Axle Weight Calculator
Input your scale ticket to check if your axles are within legal limits. Use the slide estimator to figure out how many holes to move your tandems or fifth wheel to fix an overweight axle.
Weight Status
Need to fix an overweight axle? Estimate how sliding your tandems or fifth wheel will shift the weight.
Legal
How to Use This Calculator
- 1
Enter Your Scale Ticket Data: Pull onto a CAT scale or any certified commercial scale and get your ticket. Enter the weights for your Steer Axle, Drive Axles, and Trailer Axles into the calculator.
- 2
Review Weight Status: The calculator instantly checks your weights against standard federal limits (12,000 lbs steer, 34,000 lbs drive, 34,000 lbs trailer, 80,000 lbs gross) and highlights any overages.
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Estimate Weight Shifts: If you are overweight on a specific axle, use the Slide Estimator. Select whether you want to slide your trailer tandems or fifth wheel, choose the direction, and input the number of holes.
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Verify Simulated Weights: Review the "Estimated Weights After Slide" section to see if your proposed adjustment brings all axles within legal limits before you actually pull the pins and move the truck.
What Is Axle Weight Distribution?
An axle weight calculator is an essential tool for professional truck drivers to ensure their loaded vehicle complies with Department of Transportation (DOT) weight regulations. While the total gross weight limit is typically 80,000 lbs, how that weight is distributed across the truck's axles is equally critical to avoid fines and infrastructure damage. For more tools related to load distribution, you can explore our load and weight calculators collection.
The standard federal limits for a typical 5-axle 18-wheeler are: 12,000 lbs on the steer axle, 34,000 lbs on the drive axles, and 34,000 lbs on the trailer tandem axles. If your load isn't perfectly balanced, you might be under your gross weight limit but over on a specific axle.
This is where our slide estimator comes into play. If your drive axles are too heavy, sliding your trailer tandems forward transfers weight to the trailer axles. Moving the fifth wheel changes the weight distribution between the steer and drive axles. Generally, moving trailer tandems shifts about 250 lbs per hole, while sliding a fifth wheel shifts about 500 lbs per hole.
By using this truck axle weight calculator, you can input your scale readings, simulate sliding your tandems, and know exactly how many holes you need to move to get legal—without having to guess and re-weigh multiple times. Managing your weight is just one aspect of trip planning; it's equally important to keep track of your driving time with our hours of service calculator to ensure full DOT compliance.
Weight Shift Reference Guide
When you are overweight on a specific axle but under the gross limit, sliding your axles is the standard way to fix it. Here is a quick reference guide on how sliding affects your weights.
| Adjustment Type | Direction Moved | Weight Shift Result | Avg. Lbs Per Hole |
|---|---|---|---|
| Trailer Tandems | Forward (Towards Cab) | Weight moves OFF Drive Axles ONTO Trailer Axles | ~ 250 lbs |
| Trailer Tandems | Backward (Towards Rear) | Weight moves OFF Trailer Axles ONTO Drive Axles | ~ 250 lbs |
| Fifth Wheel | Forward (Towards Cab) | Weight moves OFF Drive Axles ONTO Steer Axle | ~ 500 lbs |
| Fifth Wheel | Backward (Towards Rear) | Weight moves OFF Steer Axle ONTO Drive Axles | ~ 500 lbs |
Frequently Asked Questions
How much weight does sliding tandems shift per hole?
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On average, sliding trailer tandems shifts approximately 250 pounds per hole. Sliding the tandems forward (towards the cab) puts more weight on the trailer axles and takes weight off the drive axles. Sliding them backward does the reverse.
How much weight shifts when I slide the fifth wheel?
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Sliding the fifth wheel generally shifts about 500 pounds per hole. Sliding it forward transfers weight from the drive axles to the steer axle. Sliding it backward transfers weight from the steer axle to the drive axles.
What are the legal maximum axle weights?
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For a standard 5-axle semi-truck to reach the 80,000 lbs gross limit, the practical targets are typically 12,000 lbs (Steer), 34,000 lbs (Tandem Drive), and 34,000 lbs (Tandem Trailer). Note: Federal law technically allows up to 20,000 lbs on a single axle, but tire ratings and gross weight limits usually restrict steer axles to around 12,000 lbs. Specific bridge laws or state exceptions can also alter these limits.
How do I calculate my empty (tare) axle weights?
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The most accurate way is to weigh your truck empty at a CAT scale. A typical Class 8 tractor with an empty 53-foot trailer weighs around 35,000 lbs total, roughly distributed as 11,000 lbs on steer, 14,000 lbs on drives, and 10,000 lbs on trailer axles.
Can this calculator replace a real scale?
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No. This calculator is designed to estimate weight distribution adjustments based on standard rule-of-thumb measurements (250 lbs/hole for tandems, 500 lbs/hole for 5th wheel). You should always do a final re-weigh at a certified scale before hitting the highway if you were previously overweight.