PCB Drill Aspect Ratio Calculator
Compare connection depth and hole diameter, with an optional project limit and clearly stated diameter basis.
How to Use the Aspect Ratio Tool
- Choose the hole structure. Use full board thickness for a through hole, or the actual drilled layer span for a blind or buried connection.
- Enter depth and diameter. Choose units and use the drill diameter before plating. For a laser microvia, enter its specified opening diameter.
- Read the ratio. Optionally enter your project’s ratio limit to calculate a corresponding minimum diameter. Export the geometry for your fabrication discussion.
Calculate Drill Aspect Ratio
Live geometry · updates as you editConnection geometry
Depth-to-diameter ratio
A geometric screening result. It does not evaluate plating distribution, annular rings, registration or reliability.
CSV and summary include the hole structure, entered dimensions and any conversion.
Calculations stay in this browser page.
What the Ratio Means
Use the processed depth
Aspect ratio = connection depth ÷ specified diameter. A 1.6 mm drilled span with a 0.30 mm drill gives 5.33 : 1. A buried connection is assessed at its processed sub-board thickness, rather than automatically using the final board thickness.
For a laser microvia, this tool uses the opening diameter you enter. Record that basis because opening and bottom dimensions may differ. See our microvia manufacturing explanation.
Compare a project limit
Minimum diameter = depth ÷ maximum ratio. The tool also calculates the maximum depth for your entered diameter and ratio. These are inverse geometric relationships, not a check of hole-pad clearance or a production approval.
Diameter basis reference: production drill tool versus board thickness. Supplier-specific limits are not copied into this tool.
Connect hole geometry with the manufacturing route
FLJ manufactures blind and buried via constructions and laser build-ups. Share the drill table and stackup with this calculation so the drilling span, hole size and metallization can be considered together.
Quick Answers
Should I use finished hole size or drill tool size?
Use the production drill diameter when it is available. The finished-hole option only estimates a pre-plating diameter from an assumed copper wall; it does not replace confirmed tooling data.
Does a lower ratio guarantee a reliable via?
No. Material, hole condition, plating, land geometry, registration and the complete build remain relevant. An entered comparison limit only checks the geometric ratio.