Flange Size Calculator

Look up common flange outer diameter, bolt-hole count, hole diameter and bolt-circle diameter by standard, DN and pressure class.

998.5K uses Updated · 2026-05-25 Runs locally · zero upload
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How to Use Flange Size Calculator

The Flange Size Calculator looks up common flange dimensions from standard, nominal diameter and pressure class. Choose ANSI or DIN, select DN and pressure class, then read outer diameter, bolt-hole count, hole diameter and bolt-circle diameter.

Confirm the standard system before using the number. ANSI Class 150 and Class 300 can differ, and DIN PN10 and PN16 may vary for some sizes. Matching DN alone does not guarantee matching flange geometry.

Formula & Theory - Flange Size Calculator

Flange geometry is specified by standards rather than derived from one universal formula. The calculator performs a table lookup using standard, DN and pressure class as the key.

The embedded table is a compact front-end reference for common sizes. Final purchasing, fabrication and drilling should follow the governing standard, material requirements and facing type.

Flange dimensions = table lookup by:
standard + nominal diameter + pressure class

Returned dimensions:
outer diameter
bolt-hole count
bolt-hole diameter
bolt-circle diameter

Use Cases for Flange Size Calculator

Use it for field checks, pipe-layout drafts, BOM estimates, teaching examples and supplier pages. It quickly answers questions such as the OD and bolt pattern for a common DN and pressure class.

Frequently asked questions about Flange Size Calculator

Are the dimensions generated by formula?

No. Flange geometry is looked up from standard dimension tables.

Does Flange Size Calculator work offline after the page loads?

The calculation logic runs in the browser, so no server is needed for the calculation after the page loads.

Is my data stored?

No. The page does not send your inputs to a server.