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Flange Weight Calculator

Pick the standard (ASME B16.5 or EN 1092-1), the rating (Class 150–2500 or PN 10–100), the nominal size and the flange type — the outside diameter and thickness auto-fill from the standard, and the weight is estimated instantly. Best for blind and plate flanges; weld-neck and slip-on run heavier because of the hub.

Estimated weight
11.6 kg
Total for 1: 11.6 kg
Ring/blank estimate — WN & SO are heavier (hub)
OD 240 · ID 114 · 30 mm

Results are indicative; confirm exact mill weights on your MTC. For pipe use the pipe weight calculator.

/ How it works

How to estimate flange weight

Treating a flange as a flat ring (a disc with a bore), the estimate is:

Weight (kg) = (π ÷ 4) × (OD² − bore²) × thickness × density ÷ 1,000,000,000

Select the flange type and Class above (the Class sets the standard ASME B16.5 dimensions for that size). This estimate is accurate for blind and plate flanges. Weld-neck and slip-on flanges weigh more because of the hub and raised face, so treat the result as a lower-bound estimate. For exact catalogue weights by type, class and size (ASME B16.5 / B16.47), see our flanges page or ask us.

/ FAQ

Common questions

What is flange class (rating) and how is it different from schedule?
A flange’s Class (150, 300, 600, 900, 1500, 2500) is its pressure–temperature rating to ASME B16.5 — the flange equivalent of a pipe’s schedule. Higher class means a thicker, heavier flange with more/larger bolts. Select the class above so the estimate is labelled correctly; for exact catalogue weights by class and size, send us your list.
How do you calculate flange weight?
Approximate the flange as a ring: (π ÷ 4) × (OD² − bore²) × thickness × density ÷ 1,000,000,000, with dimensions in mm. This suits blind/plate flanges; weld-neck and slip-on are heavier due to the hub.
Why is my weld-neck flange heavier than the calculator says?
Because a weld-neck (and slip-on) flange has a tapered hub and raised face that this flat-ring estimate ignores. Use the estimate as a minimum and request the catalogue weight for exact figures.
Do you provide exact flange weights?
Yes — we supply weld-neck, slip-on, blind, socket-weld, lap-joint, threaded and orifice flanges to ASME B16.5/B16.47 and EN 1092-1 with published weights by class and size. Send your list for exact weights and a quote.
What density should I use for a stainless flange?
About 8000 kg/m³ for 304/316 stainless, 7850 for carbon steel, 7800 for duplex. Select the grade above.
/ Related
Need the material, not just the weight?

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Send type (WN/SO/blind), class, size and quantity — flanges to ASME B16.5/B16.47 & EN 1092-1 with exact weights.

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