The short answer
Click the volume icon and check which output device is selected — Windows frequently keeps sending audio to the speakers, a monitor over HDMI, or a Bluetooth device that is still connected. Selecting headphones manually fixes the majority of cases.
A headphone jack that has genuinely failed is uncommon. What is common is audio being routed somewhere else while the headphones sit silent, and the operating system giving no indication that this has happened.
Check the routing first
Click the speaker icon in the taskbar and look at the device name above the volume slider. Click it to see every available output. A monitor connected by HDMI presents itself as an audio device and Windows often prefers it. A Bluetooth speaker left switched on in another room does the same.
On a Mac, System Settings, Sound, Output, and check the selected device.
Then work through the rest
Select the headphones as the output device
Click the volume icon, choose the headphone entry. If headphones do not appear at all even when plugged in, the machine is not detecting the jack, which points at the driver or the socket.
Clean the socket
Lint compacts in a headphone jack exactly as it does in a charging port, and it prevents the plug seating fully. With the laptop off, use a wooden toothpick gently, or a short burst of compressed air. This is a genuine and common cause.
Push the plug fully in and test another pair
A plug that is not seated produces sound in one ear only, or nothing. Test with headphones you know work, and test your headphones on a phone, so you know which side is at fault.
Check for a headset versus headphones mismatch
Combined jacks handle both, and the laptop sometimes decides a pair of headphones is a headset with a microphone, routing audio incorrectly. In the sound settings, look for a jack configuration option in the audio manager and set it manually.
Reinstall the audio driver
Device Manager, Sound video and game controllers, right-click the audio device, Uninstall device, then restart. Windows reinstalls it. If that fails, get the driver from the laptop manufacturer rather than a generic one — jack detection is handled by the manufacturer’s driver and the generic version often lacks it.
Run the audio troubleshooter
Settings, System, Troubleshoot, Other troubleshooters, Audio. It resets the audio stack and catches configuration faults you would otherwise hunt manually.
Disconnect Bluetooth audio devices
A paired speaker or headset that is still connected can silently capture the audio output. Turn Bluetooth off entirely as a test.
Plug the headphones in and rotate the plug slowly while audio plays. If sound cuts in and out as you turn it, the socket contacts are worn or dirty — a hardware fault, though often a cleanable one. If there is no sound in any position, the problem is more likely software routing.
Frequently asked questions
Why does sound come out of the speakers with headphones plugged in?
The laptop has not detected the jack insertion, usually a driver problem, or the output device is manually set to speakers. Reinstalling the manufacturer’s audio driver normally restores automatic switching.
Why do I only get sound in one ear?
Usually a plug not fully inserted, or debris in the socket. Also check the audio balance slider in sound settings, which mimics this exactly.
Can a headphone jack be repaired?
Yes, though on most laptops it is soldered to the motherboard or on a small daughterboard, so cost varies a lot by model. A USB audio adapter is a cheap and effective workaround.
Why does my microphone not work with a headset?
Combined jacks need the correct four-pole plug, and the laptop must be configured to treat the device as a headset. Check the jack configuration setting in the audio manager.
Check the output device selection before anything else. It is the answer far more often than a broken socket.
