Surface Area of a Cone Calculator
🧊 Volume & surface area (3D). Use the Surface area of a cone formula to find surface area, radius, slant height: pick the value you want, type the others, and the answer updates as you go.
l = the slant height, √(r² + h²).
Pick the ○ next to the value you want to find, fill in the others, and it solves as you type.
What each letter means
| Quantity | Unit |
|---|---|
| Surface area | cm² |
| Radius | cm |
| Slant height | cm |
Worked example
Find the surface area when Radius = 5 cm, Slant height = 13 cm.
Using SA = π r² + π r l: Surface area = 282.74 cm².
Frequently asked questions
What is the formula for Surface area of a cone?
SA = π r² + π r l. l = the slant height, √(r² + h²).
What do the letters stand for, and what units are used?
Surface area in cm², Radius in cm, Slant height in cm.
How do you calculate surface area?
Put the values into SA = π r² + π r l. For example, with Radius = 5 cm, Slant height = 13 cm, surface area = 282.74 cm².
Can I solve for a different value?
Yes. In the calculator above, pick the circle next to any value (surface area, radius, slant height) and fill in the others: it rearranges the formula for you.
