Triangular Prism Volume Calculator
The volume of a triangular prism is V = ½ × base × height × length, which is the triangle's area times the prism's length. This triangular prism volume calculator works it out the moment you type the three numbers, and gives the answer in cubic inches or feet, liters, and gallons. A triangular prism, sometimes called a triangular based prism, has a triangle at each end and three rectangular sides, and the calculator shows the formula and steps with every result.
- Base × height × length
- Triangular based prism
- Base area shown
- 14 output units
- Faces, edges, vertices
Last updated June 15, 2026 Method: V = ½ b h L Reviewed by the Calcowa math team
Enter a positive base, height, and length to see the volume.
Show all units
V = ½ × 6 × 4 × 10 = 120 in³
What is a triangular prism?
A triangular prism is a solid with a triangle at each end and three flat rectangular sides joining them. It's also called a triangular based prism, and you'll spot one in a Toblerone bar, a camping tent, or the glass prism that splits light into a rainbow.
Its size comes down to three numbers you'll measure: the triangle's base and height, which set the cross-section, and the prism's length. Multiply the triangle's area by that length and you've got the volume.
How do you find the volume of a triangular prism?
To find the volume, work out the triangle's area, then multiply by the prism's length. Here's the full sequence:
- 1
Find the triangle areaMultiply half the base by the triangle height: ½ × b × h.
- 2
Measure the lengthMeasure the prism length, the distance between the two triangular ends.
- 3
MultiplyMultiply the triangle area by the length to get the volume.
- 4
Convert the unitsConvert to liters, gallons, or cubic feet if that's what you need.
Properties and net of a triangular prism
A triangular prism has 5 faces, 9 edges, and 6 vertices. The five faces are two triangles at the ends and three rectangles along the sides, the nine edges are where they meet, and the six vertices are the triangle corners. Unfold it flat and you've got its net: two triangles and three rectangles, the shape you'd cut from card to fold one up.
Triangular prism examples in real life
Once you know the shape, you'll see triangular prisms everywhere. A Toblerone chocolate bar is the classic one. So are a ridge tent, a glass prism that splits sunlight, the gable space under a pitched roof, a wedge-shaped doorstop, and a Tetra Pak carton. Each one keeps the same triangle cross-section all the way along its length, and that's exactly what makes the volume rule work.
Surface area and volume of a triangular prism
The volume fills the inside, but it's the surface area that wraps the outside. The volume is the triangle area times the length, ½ × b × h × L. The surface area adds the two triangular ends to the three rectangular sides, base × height + perimeter × length. This calculator shows the triangle's base area beside the volume, so you'll have both, and the triangular prism surface area calculator works out the full skin.
A triangular prism volume example
Say you've got a tent with a triangle 8 feet wide and 5 feet tall, and the tent runs 12 feet long. The triangle area is ½ × 8 × 5 = 20 square feet, and then you multiply by the length of 12.
V = ½ × 8 × 5 × 12 = 240 ft³
triangle area 20 ft² × length 12 ft
Type 8, 5, and 12 in feet above, and you'll get the matching liters and gallons without converting by hand.
Units and accuracy
Calcowa shows the triangular prism volume in liters, US and UK gallons, milliliters, fluid ounces, and cubic mm, cm, m, inches, feet, and yards all at once. Enter the triangle base, height, and prism length in any supported unit, and you'll get exact conversions, so the result suits packaging, camping, construction, and school work alike.
| Unit | Best for | Good to know |
|---|---|---|
| Cubic inches (in³) | Toblerone bars, wedges, small parts | Default when you enter inches |
| Cubic feet (ft³) | Tents, roof spaces, ramps | 1 ft³ = 1,728 in³ |
| Liters (L) | Containers and capacity | 1 L = 1,000 mL |
| US gallons (gal) | Troughs and tanks | 1 US gallon = 3.785 L |
| Cubic yards (yd³) | Soil wedges, large fills | 1 yd³ = 27 ft³ |
Frequently asked questions
Is a triangular based prism the same as a triangular prism?
Yes. Triangular based prism and triangular prism mean the same shape: a triangle at each end with three rectangular sides. The volume of either one is the triangle's area times the prism's length.
The volume of a triangular prism is V = ½ × base × height × length, which is the triangle's area times the prism's length. For a triangle 6 wide and 4 tall on a prism 10 long, that's ½ × 6 × 4 × 10 = 120 cubic units.
A triangular prism has 5 faces, 9 edges, and 6 vertices. The faces are two triangles at the ends and three rectangles around the sides, and the six vertices are the corners of the two triangles.
Yes. A triangular based prism is just a longer way of saying triangular prism: a solid with a triangle for its cross-section and a rectangle on each of its three sides. Both names mean the same shape.
A right triangular prism stands square, with its rectangular sides at right angles to the triangular ends. Most everyday prisms you'll meet are right prisms, and the volume rule, ½ × base × height × length, applies to all of them.
Work out ½ × base × height × length for the cubic volume, then read the litres or gallons line. The calculator shows litres, US and UK gallons, and millilitres next to the cubic result, so there's no manual conversion.
Triangular prisms show up as a Toblerone bar, a camping tent, a glass prism that splits light, the gable space under a pitched roof, and a wedge-shaped ramp. Anything that's got a triangle cross-section running straight is one.
Add the two triangular ends to the three rectangular sides: SA = base × height + perimeter × length. This calculator shows the base area next to the volume, and our triangular prism surface area tool covers the full skin.
Related calculators
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Cylinder volumeVolume of a round prism.
Need a prism volume fast?
Try the calculator above, or browse every shape in the geometry hub.