About this calculator

Check two numeric general-rule conditions for a cargo article: minimum tiedown count and credited aggregate working load limit (WLL). The attachment path changes how much WLL is credited.

Inputs

How to use this calculator

Tiedown type

  1. Tiedowns of this typeWhole-device count for the selected attachment path.
  2. Marked working load limit (WLL) per tiedown (lb)Enter the verified assembly rating, limited by its lowest-rated component or anchor.
  3. Attachment pathThe path changes how its WLL is credited by the general federal rule.

Shared inputs

  1. Cargo article length (ft)Use the article length for the general tiedown-count rule.
  2. Cargo article weight (lb)Use the weight of the secured article or group.
  3. Blocked against forward movement?Select yes only when the article is blocked or immobilized against forward movement.

Enter the shipment or scenario values, then select Calculate result.

Method

Formula and variables

General rule: if blocked forward, minimum tiedowns = one per 10 ft or fraction. If not blocked: up to 5 ft and up to 1,100 lb needs 1; up to 5 ft and over 1,100 lb needs 2; over 5 through 10 ft needs 2; over 10 ft needs 2 plus 1 per additional 10 ft or fraction. Required aggregate WLL = cargo weight ÷ 2. Credit 1/2 WLL for vehicle-to-cargo and same-side paths; credit full WLL for a path crossing to the opposite vehicle side.

Tiedowns of this type
Whole-device count for the selected attachment path.
Marked working load limit (WLL) per tiedown (lb)
Enter the verified assembly rating, limited by its lowest-rated component or anchor.
Attachment path
The path changes how its WLL is credited by the general federal rule.
Cargo article length (ft)
Use the article length for the general tiedown-count rule.
Cargo article weight (lb)
Use the weight of the secured article or group.
Blocked against forward movement?
Select yes only when the article is blocked or immobilized against forward movement.

Interpret the result

Both tiedown count and credited working load limit (WLL) must meet the general-rule thresholds. The result does not inspect assembly condition, blocking, anchor strength, commodity rules or the complete securement arrangement.

Outputs: Minimum tiedown count and credited aggregate working load limit

General cargo rule only. Commodity-specific rules, special-purpose vehicles, assembly condition, anchor ratings, tie-down angles, friction, blocking strength and state requirements are not inspected. The entered WLL must reflect the lowest-rated tiedown component/anchor. A numeric pass is not a legal or physical safety certification.

Worked example

Check the arithmetic

This example uses the starting values shown above. The arithmetic below is calculated independently of the interactive result.

Work through the calculation

  1. A blocked 12 ft article needs ceil(12 ÷ 10) = 2 tiedowns.
  2. Required aggregate WLL = 2,000 ÷ 2 = 1,000 lb.
  3. Two 500 lb opposite-side crossing tiedowns provide 2 × 500 = 1,000 lb full credit. Both numeric checks pass.

Compare the displayed result

Expected displayed result: Numeric general-rule screen passes

FAQs

Why can a tiedown receive only half of its marked working load limit (WLL) as credit?

The general-rule credit depends on the attachment path. Vehicle-to-cargo and same-side return paths receive half; an opposite-side crossing receives full credit in this model.

Sources

These references support the methods or rules used on this page. Check the version effective for your shipment date and any applicable carrier terms or item-specific provisions.

Example inputs and options

Starting values are examples unless a field identifies a dated rule. Unit selectors convert only fields marked for conversion. Rates and model options keep the units and basis shown in their labels.

Tiedowns of this type
Example: 2
Marked working load limit (WLL) per tiedown (lb)
Example: 500
Attachment path
Example: Crosses to opposite vehicle sideOptions: Vehicle-to-cargo attachment; Returns to same side; Crosses to opposite vehicle side
Cargo article length (ft)
Example: 12
Cargo article weight (lb)
Example: 2000
Blocked against forward movement?
Example: YesOptions: No; Yes