New Hampshire DWI: First Offense

Last reviewed: 2026-07-17

A first DWI in New Hampshire is generally classified as a Class B misdemeanor (Class A / aggravated if 0.16+).

• Jail: none (aggravated: 17 days, 12 suspendable → 5 mandatory) – aggravated: 1 year; mandatory min none base; aggravated 0.16+ = 17 days (5 unsuspendable)
• Fine: $500–$2,000 ($500 + $120 penalty assessment (=$620) base; up to $2,000 aggravated)
• License suspension: 9 months – 2 years (18 months min aggravated); hardship: IID may be required; limited-driving 'reduction' possible after part of suspension
• Ignition interlock: Not required at this level — IID mandatory for aggravated (12–24 months after suspension) and repeat offenses.
• Alternative disposition: Impaired Driver Care Management Program (IDCMP) required before reinstatement; no charge dismissal.

Lookback period: 10 years. 10-year lookback for second-offense treatment; some enhancements reference lifetime priors. Subsequent (4th within lifetime after prior felony) can be a felony.