Missouri Truck Weight and Size Limits
Legal limits for a truck in Missouri without a permit: Interstate axle and gross weights, height, width, and semitrailer length, each with its official source.
Missouri limits at a glance
| Limit | Missouri | Source |
|---|---|---|
| Interstate gross weight | 80,000 lb | 23 CFR 658.17, Weight (eCFR) |
| Interstate single axle | 20,000 lb | 23 CFR 658.17, Weight (eCFR) |
| Interstate tandem axle | 34,000 lb | 23 CFR 658.17, Weight (eCFR) |
| Width (National Network) | 102 in | 23 CFR 658.15, Width (eCFR) |
| Height | 14 ft on the Interstate and designated routes; 13 ft 6 in on other highways | Mo. Rev. Stat. § 304.170.2 |
| Semitrailer length | 53 ft | Mo. Rev. Stat. § 304.170.5 |
| Grandfathered semitrailer length | 53 ft | 23 CFR part 658, Appendix B, Grandfathered Semitrailer Lengths (eCFR) |
Interstate weight limits
Federal law sets the Interstate limits at 20,000 lb on a single axle, 34,000 lb on a tandem, and 80,000 lb gross, with the bridge formula on every axle group (23 CFR 658.17). States may keep higher limits they had before the federal limits took effect ("grandfather rights").
Grandfathered: up to 120,000 lb (entering from Kansas) or 90,000 lb (entering from Oklahoma) on National Network routes within 20 miles of those borders.
FHWA on Missouri: Missouri has a grandfather provision under Federal law (23 CFR Part 658, Appendix C) to allow vehicles to operate up to 120,000 lbs. GVW when entering the State from Kansas and 90,000 lbs. GVW when entering from Oklahoma, including parts of the Interstate System. See the Routes section for a full description of the routes to which this grandfather provision applies.
Bridge formula check with Missouri limits
A 5-axle tractor-trailer is filled in. Change the spacings and weights to match your rig; the limits for single axles, tandems, and gross are Missouri's Interstate limits.
Your result
Missouri limits off the Interstate
FHWA's summary of Missouri law for trucks in regular operation (no permit), including non-Interstate highways. It reflects state law as of October 1, 2012; check the state for later changes.
- Single axle
- 20,000 lbs.
- Tandem axle
- 34,000 lbs.
- Tridem axle
- Per State weight table
- Gross weight
- 80,000 lbs.
- Other
- 2,000 lbs. tolerance on non-Interstate highways / 12,000 lbs. steering axle
Where Missouri allows more than federal limits
- On highways other than the Interstate Highway System, vehicles may exceed single axle, tandem axle, and gross weight limitations by up to 2,000 lbs. However, total gross weight cannot exceed 80,000 lbs., except in the case of other specific exemptions.
- Missouri State statute allows for several axle and GVW exemptions for various types of vehicles and commodities.
- In commercial zones, the single axle load limit is increased up to 22,400 lbs.
Height, width, and length
- Width: 102 inches. States may not set a width limit of more or less than 102 inches on the National Network (23 CFR 658.15(a)). Permits can allow wider loads.
- Height: 14 ft on the Interstate and designated routes; 13 ft 6 in on other highways. There is no federal height limit; each state sets its own.
- Semitrailer length: 53 ft
- Grandfathered semitrailer length: 53 ft. The minimum semitrailer length the state must allow in a tractor-semitrailer combination on the National Network, based on lengths legal in the state on December 1, 1982. Federal law also requires at least 48 ft (23 CFR 658.13(b)(1)).
Over these limits you need a permit. Missouri oversize/overweight permits (888-737-0061).
Missouri compared with neighboring states
| State | Gross | Single | Tandem | Height | Semitrailer |
|---|---|---|---|---|---|
| Missouri | 80,000 lb | 20,000 lb | 34,000 lb | 14 ft on the Interstate and designated… | 53 ft |
| Arkansas | 80,000 lb | 20,000 lb | 34,000 lb | 14 ft | Pending |
| Illinois | 80,000 lb | 20,000 lb | 34,000 lb | Pending | Pending |
| Iowa | 80,000 lb | 20,000 lb | 34,000 lb | 13 ft 6 in | 53 ft in a truck tractor-semitrailer c… |
| Kansas | 80,000 lb | 20,000 lb | 34,000 lb | 14 ft | 59 ft 6 in |
| Kentucky | 80,000 lb | 20,000 lb | 34,000 lb | 13 ft 6 in on highways the Transportat… | 53 ft on designated highways |
Sources
Source: 23 CFR 658.17, Weight (eCFR) · Last verified Sep 28, 2026
Source: FHWA, Compilation of Existing State Truck Size and Weight Limit Laws (Report to Congress, May 2015), Appendix A: Missouri · Effective Oct 1, 2012 · Last verified Sep 28, 2026
Source: FHWA, Compilation of Existing State Truck Size and Weight Limit Laws (Report to Congress, May 2015), Appendix B: Summary of State Exceptions to Federal Truck Weight Limits · Effective Oct 1, 2012 · Last verified Sep 28, 2026
Source: 23 CFR 658.15, Width (eCFR) · Last verified Sep 28, 2026
Source: 23 CFR part 658, Appendix B, Grandfathered Semitrailer Lengths (eCFR) · Last verified Sep 28, 2026
Source: Mo. Rev. Stat. § 304.170.5 · Last verified Sep 28, 2026
Source: FHWA, Oversize/Overweight Load Permits: State permit contacts · Last verified Sep 28, 2026
Limits change, and cities, counties, and posted bridges can set lower ones. Check with Missouri before you run a load near the limits. Page data last verified Sep 28, 2026.