Hawaii Revised Statutes Division 5. Crimes and Criminal Proceedings § 706-671

(1) When a defendant who is sentenced to imprisonment has previously been detained in any State or local correctional or other institution following the defendant's arrest for the crime for which sentence is imposed, such period of detention following the defendant's arrest shall be deducted from the minimum and maximum terms of such sentence. The officer having custody of the defendant shall furnish a certificate to the court at the time of sentence, showing the length of such detention of the defendant prior to sentence in any State or local correctional or other institution, and the certificate shall be annexed to the official records of the defendant's commitment.

(2) When a judgment of conviction or a sentence is vacated and a new sentence is thereafter imposed upon the defendant for the same crime, the period of detention and imprisonment theretofore served shall be deducted from the minimum and maximum terms of the new sentence. The officer having custody of the defendant shall furnish a certificate to the court at the time of sentence, showing the period of imprisonment served under the original sentence, and the certificate shall be annexed to the official records of the defendant's new commitment.

(3) Notwithstanding subsection (1) and any other law to the contrary, when a defendant is sentenced for a crime committed while serving a sentence of imprisonment on a separate unrelated felony conviction, and the defendant was detained in any state or local correctional or other institution following the defendant's arrest for the crime for which a sentence is imposed, any periods of detention following the defendant's arrest that took place while the defendant was also serving a sentence of imprisonment for the separate unrelated felony conviction shall not be deducted from the minimum and maximum terms of the sentence imposed on the later crime.