@Priyesh7 

Hi,

The typical rule of thumb is that you can achieve roughly half of the speed listed in the router's specification with a client device that supports the same wireless features like the router.

However, if the client device's wireless features are inferior to those of the router, then the achievable speed will be lower accordingly.

For example:
A router with a specified speed of "300 Mbps" in the 2.4 GHz band normally uses the 802.11n standard, has two Wi-Fi antennas and utilizes a channel width of 40 MHz. This would be good for a usable speed of about 150 Mbps, per the rule mentioned above.

However, if the client device (phone, tablet, TV, etc.) only has one Wi-Fi antenna, then the practical speed would be halved to about 75 Mbps.

Furthermore, if the client device doesn't support a channel width of 40 MHz, but only supports 20 MHz channel width, then the speed would be halved again to about 37 Mbps.

If the client device was a very old one that only supported the 802.11b standard, then the achievable speed would be even lower, perhaps something like 25 Mbps.