Calculate open area percentage from open and total area, or for perforated sheet and wire mesh from hole size and pitch or mesh count and wire diameter.

Use square units for both areas, or select physical units for both.

Optional settings

Open Area Percentage Formula

OAP = OA / TA ร— 100

Variables:

  • OAP is the Open Area Percentage (%)
  • OA is the total open area
  • TA is the total overall area

To calculate the Open Area Percentage, divide the total open area by the positive total area in the same units, then multiply by 100. For perforated patterns, the fraction is C ร— (opening รท center pitch)ยฒ: C = ฯ€/(2โˆš3) for 60ยฐ staggered round holes, ฯ€/4 for straight round holes, and 1 for straight square holes. For uniform square wire mesh, the fraction is (1 โˆ’ mesh count ร— wire diameter in inches)ยฒ. These are ideal repeating-pattern formulas; the calculator also solves their inverses.

How to Calculate Open Area Percentage?

The following steps outline how to calculate the Open Area Percentage.

  1. First, determine the total open area. 
  2. Next, determine the total overall area. 
  3. Next, gather the formula from above: OAP = OA / TA * 100.
  4. Finally, calculate the Open Area Percentage.
  5. After inserting the variables and calculating the result, check your answer with the calculator above.

Example Problem : 

Use the following variables as an example problem to test your knowledge.

total open area = 160

total overall area = 800

FAQs

What is an Open Area Percentage?

Open Area Percentage (OAP) is a measure that indicates the ratio of the total open area to the total overall area, expressed as a percentage. It’s commonly used in various fields to assess the proportion of open or free space in a given area.

Why is calculating the Open Area Percentage important?

Open area describes geometry and can support comparisons of perforated sheets or wire mesh. It does not by itself establish airflow, pressure drop, strength or compliance. Repeating-pattern percentages exclude solid borders and partial edge openings; use measured open and overall panel areas when those must be included.

Can Open Area Percentage be applied to any type of area?

Yes, the concept of Open Area Percentage can be applied to any area where it’s important to quantify the ratio of open space to the total area. This includes architectural designs, agricultural fields, urban spaces, and industrial applications.

How can errors in calculating Open Area Percentage impact a project?

Errors in calculating the Open Area Percentage can lead to inadequate ventilation, poor space utilization, or non-compliance with regulatory standards. This can result in increased costs, delays in project timelines, and potential health and safety risks.