Does this calculator select an ASME gasket size?

No. Enter dimensions from the controlling drawing,manufacturer specification or licensed standard. The page does not reproduce B16.20,B16.21 or B16.5 tables.

Does gross annular area determine gasket seating load?

No. Gross geometric plan area is not the effective gasket area or a seating-load calculation. Joint design requires the applicable method,qualified gasket parameters and complete service/joint inputs.

Documented dimensions required — geometry only

Annular Gasket Geometry

Calculate nominal geometry from an identified gasket inner diameter,outer diameter and uncompressed thickness. No standard size,material or bolt load is inferred.

b=(Dₒ−Dᵢ)/2A=π(Dₒ²−Dᵢ²)/4mm or in

Nominal geometric results

Gross annular plan area

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Radial annulus width, b

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Mean diameter, G

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Inner circumference

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Outer circumference

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Mean circumference

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Radial-section rectangle, b·t

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Ideal solid-envelope volume, A·t

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Ideal annulus formulas

For documented inner diameter D_i,outer diameter D_o and uncompressed nominal thickness t,the radial width is b=(D_o−D_i)/2 and mean diameter is G=(D_o+D_i)/2. Subtracting the two circle areas gives the gross nominal plan area:

A = π(D_o²−D_i²)/4 = π·G·b

Inner,outer and mean circumferences are πD_i,πD_o and πG. The ideal rectangular radial section is b·t and the solid annular-envelope volume is A·t. For a spiral-wound,serrated,porous,composite or otherwise non-solid gasket,this envelope volume is not the actual constituent material volume or mass.

Not an effective seating area

A is only the area of the nominal planar annulus. It is not automatically the effective gasket reaction area and must not be multiplied by an assumed y value to claim seating load. Compression behaviour,flange facing,standard-specific effective width,service conditions,qualified gasket parameters and the full joint method determine design quantities.

Standards context — tables are not implemented

ASME B16.20—2023 is the current metallic-gasket edition identified by ASME and covers standardized metallic gasket constructions within its scope. ASME B16.21—2021 covers types,sizes,materials,dimensions,tolerances and markings for nonmetallic flat gaskets suitable for referenced flange standards. Their licensed dimensional tables are not reproduced or inferred here.

ASME B16.5—2025 covers ratings,materials,dimensions,tolerances,marking and testing for its specified flanges;flange bolting data must not be silently treated as a B16.20 gasket table. ASME PCC-1—2022 provides pressure-boundary bolted-joint assembly guidance within its scope;this elementary geometry is not a PCC-1 load calculation.

All selected-unit dimensions remain in that unit. NIST defines1in exactly as25.4mm,so area scales by25.4² and volume by25.4³ between equivalent inch/mm inputs. Sources checked12July2026. No closed clause,table,standard size,m/y factor or material limit is asserted.

Selection warning: verify flange standard/edition,NPS,class,facing,gasket construction,dimensions,tolerances,materials,marking,manufacturer data,fluid,temperature,pressure and applicable law. A geometric match alone does not establish suitability.