Wi-Fi is fast on my phone but slow on my laptop in the same room

Quick checks, assuming Windows 11:

1. Settings, Network & internet, Wi-Fi, then open the properties of the connected network (or the hardware properties) and look at the network band and the link speed.
2. Compare with the phone. Is the phone on 5 GHz and the laptop on 2.4?
3. Update the Wi-Fi driver from the laptop maker's support page, not from a driver updater tool.
4. Run the same test with the laptop standing next to the router.

Do those four before touching the router.

Set the 2.4 GHz channel width to 40 MHz, it doubles the speed. Everyone does this and it fixed my lag completely. Also set the channel by hand to 11 so the router never hops around.

@Raul M. the laptop is on the 2.4 band and the link speed is much lower than I expected. I will update the driver tonight and test beside the router tomorrow, then compare with the phone in the same spot.

@Tyler B. wider channels on 2.4 GHz are more exposed to interference and to your neighbours' networks. Speed tests can look good for a day and then stutter later. Leave 2.4 GHz at 20 MHz and let the 5 GHz band do the wide work.

In many laptops the Wi-Fi antennas sit around the lid, and I was surprised how much the screen angle changed my signal on a video call. I cannot say if that is your case, but try tilting the lid and moving the laptop a metre before you decide anything is broken.

At my hospital the break room microwave wrecked our 2.4 GHz Wi-Fi every lunchtime. At home I would check whether the slowness happens at particular times of day, in case something in the house is the cause.

@Marcus Hale thank you. I will leave the router settings alone until I have tested the laptop next to it, then compare the numbers with the phone from the sofa.