What Number Lock does and why you need to control it

Number Lock is a toggle that switches your keyboard's number pad between two modes. When it is on, the number pad types numbers. When it is off, those same keys move your cursor around the screen — up, down, left, right, and page functions. Most keyboards have a light that shows whether Number Lock is currently on.

You need to control Number Lock because it changes without warning. Your keyboard might arrive with it off, or it might turn off when you restart your computer. If you sit down to type numbers and nothing appears, or if your arrow keys suddenly stop working, Number Lock is usually the culprit. Learning to toggle it takes five seconds and solves the problem when ready.

The method depends on your keyboard type — desktop keyboards, laptop keyboards, and external keyboards all have different approaches. Once you know which one you have, you will recognize the Number Lock key and be able to switch modes whenever you need to.

Key Takeaways

  • Number Lock toggles your number pad between typing numbers and moving your cursor, and a light on the keyboard usually shows which mode is active.
  • On most desktop keyboards, the Number Lock key sits at the top left of the number pad and has a dedicated light next to it.
  • On laptops, Number Lock is usually accessed by holding Fn and pressing a key marked with a lock icon or the number pad symbol.
  • If your keyboard has no dedicated Number Lock key, you can turn it on or off through your computer's settings or on-screen keyboard.
  • Number Lock state often resets when you restart your computer, so you may need to turn it back on regularly.

Finding Number Lock on a desktop keyboard

On a standard desktop keyboard, the Number Lock key sits at the top left corner of the number pad — the block of keys on the right side of the keyboard. It is usually labeled "Num Lock" or "Num Lk" and often has a small light bulb or LED indicator next to it or above it. When you press the key once, the light turns on and the number pad types numbers. Press it again and the light turns off, switching the pad to cursor control.

The number pad itself is arranged like a phone keypad: numbers 1 through 9 in a grid, 0 at the bottom, and mathematical symbols around the edges. When Number Lock is off, those same keys become arrow keys (up, down, left, right), Page Up, Page Down, Home, and End. You will see these alternate functions printed in smaller text on the keys themselves.

If your keyboard is wireless or has a battery, make sure it is powered on before you try to toggle Number Lock. A dead battery will prevent the key from responding, and the light will not illuminate even if you press the key repeatedly.

Toggling Number Lock on a laptop keyboard

Laptop keyboards do not have a separate number pad, so they handle Number Lock differently. Most laptops use the Fn key — a modifier key usually located in the bottom left corner near Ctrl — combined with another key to toggle Number Lock. The partner key is usually marked with a lock icon, a number pad symbol, or the letters "Num Lk".

To turn Number Lock on or off, hold down Fn and press the key marked with the lock or number pad symbol. On many laptops this is the key labeled "Scroll Lock" or a key in the top row. You may not see a visual light on the keyboard itself, but your laptop will show a notification on screen confirming the change, or you can check the keyboard settings in your system preferences.

If you cannot find the Number Lock key on your laptop, check your keyboard's manual or search your laptop model name plus "Number Lock key" online. Different manufacturers place it in different locations, and some gaming or specialized keyboards have custom layouts that move the key to an unexpected spot.

Using an external keyboard with a laptop

If you have plugged an external desktop keyboard into your laptop, use the Number Lock key on that external keyboard — not the Fn combination on your laptop. The external keyboard's Number Lock key will work independently and control only that keyboard's number pad. Your laptop's internal keyboard is unaffected.

This is useful if you do a lot of number entry. You can leave Number Lock on on your external keyboard while keeping your laptop's internal keyboard in cursor mode. Just remember that when you unplug the external keyboard and go back to typing on the laptop alone, you will need to use the Fn combination again if you want to use the number pad.

Checking Number Lock status in your operating system

If you are unsure whether Number Lock is on or off, you can check your computer's settings. On Windows, open Settings, go to Ease of Access, then Keyboard. You will see a toggle for "Sticky Keys" and related options; some versions also show Number Lock status here. On Mac, open System Preferences, go to Keyboard, and look for Input Sources or Keyboard settings — though Mac does not use Number Lock the same way Windows does, so the option may not appear.

You can also use your computer's on-screen keyboard to toggle Number Lock without touching your physical keyboard. On Windows, search for "On-Screen Keyboard" in the Start menu and open it. A virtual keyboard will appear on your screen with a "Num Lk" button you can click. On Mac, search for "Keyboard Viewer" in Spotlight and open it to see your keyboard layout, though the on-screen keyboard is mainly for viewing rather than typing.

Why Number Lock keeps turning off

Number Lock often resets when you restart your computer or when your keyboard loses power. This is normal behavior — most keyboards do not remember the Number Lock state between sessions. If you use the number pad frequently, you may find yourself turning Number Lock back on every time you start work.

Some keyboards and computers allow you to set Number Lock to stay on by default. On Windows, you can change this in Settings under Ease of Access > Keyboard > Sticky Keys, though the option is not always available depending on your keyboard model. Check your keyboard's manual to see if it has a hardware switch or setting to lock Number Lock in the on position.

If Number Lock turns off unexpectedly while you are working — not just after a restart — your keyboard may have a loose connection or a software conflict. Try unplugging and replugging the keyboard, or restarting your computer. If the problem continues, the Number Lock key itself may be stuck or failing.

Troubleshooting when Number Lock will not respond

If you press the Number Lock key and nothing happens, start by checking whether your keyboard is powered on. Wireless keyboards need a working battery, and some keyboards have an on-off switch on the back or bottom. Press the key several times in case it is stuck.

Next, try restarting your computer. Number Lock is controlled partly by your operating system, and a restart often resets any stuck state. If you are using a wireless keyboard, also try moving it closer to your computer or removing any obstacles between the keyboard and the receiver.

If Number Lock still will not toggle, try using the on-screen keyboard method described above to turn it on or off. If the on-screen keyboard works but your physical keyboard does not, the Number Lock key itself may be broken and you may need to replace the keyboard. If neither method works, the issue may be in your operating system, and you should restart in Safe Mode or contact your computer's support team.

Frequently Asked Questions

Does every keyboard have a Number Lock key?

No. Compact keyboards, laptop keyboards without a number pad, and some gaming keyboards omit the Number Lock key entirely. If your keyboard has no number pad, it does not have a Number Lock key. You can still toggle Number Lock through your computer's settings or on-screen keyboard if you need to.

What is the difference between Number Lock and Caps Lock?

Caps Lock makes letters uppercase; Number Lock switches the number pad between numbers and cursor control. They are separate keys and do not affect each other. Caps Lock is usually in the left column of your main keyboard, while Number Lock is at the top of the number pad on the right.

Can I use the number pad when Number Lock is off?

Yes, but the keys will move your cursor instead of typing numbers. When Number Lock is off, the number pad functions as arrow keys and navigation buttons. If you need to type numbers, turn Number Lock on first.

Why does my keyboard light up when I press Number Lock but the pad still does not type numbers?

The light and the actual Number Lock function can sometimes become out of sync, especially on older keyboards or after a system crash. Try pressing Number Lock twice — once to turn it off, once to turn it back on. If that does not work, restart your computer and try again.

Do I need Number Lock on if I am using an external number pad?

Yes. External number pads, like external keyboards, also require Number Lock to be on in order to type numbers. The Number Lock key on your main keyboard controls the number pad function across all connected input devices.