PCB analysis / Free calculator

Solder stencil aperture

Compare aperture area ratio, aspect ratio, and estimated deposited paste volume.

01 Your inputs

Aperture shape

Used for rectangular apertures only.

Calculated on your device. Inputs are not transmitted or stored.

02 Your result

Enter your values and select Calculate.

Inside a stencil aperture

Plan view · rectangular opening

Rectangular opening in stencil foilTeal shading marks opening area A. Gold edges mark its full perimeter P. l and w measure the clear rectangular opening. Shading identifies area, not solder paste.

Section through the opening

Foil thickness and exposed aperture wallsThe opening passes through the foil. Gold wall edges run through its full thickness t. The opening width matches the plan view. These walls continue around the entire perimeter.

Wall area is the full perimeter P multiplied by foil thickness t.

Opening area AAperture wallsStencil foil
l
Opening length
w
Opening width
t
Stencil foil thickness
Area ratio compares the opening area with the aperture wall area. The opening volume also depends on foil thickness; transfer efficiency adjusts the estimated deposited paste volume. Symbolic model; not to scale.

The method

Rarea=Aopeningperimeter×thickness

A worked example

For a 0.3 × 0.6 mm rectangle in a 0.1 mm stencil, area ratio = 1, aspect ratio = 3, nominal volume = 0.018 mm³, and paste volume at 80% transfer = 0.0144 mm³.

Assumptions & limits

Ideal rectangle or circle with vertical walls. Transfer efficiency is an input, not a prediction. Ratios are screening aids, not manufacturing approval. Confirm paste, finish, release, and process limits with the assembly supplier.

Calculation source: Extracted from PCBA Workbench v1.2.0; rectangle and circle reference cases tested.

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