Iowa Truck Weight and Size Limits
Legal limits for a truck in Iowa without a permit: Interstate axle and gross weights, height, width, and semitrailer length, each with its official source.
Iowa limits at a glance
| Limit | Iowa | Source |
|---|---|---|
| Interstate gross weight | 80,000 lb | FHWA, Compilation of Existing State Truck Size and Weight Limit Laws (Report to Congress, May 2015), Appendices A and B |
| Interstate single axle | 20,000 lb | FHWA, Compilation of Existing State Truck Size and Weight Limit Laws (Report to Congress, May 2015), Appendices A and B |
| Interstate tandem axle | 34,000 lb | FHWA, Compilation of Existing State Truck Size and Weight Limit Laws (Report to Congress, May 2015), Appendices A and B |
| Width (National Network) | 102 in | 23 CFR 658.15, Width (eCFR) |
| Height | 13 ft 6 in | Iowa Code § 321.456 |
| Semitrailer length | 53 ft in a truck tractor-semitrailer combination | Iowa Code § 321.457(2)(f) |
| 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").
Iowa's 35,000 lb tandem is a state limit; FHWA's exceptions table lists no axle-weight exception for Iowa on the Interstate.
Longer combinations up to 129,000 lb (from South Dakota) or 95,000 lb (from Nebraska) may run on Interstate routes in Sioux City and its commercial zone.
FHWA on Iowa: Iowa has a grandfather provision under Federal law (23 CFR Part 658, Appendix C) to allow vehicles to operate up to 129,000 lbs. GVW on 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 Iowa 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 Iowa's Interstate limits.
Your result
Iowa limits off the Interstate
FHWA's summary of Iowa 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
- 35,000 lbs.
- Tridem axle
- Per State weight table
- Gross weight
- 80,000 lbs. on primary and non-primary highways / 90,000 lbs. on non-Interstate highways for six-axle vehicles / 96,000 lbs. on non-Interstate highways for seven-axle vehicles
- Other
- Five-axle livestock transports with a spread-axle semitrailer: 86,000; Six-axle: 90,000; Seven-axle: 96,000*
Where Iowa allows more than federal limits
- Six-axle vehicles on non-Interstate highways are allowed a gross vehicle weight of 90,000 lbs.
- Seven-axle vehicles on non-Interstate highways are allowed a gross vehicle weight of 96,000 lbs.
- Iowa State statute allows for several axle and GVW exemptions for various types of vehicles and commodities.
- Some agricultural vehicles are allowed higher single axle weights and GVWs on a seasonal basis.
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: 13 ft 6 in. There is no federal height limit; each state sets its own.
- Semitrailer length: 53 ft in a truck tractor-semitrailer combination
- 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. Iowa oversize/overweight permits (515-237-3268).
Iowa compared with neighboring states
| State | Gross | Single | Tandem | Height | Semitrailer |
|---|---|---|---|---|---|
| Iowa | 80,000 lb | 20,000 lb | 34,000 lb | 13 ft 6 in | 53 ft in a truck tractor-semitrailer c… |
| Illinois | 80,000 lb | 20,000 lb | 34,000 lb | Pending | Pending |
| Minnesota | 80,000 lb | 20,000 lb | 34,000 lb | 13 ft 6 in | 48 ft |
| Missouri | 80,000 lb | 20,000 lb | 34,000 lb | 14 ft on the Interstate and designated… | 53 ft |
| Nebraska | 80,000 lb | 20,000 lb | 34,000 lb | 14 ft 6 in | 53 ft including load |
| South Dakota | 80,000 lb | 20,000 lb | 34,000 lb | 14 ft | 53 ft on the Interstate and state trun… |
Sources
Source: FHWA, Compilation of Existing State Truck Size and Weight Limit Laws (Report to Congress, May 2015), Appendices A and B · 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 A: Iowa · 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: Iowa Code § 321.457(2)(f) · Last verified Sep 28, 2026
Source: Iowa Code § 321.456 · 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 Iowa before you run a load near the limits. Page data last verified Sep 28, 2026.