# Triangular Prism Calculator

Calculate the volume and surface area of a triangular prism. Enter triangle base, height, and prism length for instant results. Free online calculator.

## What this calculates

Find the volume and surface area of any triangular prism. Enter the base triangle dimensions and prism length to get the volume, total surface area, lateral surface area, and base area.

## Inputs

- **Triangle Base (b)** — min 0 — The base length of the triangular cross-section.
- **Triangle Height (h_t)** — min 0 — The height of the triangular cross-section (perpendicular to the base).
- **Prism Length (l)** — min 0 — The length (depth) of the prism connecting the two triangular faces.
- **Triangle Side A** — min 0 — One of the other sides of the triangular face. Leave blank to estimate from base and height.
- **Triangle Side B** — min 0 — The remaining side of the triangular face. Leave blank to estimate from base and height.

## Outputs

- **Volume** — Volume of the prism: base area x length.
- **Total Surface Area** — Total area of all five faces.
- **Lateral Surface Area** — Area of the three rectangular side faces.
- **Triangular Base Area** — Area of one triangular face: (1/2) x base x height.

## Details

A triangular prism is a 3D shape with two identical triangular faces (bases) and three rectangular side faces. Think of a Toblerone box or a tent shape.

**Volume:**

V = base area x length = (1/2 x b x h_t) x l

The volume is simply the area of the triangular cross-section multiplied by how long the prism extends.

**Surface Area:**

The total surface area is the sum of:
- Two triangular bases: 2 x (1/2 x b x h_t)
- Three rectangular side faces: (side1 + side2 + base) x length

So the total is: SA = b x h_t + (side1 + side2 + b) x l

**When Side Lengths Are Unknown:**

If you only know the base and height of the triangle, this calculator estimates the other sides by assuming an isosceles triangle. For precise results, enter all three side lengths of the triangular face.

**Real-World Examples:**

Triangular prisms show up in roof structures, tents, Toblerone packaging, optical prisms, and architectural designs. Calculating their volume helps with material estimates, while surface area determines covering or painting costs.

## Frequently Asked Questions

**Q: What is the formula for the volume of a triangular prism?**

A: The volume of a triangular prism is V = (1/2) x base x triangle height x prism length. In other words, find the area of the triangular cross-section and multiply by the length of the prism. For a triangle with base 6 and height 4 in a prism of length 10, V = (1/2)(6)(4)(10) = 120.

**Q: How do I find the surface area of a triangular prism?**

A: Add the areas of all five faces: two triangular bases plus three rectangular sides. Total SA = 2 x (1/2 x b x h_t) + (s1 + s2 + b) x l, where s1 and s2 are the other two sides of the triangle and l is the prism length.

**Q: What if I do not know all the triangle side lengths?**

A: If you only know the base and height, you can estimate the other sides. For an isosceles triangle, each unknown side equals sqrt((b/2)² + h²). For more accurate results, measure or calculate the actual side lengths using the Pythagorean theorem or trigonometry.

**Q: What is the difference between a triangular prism and a triangular pyramid?**

A: A triangular prism has two parallel triangular bases connected by three rectangles, making five faces total. A triangular pyramid (tetrahedron) has four triangular faces and comes to a point. The prism has a uniform cross-section along its length, while the pyramid tapers to an apex.

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Source: https://vastcalc.com/calculators/math/triangular-prism
Category: Math
Last updated: 2026-04-08