Tube Calculator
Calculate every geometric property of a tube or hollow cylinder: volume, surface area, circumference, and wall thickness. Choose from 8 input combinations.
Tube Formulas Reference Table
Tube geometry formulas relate all dimensions of a hollow cylinder. All calculations use pi = 3.14159265358979.
| Property | Symbol | Formula |
|---|---|---|
| Outer Circumference | C1 | C1 = 2 × π × r1 |
| Inner Circumference | C2 | C2 = 2 × π × r2 |
| Outer Surface Area | L1 | L1 = 2 × π × r1 × h |
| Inner Surface Area | L2 | L2 = 2 × π × r2 × h |
| End (Annular) Area | A | A = π × (r1² – r2²) |
| Volume Enclosed by C1 | V1 | V1 = π × r1² × h |
| Volume Enclosed by C2 | V2 | V2 = π × r2² × h |
| Volume of Solid Tube | V | V = π × (r1² – r2²) × h |
| Wall Thickness | t | t = r1 – r2 |
How to Use the Tube Calculator
The tube calculator requires exactly three known values to solve for all unknown properties of the hollow cylinder. Select the combination of known values from the dropdown, enter your measurements, and press Calculate.
Understanding the Tube Variables
A tube has two concentric circles in its cross section. The outer circle has radius r1 and circumference C1. The inner circle has radius r2 and circumference C2. The wall thickness t is the radial distance between the two circles. The height h is the length of the tube along its axis.
Volume vs Surface Area
The tube calculator returns two different volume values. V1 is the total volume enclosed within the outer wall, as if the tube were solid. V2 is the volume of the hollow core. V is the volume of material only (V1 minus V2), which is what you need to calculate the weight or cost of material.
Units and Scaling
All inputs must use the same unit of length. Select your unit from the dropdown for labeled output. Length outputs (r, C, h, t) use the selected unit. Area outputs use the unit squared. Volume outputs use the unit cubed. The calculator works identically regardless of which unit is chosen.
Tube Calculator Applications
Tube geometry calculations are used across engineering, construction, manufacturing, and everyday problem solving.
Plumbing and Piping
Plumbers and engineers use tube calculations to determine pipe capacity (internal volume flow), pipe weight (solid volume times material density), and insulation requirements (outer surface area). Specifying pipes by outer diameter plus wall thickness directly maps to the r1 and t inputs.
Structural Steel
Hollow structural sections (HSS) are specified by outer dimensions and wall thickness. Calculating the cross sectional area of a steel tube allows structural engineers to determine load capacity, weight per linear foot, and moment of inertia for beam design.
Manufacturing and Machining
CNC operators and machinists calculate tube volume to estimate material removal, determine workpiece weight, and compute cutting feeds. The annular end area is critical for face milling operations on hollow stock.