My assurance conver 80% , if I need a surgery of 4000$ how much do I need to give out of my pocket ?

If your insurance coverage is 80%, it means that the insurance will cover 80% of the surgery cost and you will be responsible for the remaining 20%.

To calculate the amount you need to pay out of pocket:
Out of pocket payment = 20% of $4000

Out of pocket payment = (20/100) * $4000
= $800

So, you would need to give $800 out of your pocket for the surgery.