Mathematical Reference • Complete Formula Guide

Master Reference of All Cone Formulas

A definitive mathematical index of formulas for right circular cones, conical frustums, oblique cones, hollow shells, and surface area. Each formula includes variable definitions, mathematical explanations, and direct links to our dedicated calculators.

1. Standard Cone Volume (Radius & Height)

$$V = \frac{1}{3}\pi r^2 h$$

The fundamental formula for the volume of a right circular cone given base radius $r$ and vertical altitude $h$.

Open Radius Calculator →

2. Cone Volume from Diameter

$$V = \frac{1}{12}\pi d^2 h \approx 0.2618 \cdot d^2 h$$

Direct volume formula using base diameter $d = 2r$. Eliminates rounding errors from preliminary division.

Open Diameter Calculator →

3. Cone Volume from Slant Height

$$V = \frac{1}{3}\pi r^2 \sqrt{l^2 - r^2}$$

Solves volume when slant height $l$ is measured instead of vertical height, substituting $h = \sqrt{l^2 - r^2}$.

Open Slant Height Calculator →

4. Cone Volume from Circumference

$$V = \frac{C^2 h}{12\pi}$$

Calculates volume when base perimeter $C = 2\pi r$ is measured with a flexible tape measure ($r = C / 2\pi$).

Open Circumference Calculator →

5. Cone Volume from Base Area

$$V = \frac{1}{3} B h$$

Universal formula for any cone or pyramid when the cross-sectional base area $B$ and perpendicular height $h$ are known.

Open Base Area Calculator →

6. Slant Height Formula (Pythagorean)

$$l = \sqrt{r^2 + h^2}$$

Determines the generatrix length from the apex to the circular edge using right-triangle geometry.

Open Slant Solver →

7. Lateral Surface Area (Curved Face)

$$A_{lat} = \pi r l = \pi r \sqrt{r^2 + h^2}$$

The surface area of the cone's sloped walls excluding the circular bottom base.

Open Surface Area Calculator →

8. Total Surface Area

$$A_{tot} = \pi r^2 + \pi r l = \pi r(r + l)$$

Combined area of the circular base ($B = \pi r^2$) plus the curved lateral mantle ($A_{lat} = \pi r l$).

Open Surface Area Calculator →

9. Truncated Cone (Frustum Volume)

$$V = \frac{1}{3}\pi h (R^2 + r^2 + Rr)$$

Volume of a truncated cone with bottom radius $R$, top radius $r$, and vertical height $h$. Essential for hoppers and lampshades.

Open Frustum Calculator →

10. Oblique Cone Volume

$$V = \frac{1}{3}\pi r^2 h$$

By Cavalieri's principle, an oblique (tilted) cone has the exact same volume as a right cone of identical base and vertical height $h$.

Open Oblique Calculator →

11. Elliptical Cone Volume

$$V = \frac{1}{3}\pi a b h$$

Volume of an oval/elliptical cone where base semi-major axis is $a$ and semi-minor axis is $b$ (Base Area $B = \pi a b$).

Open Elliptical Calculator →

12. Hollow Cone Volume (Casing)

$$V = \frac{1}{3}\pi h (R^2 - r^2)$$

The solid material volume of a conical shell with outer radius $R$, inner radius $r$, and height $h$.

Open Hollow Cone Calculator →

13. Double Cone Volume (Hourglass)

$$V = \frac{2}{3}\pi r^2 h$$

Two identical cones joined at their apex or bases ($2 \times \frac{1}{3}\pi r^2 h$).

Open Double Cone Calculator →

14. Cone with Vertex Angle ($\theta$)

$$V = \frac{1}{3}\pi r^3 \cot(\theta)$$

Computes volume using base radius $r$ and half-apex angle $\theta$, substituting $h = r \cot(\theta)$.

Open Angle Calculator →

Cone Formulas Cheat Sheet

Summary comparison of parameters, variables, and units.

Geometric Quantity Standard Formula Known Parameters Standard Units Dedicated Tool
Volume ($V$) $V = \frac{1}{3}\pi r^2 h$ Radius $r$, Height $h$ cm³, m³, in³, L Volume Solver
Volume from Diameter $V = \frac{1}{12}\pi d^2 h$ Diameter $d$, Height $h$ cm³, m³, gal Diameter Solver
Slant Height ($l$) $l = \sqrt{r^2 + h^2}$ Radius $r$, Height $h$ cm, m, in, ft Slant Solver
Lateral Surface Area $A_{lat} = \pi r l$ Radius $r$, Slant $l$ cm², m², in² Area Solver
Total Surface Area $A = \pi r(r + l)$ Radius $r$, Slant $l$ cm², m², ft² Area Solver
Frustum Volume $V = \frac{1}{3}\pi h(R^2 + r^2 + Rr)$ $R, r, h$ cm³, m³, L, gal Frustum Solver