How long more are you going to work today? Don't you want to go home?

[tufguy]

Tom: How long more are you going to work today? Don't you want to go home?

Tim: Just a little more.I will work for fifteen more minutes.

Please check my sentences.

 

[probus]

Never use "How long more ...". It is unnatural. Correct is "How much longer ...".
And if the person intended to stop work earlier than usual the response would be "Not long" or 'Not much longer."

 

[Charlie Bernstein]

Yes. Or they might answer, "I'll be done soon."