Cargo securement working load limit calculator.

The rule in 393.106(d)

Section 393.106 of the Federal Motor Carrier Safety Regulations is the general requirement for securing articles of cargo. It applies to all types of cargo except commodities in bulk that lack structure or fixed shape, such as liquids, gases, grain and sand, when they are transported in a tank, hopper, box or similar device that forms part of the vehicle structure, and the commodity-specific rules in 393.116 through 393.136 take precedence where they add requirements. Paragraph (b) says cargo must be firmly immobilized or secured on or within the vehicle by structures of adequate strength, dunnage or dunnage bags, shoring bars, tiedowns or a combination. Paragraph (d), the part this calculator uses, says the aggregate working load limit of the tiedowns used to secure an article or group of articles against movement must be at least one-half times the weight of the article or group.

How each tiedown is counted

The regulation defines the aggregate working load limit as the sum of three kinds of contribution. One-half the working load limit of each tiedown that goes from an anchor point on the vehicle to an anchor point on the cargo. One-half the working load limit of each tiedown that is attached to an anchor point on the vehicle, passes through, over or around the cargo, and is then attached to an anchor point on the same side of the vehicle. And the full working load limit of each tiedown that goes from an anchor point on the vehicle, through, over or around the cargo, and then attaches to another anchor point on the other side of the vehicle. The three input groups in the form match those three cases.

What the working load limit of a tiedown is

Section 393.108(a) says the working load limit of a tiedown, associated connector or attachment mechanism is the lowest working load limit of any of its components, including the tensioner, or the working load limit of the anchor points it is attached to, whichever is less. You may use the manufacturer’s markings or the tables in 393.108, which apply when the material is not marked; where the manufacturer marks a value that differs from the tables, the marked value controls. Unmarked synthetic cordage is treated as polypropylene fiber rope, unmarked welded steel chain as grade 30 proof coil chain, and unmarked wire rope has a working load limit of one-fourth of its nominal strength. Enter the lowest figure in each tiedown assembly, including the anchor, not just the strap.

The separate minimum-number rule

Section 393.110 sets a minimum number of tiedowns in addition to the weight rule. If an article is not blocked against forward movement, it needs one tiedown if it is 5 feet or less long and 1,100 pounds or less; two if it is 5 feet or less and heavier than 1,100 pounds, or longer than 5 feet up to 10 feet; and for an article longer than 10 feet, two tiedowns plus one more for every 10 feet of length or fraction beyond the first 10. If an article is blocked, braced or immobilized against forward movement, it needs at least one tiedown for every 10 feet of length or fraction of it. The special-purpose vehicle exception in 393.110(d) covers machinery and fabricated structural items that must be fastened by special methods, and they must still be securely fastened. The optional length field above applies the first two rules.

Other performance criteria

The weight rule is only one test. Section 393.102 requires securement systems to hold under forces of 0.8 g forward, 0.5 g rearward and 0.5 g laterally without exceeding the breaking strength, and, for the working load limit, 0.435 g forward, 0.5 g rearward and 0.25 g laterally, applied separately. It also requires a downward force equivalent to at least 20 percent of the weight for cargo not fully contained by the vehicle structure, and it allows equivalent means such as immobilizing the cargo or carrying it in a sided vehicle with walls of adequate strength.

Worked example

A 10,000 lb load is held by four straps, each marked 5,400 lb, anchored on the vehicle and passing over the load to the same side. Each counts at half, 2,700 lb, so the aggregate is 10,800 lb. The requirement is 5,000 lb, so the rule is met with a 5,800 lb margin. If the same four straps ran over the load to the opposite side, each would count in full, 21,600 lb. If the load is 12 feet long and not blocked, 393.110(b)(3) requires at least three tiedowns, which four straps satisfy.

Limits of this page

This page applies only 393.106(d) and the length rule in 393.110. It does not apply the commodity-specific rules for logs, metal coils, heavy vehicles, concrete pipe and others in 393.116 to 393.136, the rules for tiedown equipment in 393.104, or state rules, and an inspector can cite you for securement failures even when this weight test passes. This is general information, not compliance advice; check the eCFR text and FMCSA guidance for your cargo.

Sources

Sources opened and read November 2, 2026.

• 49 CFR 393.106, General requirements for securing articles of cargo (eCFR, read November 2, 2026)
• 49 CFR 393.110, Additional requirements for determining the minimum number of tiedowns (eCFR, read November 2, 2026)
• 49 CFR 393.108, Determining the working load limit of a tiedown (eCFR, read November 2, 2026)
• 49 CFR 393.102, Minimum performance criteria for cargo securement devices and systems (eCFR, read November 2, 2026)