Don't do that — use a single long cord instead.

Plug-to-plug adapters (male-to-male or female-to-female) are dangerous and often illegal. They create exposed live prongs and can cause arcing or fire. You’re asking about voltage drop, which is real, but the safety issue comes first.

Voltage drop happens when the total length of wire is too long for the gauge and load. Joining two cords with a proper male-female connection (one cord’s male end into the other’s female end) is fine — that’s how extension cords are designed. But using a plug-to-plug adapter introduces a hazardous connection point.

If you need more length, buy a single cord rated for the distance and amperage. Or use a heavier gauge (lower AWG number) for longer runs. Voltage drop is a function of total wire resistance, not how you connect them — assuming the connections are safe and tight.

In short: A proper male-female join works. A plug-to-plug adapter is a shortcut you shouldn’t take.