New Hampshire Truck Weight Limits
Complete guide to commercial vehicle weight regulations in New Hampshire, including axle limits, permit requirements, and seasonal restrictions.
Weight Limits
| Axle Type | New Hampshire Limit | Federal Limit | Difference |
|---|---|---|---|
| Single Axle | 22,400 lbs | 20,000 lbs | +2,400 lbs |
| Tandem Axle | 36,000 lbs | 34,000 lbs | +2,000 lbs |
| Tridem Axle | 54,000 lbs | 0 lbs | |
| Gross Vehicle Weight | 80,000 lbs | 80,000 lbs | 0 lbs |
| Steer Axle (min) | 12,000 lbs | 12,000 lbs | 0 lbs |
| Steer Axle (max) | 22,400 lbs | 20,000 lbs | +2,400 lbs |
New Hampshire has source-verified table, spacing, route, permit, or vehicle-specific rules. The calculator applies verified base limits and implemented contexts, but exact special-case output still needs source-chart fixtures.
Showing interstate route, standard operation.
Enforcement tolerance: 5% on gross weight.
Bridge Formula
New Hampshire uses the standard Federal Bridge Formula to calculate maximum weight on groups of consecutive axles.
- W = Maximum weight (lbs)
- L = Distance between outer axles (ft)
- N = Number of axles in the group
Permissible Gross Loads in New Hampshire
| Permissible Gross Loads for Vehicles in New Hampshire | ||||||||
|---|---|---|---|---|---|---|---|---|
| Based on FederalBridge Formula: W = 500 × [LN/(N-1) + 12N + 36] | ||||||||
| Showing interstate route, standard operation | ||||||||
Distance (ft) L | 2 AXLES | 3 AXLES | 4 AXLES | 5 AXLES | 6 AXLES | 7 AXLES | 8 AXLES | 9 AXLES |
| 4 | 34,000 | — | — | — | — | — | — | — |
| 5 | 35,000 | — | — | — | — | — | — | — |
| 6 | 36,000 | — | — | — | — | — | — | — |
| 7 | 36,000 | — | — | — | — | — | — | — |
| 8 | 36,000 | 42,000 | — | — | — | — | — | — |
| 9 | 39,000 | 42,500 | — | — | — | — | — | — |
| 10 | 40,000 | 43,500 | — | — | — | — | — | — |
| 11 | 41,000 | 44,000 | — | — | — | — | — | — |
| 12 | 42,000 | 45,000 | 50,000 | — | — | — | — | — |
| 13 | 43,000 | 45,500 | 50,500 | — | — | — | — | — |
| 14 | 44,000 | 46,500 | 51,500 | — | — | — | — | 80,000 |
| 15 | 44,800 | 47,000 | 52,000 | — | — | — | — | 80,000 |
| 16 | 44,800 | 48,000 | 52,500 | 58,000 | — | — | — | 80,000 |
| 17 | 44,800 | 48,500 | 53,500 | 58,500 | — | — | — | 80,000 |
| 18 | 44,800 | 49,500 | 54,000 | 59,000 | — | — | — | 80,000 |
| 19 | 44,800 | 50,000 | 54,500 | 60,000 | — | — | — | 80,000 |
| 20 | 44,800 | 51,000 | 55,500 | 60,500 | 66,000 | — | — | 80,000 |
| 21 | 44,800 | 51,500 | 56,000 | 61,000 | 66,500 | — | — | 80,000 |
| 22 | 44,800 | 52,500 | 56,500 | 61,500 | 67,000 | — | — | 80,000 |
| 23 | 44,800 | 53,000 | 57,500 | 62,500 | 68,000 | — | — | 80,000 |
| 24 | 44,800 | 54,000 | 58,000 | 63,000 | 68,500 | 74,000 | — | 80,000 |
| 25 | 44,800 | 54,000 | 58,500 | 63,500 | 69,000 | 74,500 | 80,000 | 80,000 |
| 26 | 44,800 | 54,000 | 59,500 | 64,000 | 69,500 | 75,000 | 80,000 | 80,000 |
| 27 | 44,800 | 54,000 | 60,000 | 65,000 | 70,000 | 75,500 | 80,000 | 80,000 |
| 28 | 44,800 | 54,000 | 60,500 | 65,500 | 71,000 | 76,500 | 80,000 | 80,000 |
| 29 | 44,800 | 54,000 | 61,500 | 66,000 | 71,500 | 77,000 | 80,000 | 80,000 |
| 30 | 44,800 | 54,000 | 62,000 | 66,500 | 72,000 | 77,500 | 80,000 | 80,000 |
| 31 | 44,800 | 54,000 | 62,500 | 67,500 | 72,500 | 78,000 | 80,000 | 80,000 |
| 32 | 44,800 | 54,000 | 63,500 | 68,000 | 73,000 | 78,500 | 80,000 | 80,000 |
| 33 | 44,800 | 54,000 | 64,000 | 68,500 | 74,000 | 79,000 | 80,000 | 80,000 |
| 34 | 44,800 | 54,000 | 64,500 | 69,000 | 74,500 | 80,000 | 80,000 | 80,000 |
| 35 | 44,800 | 54,000 | 65,500 | 70,000 | 75,000 | 80,000 | 80,000 | 80,000 |
| 36 | 44,800 | 54,000 | 66,000 | 70,500 | 75,500 | 80,000 | 80,000 | 80,000 |
| 37 | 44,800 | 54,000 | 66,500 | 71,000 | 76,000 | 80,000 | 80,000 | 80,000 |
| 38 | 44,800 | 54,000 | 67,500 | 71,500 | 77,000 | 80,000 | 80,000 | 80,000 |
| 39 | 44,800 | 54,000 | 68,000 | 72,500 | 77,500 | 80,000 | 80,000 | 80,000 |
