Free tool

Load securement calculator

Enter one article's weight and length, your tiedown type and how it attaches. The calculator applies both federal tests, the tiedown count rule and the working load limit rule, and shows which one decides the minimum.

Updated October 2026 / Estimates only, not financial or legal advice

Article weight (lb)

Article length (ft)

Tiedown type (default WLL, 49 CFR 393.108)

WLL per tiedown (lb)

Use the WLL marked on your strap or chain

How each tiedown is attached

Over the cargo, to the opposite sidecounts 100% of WLLOver the cargo, back to the same sidecounts 50%From the trailer to a point on the cargocounts 50% per end section

Blocked at the front (headerboard, bulkhead or other cargo)Wheeled or tracked machinery

Example defaults, replace with your load. Nothing you type leaves your browser.

Minimum tiedowns

By count rule (393.110): 4
By WLL rule (393.106(d)): 2
WLL needed (half the weight): 4,500 lb
WLL counted per tiedown: 4,000 lb

The length rule decides this one; your tiedowns already carry more than half the weight. If this is a metal coil of 5,000 lb or more, 49 CFR 393.120 adds specific coil rules on top.

This article needs at least 4 tiedowns. We ask the weight, length and securement questions before you book, so loads like this never surprise you at the shipper.

What the result means

The big number is the minimum number of tiedowns for this article. Underneath, you see the two federal tests separately:

By count rule comes from the article's length and weight (49 CFR 393.110).
By WLL rule is how many of your tiedowns it takes to reach half the cargo weight in working load limit (393.106(d)).

The higher of the two is your minimum. If you tick machinery and the article weighs 10,000 lb or more, the calculator also applies the four-tiedown minimum in 393.130.

How it is calculated

Count rule, article not blocked at the front:

Article	Minimum
5 ft or shorter, 1,100 lb or lighter	1
5 ft or shorter, over 1,100 lb	2
Over 5 ft up to 10 ft	2
Over 10 ft	2 + 1 for each extra 10 ft or part of 10 ft

Blocked at the front: one tiedown per 10 ft of length or fraction.

WLL rule:

WLL needed = cargo weight / 2
WLL counted per tiedown = marked WLL x 100% if it goes over the cargo to the opposite side, or x 50% if it returns to the same side or attaches to the cargo
Tiedowns needed = WLL needed / WLL counted per tiedown, rounded up

EXAMPLE. A 22 ft steel beam, 9,000 lb, not blocked, with 4 in straps over the top to the opposite rail. Count rule: 2 for the first 10 ft + 2 for the next 12 ft = 4. WLL rule: 4,500 lb needed / 4,000 lb per strap = 2. Minimum: 4.

Assumptions and sources

Default WLL values come from the table in 49 CFR 393.108. Marked WLL on your gear takes priority.
A tiedown assembly is only as strong as its weakest part, including the winch or binder and the anchor point. Enter the lowest rating.
The calculator covers one article at a time and the general rules. Metal coils of 5,000 lb or more (393.120), dressed lumber, machinery and other commodities have extra rules.
Not legal advice. Check the current regulation text.

How to use it before accepting a load

Ask the broker for the weight and length of the heaviest and longest pieces, not just the total.
Run each piece through the calculator with the gear you carry.
Add up the tiedowns across the load and check you have enough straps, chains and edge protectors, with a few spares.
If it is a coil, machinery or bundled lumber, read the commodity section in our flatbed load securement guide.
If you do not have the gear, say so before you book.

Finding the right loads for your gear starts with the search filters covered in our flatbed load boards guide. Our flatbed dispatch desk asks these questions on every load before you say yes.

FAQ

Questions about this calculator

Which rule decides how many straps I need?

Both apply, and you need whichever number is higher. The count rule (49 CFR 393.110) sets a minimum based on length and weight. The WLL rule (393.106(d)) says the working load limits must add up to at least half the cargo weight. Short, heavy freight is usually decided by WLL; long, light freight by the count rule.

Can I use this for a whole load with many pieces?

Run it once per article. Each article needs its own minimum count, and the WLL rule applies to each article or group of articles secured together. For bundled lumber, coils and machinery, check the commodity rules too.

What WLL should I enter for my straps?

The WLL marked on the strap or chain. If it is not marked, the default table in 49 CFR 393.108 applies, which is what the tiedown menu fills in. Unmarked chain is treated as the lowest grade.

Does passing this calculator mean my load is legal?

Not by itself. It checks the minimum count and WLL for one article. You still need tiedowns in good condition, edge protection where straps could be cut, any commodity-specific method, and in-transit inspections. Treat it as a planning tool.

Sources

49 CFR 393.106, aggregate working load limit (eCFR) (checked Oct 21, 2026)
49 CFR 393.108, working load limits (eCFR) (checked Oct 21, 2026)
49 CFR 393.110, minimum number of tiedowns (eCFR) (checked Oct 21, 2026)
49 CFR 393.120, metal coils (eCFR) (checked Oct 21, 2026)
49 CFR 393.130, heavy vehicles, equipment and machinery (eCFR) (checked Oct 21, 2026)

Let us run the numbers on every load

Our dispatchers book flatbed, step deck and conestoga loads against your minimum rate. 6% of gross, 5% for 2+ trucks.

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