How long does sperm stay in your body?

I was wondering how long sperm stays in your body and if he ejaculate in me today and yesturday does them amount of sperm double up in me or what

Most times it stays in your body until you have a duche.

ok it can stay in you for a few days not when you duch dua dut it can stay in you for a few days iy moves so it can stay for about a week lol hope this helps o some comes out afteer duching dut thats all I got

It can stay alive in your body for 8 days, I think.

up to 72 hours it can live but usually no longer than 48 hours

P.S. if you have sex a couple of days before you ovulate then substain from sex during ovulation you can still get pregnant from the sperm that is still alive in the uterus, so when you count your days stop having sex about day 10 or 11 to be safe since ovulation is usually on day 14. This is only if you have a regular 28 day cycle, you need to count your own days and figure out your own ovulation schedule, you can usually tell you are ovulating by a rise in body temp or you will feel a slight pain on your left or right side.
Also, to answer your question about sperm doubling up in you most of the ejaculate leaks out but some will stay in your uterus until it works it's way out or is absorbed by the body so I guess in a way you would double up maybe just a little.

3-7 days.
although it varies depending on the conditions inside the girl, the fitness of the sperm and wether it's a boy or girl sperm.