| 40 | 44,800 | 54,000 | 68,500 | 73,000 | 78,000 | 80,000 | 80,000 | 80,000 |
| 41 | 44,800 | 54,000 | 69,500 | 73,500 | 78,500 | 80,000 | 80,000 | 80,000 |
| 42 | 44,800 | 54,000 | 70,000 | 74,000 | 79,000 | 80,000 | 80,000 | 80,000 |
| 43 | 44,800 | 54,000 | 70,500 | 75,000 | 80,000 | 80,000 | 80,000 | 80,000 |
| 44 | 44,800 | 54,000 | 71,500 | 75,500 | 80,000 | 80,000 | 80,000 | 80,000 |
| 45 | 44,800 | 54,000 | 72,000 | 76,000 | 80,000 | 80,000 | 80,000 | 80,000 |
| 46 | 44,800 | 54,000 | 72,500 | 76,500 | 80,000 | 80,000 | 80,000 | 80,000 |
| 47 | 44,800 | 54,000 | 73,500 | 77,500 | 80,000 | 80,000 | 80,000 | 80,000 |
| 48 | 44,800 | 54,000 | 74,000 | 78,000 | 80,000 | 80,000 | 80,000 | 80,000 |
| 49 | 44,800 | 54,000 | 74,500 | 78,500 | 80,000 | 80,000 | 80,000 | 80,000 |
| 50 | 44,800 | 54,000 | 75,500 | 79,000 | 80,000 | 80,000 | 80,000 | 80,000 |
| 51 | 44,800 | 54,000 | 76,000 | 80,000 | 80,000 | 80,000 | 80,000 | 80,000 |
| 52 | 44,800 | 54,000 | 76,500 | 80,000 | 80,000 | 80,000 | 80,000 | 80,000 |
| 53 | 44,800 | 54,000 | 77,500 | 80,000 | 80,000 | 80,000 | 80,000 | 80,000 |
| 54 | 44,800 | 54,000 | 78,000 | 80,000 | 80,000 | 80,000 | 80,000 | 80,000 |
| 55 | 44,800 | 54,000 | 78,500 | 80,000 | 80,000 | 80,000 | 80,000 | 80,000 |
| 56 | 44,800 | 54,000 | 79,500 | 80,000 | 80,000 | 80,000 | 80,000 | 80,000 |
| 57 | 44,800 | 54,000 | 80,000 | 80,000 | 80,000 | 80,000 | 80,000 | 80,000 |
| 58 | 44,800 | 54,000 | 80,000 | 80,000 | 80,000 | 80,000 | 80,000 | 80,000 |
| 59 | 44,800 | 54,000 | 80,000 | 80,000 | 80,000 | 80,000 | 80,000 | 80,000 |
| 60 | 44,800 | 54,000 | 80,000 | 80,000 | 80,000 | 80,000 | 80,000 | 80,000 |
Values reflect FHWA policy of rounding down when calculated weights fall exactly halfway between 500-pound increments.
New Hampshire GVW limit of 80,000 lbs differs from the federal interstate limit of 80,000 lbs.
New Hampshire allows a 5% enforcement tolerance on gross weight.
New Hampshire has source-verified table, spacing, route, permit, or vehicle-specific rules. The calculator applies verified base limits and implemented contexts, but exact special-case output still needs source-chart fixtures.
Always verify current regulations with New Hampshire DOT before making shipping decisions.
Seasonal Weight Restrictions
Spring Weight Restrictions (Spring Posting)
62.5% weight reduction on posted_state_highways
Exemptions: home_heating_oil, processed_milk, maple_sap, septic_pumper
Permit Information
Requirements & Costs
- Overweight threshold
- 99,000 lbs
- Single trip permit
- $115
- Annual permit
- $115
- Processing time
- Online processing available
- Divisible loads
- Not permitted
- Online application
- Available
Required Documents
- Insurance
- Registration
Special Vehicle Provisions
special Haul Vehicles
Vehicles certified under RSA 266:18-d can operate at 99k lbs. Federal exemptions allow 99k lbs on I-89, I-93, I-95
GVW: 99,000 lbs
Contact Information
Permit Office
Hours: Mon-Fri 8:00 AM - 4:30 PM EST
Official Website
New Hampshire DOT WebsiteImportant Notes
- STANDARD LEGAL LIMIT: 99,000 lbs gross weight for certified vehicles (RSA 266:18-b)
- STANDARD LEGAL LIMIT: 22,400 lbs single axle for certified vehicles
- Federal exemption allows 99,000 lbs on I-89, I-93, I-95
- Spring posting reduces limits to 30,000 lbs on posted state highways
- Tolerance: 5% gross weight, 10% axle weights for certified vehicles
Calculate Your Weight Compliance
Use our interactive calculator to check if your truck configuration is compliant with New Hampshire regulations.
Open Weight CalculatorNeighboring States
Need Help With New Hampshire Compliance?
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Get Expert ConsultationSource: New Hampshire RSA 266:18-a, 266:18-b, 266:18-d | Last Updated: 1/13/2025 | Effective: 1/1/2025
Always verify current regulations with official sources before making shipping decisions.