Cenvat credit on service tax

Any input service that relates to texable service is utilise for the payment of service tax.

Yes, Cenvat Credit is available on such services. But as there is some relaxation for providers of banking service, they generally do not issue serially numbered invoices. So it is always better to obtain a Certificate from bank with details of service tax charged and other basic details as required under Rule 4A of Service Tax Rules, 1994 and its proviso.

There is no formula for calculating Service Tax Credit. Whatever Service Tax appears as charged on invoices relating to input services can be used as Service Tax Credit. It is only when you are providing Taxable a.w.a. exempted services you need to take proportionate credit of input services.