How much interest on late payment

Dear you have to pay interest @ 18% for 4 days i.e. from 1st april to 4th april and for accounting code kindly see on below link.

https://www.servicetax.gov.in/circular/st-circular12/st-circ-165-2012-annx.pdf

Dear calculate interest @ 18% on service tax which you have paid on 4th april

in case your turnover is below 60 lakh, interest rate reduced by 3% so effective rate is 15%. in payment beyond 6 month interest at 24%(21%) and beyond 1 yr rate is 30%(27%).

For example due date is 31.03.2015 and service tax is paid on 30.04.2016, for the period 01.04.15 to 30.09.15 rate is 18%, 01.10.15 to 31.03.16 rate is 24% and from 01.04.16 to 30.04.16 rate is 30% ( for turnover less than 60 lakh, reduce 3%)