N.H. Rev. Stat. Ann. § 651-A:23

Any prisoner who is confined to the state prison, any house of correction, any jail or any other place shall be granted credit against both the maximum and minimum terms of his sentence equal to the number of days during which the prisoner was confined in jail awaiting and during trial prior to the imposition of sentence and not under any sentence of confinement. The clerk of the court sentencing a prisoner shall record in the mittimus the number of days of such confinement, and the credit provided for herein shall be calculated on the basis of such information.