administrator uses CIDR. /22, which allows you to combine multiple subnets. These settings are suitable for offices or apartment buildings with shared internet.
How can I find out the subnet mask if I don't have access to the router?
Use the methods for your device (eg. ipconfig on Windows or Network Info II (on Android). If you're connected to a network, the mask will appear in your network settings.
What happens if I specify an incorrect mask?
The device will not be able to communicate with the router and other nodes on the network. For example, with a mask 255.255.0.0 instead of 255.255.255.0 traffic will go to another subnet, which will lead to loss of Internet.
Do I need to know the subnet mask for normal Wi-Fi use?
No, in 99% of cases it's configured automatically via DHCP. Knowing the mask is only required for manually setting up static IP addresses, port forwarding, or troubleshooting network problems.