Cut Size vs Finished Size: What Tarp Dimensions Really Mean

Tarp dimensions are often misunderstood because the listed size does not always match the final measured size. This guide explains the difference between cut size and finished size, why tarps are typically smaller than their stated dimensions, and how to choose the correct size for your application.

What Is Cut Size?

Cut size refers to the dimensions of the tarp material before hems, seams, and grommets are installed. Manufacturers cut the tarp material slightly larger so that the edges can be folded, reinforced, and finished during production.

The cut size represents the original flat dimensions of the material prior to manufacturing finishing processes.

What Is Finished Size?

Finished size refers to the actual dimensions of the tarp after hems, seams, and grommets have been installed. During the finishing process, material is folded over to reinforce the edges, which reduces the overall dimensions.

As a result, the finished size of a tarp is typically smaller than its listed or cut size.

Why Are Tarps Smaller Than the Listed Size?

Most tarps are listed by their cut size rather than their finished size. Once hems and grommets are added, the finished tarp is commonly reduced by approximately 4 to 6 inches in each direction.

This size reduction is standard across the tarp industry and is not considered a defect. It allows manufacturers to reinforce the edges for strength and durability.

What Is an Acceptable Size Tolerance?

In addition to the reduction caused by hems, tarps may also have a size tolerance of up to approximately 3 percent from the stated dimensions. This tolerance accounts for material stretch, coating, and manufacturing variation.

Minor size differences within this tolerance range are considered normal and acceptable in tarp production.

Cut Size vs Finished Size Examples

For example, a tarp listed as 20 ft × 30 ft is measured before finishing. After hems and grommets are installed, the finished size may measure approximately 19 ft 6 in × 29 ft 6 in.

This reduction allows for reinforced edges and improved durability without compromising overall coverage.

How Finished Size Affects Fit

Finished size is especially important when tarps are used on frames, canopies, or structures. A standard or classic fit allows the tarp edge to sit slightly inside the frame rather than extending beyond it.

This prevents excessive stress on grommets and reduces the risk of tearing during wind or movement.

How to Choose the Correct Tarp Size

When selecting a tarp, always consider the finished size rather than relying solely on the listed dimensions. If full edge-to-edge coverage is required, sizing up may be recommended.

For frame applications, measuring the structure and accounting for peak height, slope, and attachment points helps ensure proper fit.

Quick Reference Summary

• Cut size is the tarp measurement before finishing
• Finished size is the actual measured size after hems and grommets
• Tarps are typically 4–6 inches smaller in each direction
• A size tolerance of up to 3 percent is normal
• Finished size affects fit and durability

For additional sizing guidance, explore our selection of tarps, heavy-duty tarps, and canopy covers, or review our frequently asked questions for common sizing concerns. Part of our Tarp & Canopy Buying Guides