About

Cylindrical concrete elements appear in columns, piers, well rings, sonotubes, and tank walls. A miscalculation of even 5% on diameter propagates to a 10% volume error because volume scales with r². Over-ordering concrete wastes budget; under-ordering halts a pour mid-placement, creating cold joints that compromise structural integrity. This calculator solves for both solid and hollow cylinders, adds optional base and top slabs, and converts the geometric result into mass and raw-material quantities using standard mix-design ratios from ACI 211.1 and IS 10262.

All inputs accept metric or imperial units. The tool assumes a homogeneous pour with no significant void content. For lightweight or aerated mixes, adjust the density preset accordingly. Rebar estimation is surface-area based and intended for preliminary budgeting only. Final reinforcement schedules require structural engineering review per ACI 318 or equivalent local code.

Formulas

The volume of a solid cylinder with outer radius R and height h:

V_solid = π × R² × h

For a hollow cylinder with wall thickness t, inner radius r = R − t:

V_wall = π × (R² − r²) × h

Optional base or top slab (solid disc for solid cylinder, ring for hollow):

V_disc = π × R² × t

V_ring = π × (R² − r²) × t

Total volume is the sum of wall, base, and top volumes. Concrete mass:

W = V_total × ρ

where R = outer radius, r = inner radius, h = height, t = wall thickness (also used as slab thickness for base/top), ρ = concrete density in kg/m³, and W = total weight in kg. Material quantities per cubic meter are derived from standard mix-design ratios for the selected concrete grade.

Reference Data

Concrete Grade	Cement kg	Sand kg	Gravel kg	Water L	Density kg/m³	Compressive Strength MPa	Typical Use
M100	220	870	1080	180	2350	7.5	Lean concrete, blinding
M150	260	855	1060	180	2355	10	Pathways, light foundations
M200	310	830	1040	185	2365	15	Residential foundations
M250	350	800	1020	185	2355	20	Beams, slabs, columns
M300	385	770	1000	190	2345	25	Structural columns, piers
M350	420	745	980	190	2335	30	Heavy-duty columns, tanks
M400	450	720	960	195	2325	35	Pre-stressed members
M450	480	700	940	195	2315	40	Industrial floors
M500	510	680	920	200	2310	45	Bridges, high-rise cores
Lightweight	350	600	500	210	1800	15	Insulating fills, blocks
Heavyweight	400	650	1400	175	2700	30	Radiation shielding

Frequently Asked Questions

Volume depends on the difference between the outer radius squared and the inner radius squared: V = π × (R² − r²) × h. Because both radii are squared, a small change in wall thickness t produces a disproportionately large change in volume. For example, increasing wall thickness from 100 mm to 120 mm on a 500 mm outer-radius cylinder increases wall volume by roughly 38%, not 20%. Always measure wall thickness with precision.

In construction, the outer form dimension is what you physically build or purchase (sonotube size, form ring size). The inner void is derived by subtracting wall thickness. This matches how contractors specify and order cylindrical formwork.

Yes. This calculator outputs the net geometric volume. Industry practice adds 5-10% for spillage, over-excavation, and form bulging. For pump delivery, add an extra 2-3% for line priming. Adjust the final number before ordering from a batch plant.

The ratios follow ACI 211.1 nominal mix proportions for each grade. Actual site mixes vary with aggregate moisture content, admixture use, and local aggregate grading. Use these quantities for budgeting and procurement. Final batch tickets come from your concrete supplier or a lab-designed mix.

Yes. Set the cylinder to hollow, enable a base slab, and disable the top. The concrete volume will be correct. However, the rebar estimate is approximate. Well rings per GOST 8020 or ASTM C478 have specific reinforcement cages; consult the relevant standard for exact bar counts and spacing.

M-grade (e.g., M300) historically denotes the target compressive strength in kg/cm² divided by approximately 10. M300 corresponds to roughly 25 MPa cube strength at 28 days. Modern codes use characteristic cylinder strength (f'c), which is about 80% of cube strength. The table in this tool lists both for cross-reference.