Cube volume formula: V = a³

The volume of a shape is how much 3D space it contains. For a cube, every edge has the same length, so the math becomes beautifully simple: multiply the side length by itself three times.

• a = side length (edge length)
• V = volume
• V = a × a × a = a³

A cube is a 3D version of a square. A square’s area is a² because you multiply length × width. Add a third dimension (height) and you multiply one more time: a × a × a. That third multiplication is why a cube’s volume grows fast when you increase the side length.

If the cube side is 5 cm, then: V = 5³ = 5 × 5 × 5 = 125 cm³. Since 1 cm³ = 1 mL, that’s also 125 mL (or 0.125 L). This is why cubic centimeters are common in medicine, lab work, and small container sizing.

If the side is 2 feet: V = 2³ = 8 ft³. Cubic feet are common in shipping, appliances (fridges), and storage boxes. If you’re comparing boxes, remember that a small increase in side length can create a big jump in volume.

Here’s the “viral” part people love screenshotting: volume explodes when you scale the side length. It’s not linear — it’s cubic.

• If you double the side length, volume becomes 2³ = 8× larger.
• If you triple the side length, volume becomes 3³ = 27× larger.
• If you increase the side by 10%, volume increases by about 1.1³ ≈ 1.331 → ~33%.

Conversions for volume are trickier than conversions for length because you must cube the conversion factor. For example, 1 m = 100 cm, but 1 m³ = (100 cm)³ = 1,000,000 cm³. That’s a million cubic centimeters in a cubic meter — which is also 1,000 liters. This is the #1 reason people get “off by a thousand” (or a million!) mistakes.

Step 1: we convert your side length into meters (a standard base). Step 2: we compute a³ to get cubic meters. Step 3: we convert back into your chosen unit (cm³, in³, ft³, etc.). Finally, we show a couple of helpful reference conversions (liters and cm³), since people often need them for real-world comparisons.

• DIY & building: estimating capacity, storage space, or simple volume checks.
• Shipping & packaging: comparing cube-shaped boxes and understanding dimension weight.
• School & homework: geometry, exponents, and unit practice.
• 3D printing / CAD: sanity checks on design dimensions and scaling effects.

If you only know one number (the side length), you can compute cube volume instantly. If you’re working with a rectangular box instead (different length/width/height), use a box/rectangular prism calculator — but for a cube, V = a³ is the fastest path.

Cube volume FAQs

• What is the volume of a cube?

  The volume of a cube is the amount of 3D space inside it. If the cube side length is a, the volume is V = a³. The unit will be “cubic” (cm³, m³, in³, ft³, etc.).

• Why does volume use cubic units (³)?

  Volume measures 3D space. Any conversion factor for length happens in three dimensions, so it’s cubed. That’s why 1 m³ is not 100 cm³ — it’s (100)³ = 1,000,000 cm³.

• How do I convert cm³ to liters?

  In metric, 1 cm³ = 1 mL and 1000 cm³ = 1 L. So if you get 2,500 cm³, that’s 2,500 mL = 2.5 L. This calculator shows liters automatically for metric conversions.

• How do I convert m³ to liters?

  1 m³ = 1000 L. So 0.2 m³ is 200 L. This is useful for tanks, aquariums, and bulk storage.

• Is a cube the same as a box?

  A cube is a special box (rectangular prism) where length = width = height. For a general box, volume is V = L × W × H. For a cube, that collapses to a × a × a.

• What if my “cube” edges aren’t perfectly equal?

  If the three dimensions are slightly different, use the rectangular box formula. For real‑world objects, “cube” often means “approximately cube‑shaped,” so measuring all three edges can be safer.

• Does doubling the side really make volume 8× bigger?

  Yes. Because (2a)³ = 8a³. That’s why small dimension changes matter a lot for volume, and why packaging “just one inch bigger” can dramatically change capacity.

• Can I use decimals?

  Absolutely. If a = 2.5 cm, then V = 2.5³ = 15.625 cm³. Choose rounding in the dropdown if you want fewer decimals.