Engineering calculator reviewed for preliminary design use · Last updated: March 2026
Estimate pressure-vessel cylindrical-shell thickness with t = P·R/(S·E − 0.6P) + CA, where R is shell inside radius. External pressure, openings, local loads, and fatigue are excluded.
What this calculator is used for
This calculator estimates pressure-required and corrosion-allowance-inclusive thickness
for a pressure vessel cylindrical shell under internal pressure. The dimensional input is
the shell inside radius R.
Typical engineering use cases
Preliminary plate-thickness studies for cylindrical vessel shells
Sensitivity checks for pressure, radius, allowable stress, and joint efficiency
Evaluation of corrosion allowance on total required thickness
Governing equation and methodology
The calculator implements this inside-radius relation:
t = P · R / (S · E − 0.6 · P) + CA
P is internal design pressure, R is shell inside radius, S is allowable stress,
E is weld joint efficiency, and CA is corrosion allowance. The denominator
S·E − 0.6P must be positive; this relation is not usable when that condition is not met.
Engineering assumptions and limitations
Internal pressure governs the design
Uniform material properties assumed
External loads (bending, thermal) not considered
Cylindrical shell geometry under internal pressure
Thin-shell applicability must be reviewed when thickness is not small relative to radius
Practical design notes
Pressure-required thickness and the CA-inclusive total are starting points, not the
selected nominal plate thickness. Select nominal plate after applying the negative
thickness tolerance specified by the plate material/procurement specification, forming
thinning, and fabrication minimums. The estimate does not evaluate external-pressure
buckling, openings and reinforcement, local loads, or fatigue.
Worked Example
Given:
Design pressure P = 1.0 MPa (internal)
Cylindrical shell inside radius R = 600 mm
Allowable stress S = 140 MPa, joint efficiency E = 1.00
Corrosion allowance CA = 3.0 mm
Method: Pressure thickness = P·R/(S·E − 0.6P) = 1.0·600/(140·1.00 − 0.6·1.0) = 4.304 mm. Total = 4.304 + 3.0.
Result: Pressure thickness = 4.30 mm; total thickness including CA = 7.30 mm.
Interpretation: These outputs match the calculator defaults and its inside-radius cylindrical-shell formula. The CA-inclusive result is a required minimum, not the selected nominal plate. Select nominal plate after applying the negative thickness tolerance specified for that plate material/procurement specification, forming thinning, and fabrication minimums. Also confirm S·E−0.6P > 0 and review thin-shell applicability; external pressure, openings, local loads, and fatigue are outside this estimate.
Common Mistakes & Misuse
Entering vessel diameter or outside radius where the formula requires the cylindrical shell inside radius R.
Adding corrosion allowance twice — the calculator already reports pressure thickness and then adds the entered CA.
Using operating pressure instead of the specified internal design pressure.
Treating the preliminary result as complete while omitting external pressure, openings, local loads, fatigue, or forming effects.
Frequently Asked Questions
Does this include corrosion allowance?
Yes. The calculator first evaluates pressure thickness as P·R/(S·E − 0.6P), then adds the entered corrosion allowance CA to report total thickness.
Is this the pipe wall thickness calculator?
No. This page uses the inside radius of a pressure-vessel cylindrical shell. Use the separate Pipe Wall Thickness Calculator for piping inputs and pipe-specific thickness selection.
When is the inside-radius shell equation applicable?
The denominator S·E − 0.6P must be positive. Also review whether the result remains a thin shell, with thickness small relative to radius. If either assumption is questionable, this preliminary relation is not an adequate model.
For preliminary estimation and educational use only. Results may depend strongly on assumptions, input data, fluid or material properties, and the range of validity of the underlying equation. Verify critical calculations independently and follow the applicable code, specification, and formal engineering review process before using any result for design, procurement, fabrication, operation, or safety decisions.