Can I use nanometers or millimeters?

Yes. Use the same unit for every dimension; the numeric SA:V ratio will match that unit system.

Why does a smaller cell often have a higher SA:V?

As size increases, volume grows faster than surface area for many shapes.

Choose a shape, enter dimensions, and calculate surface area, volume, and SA:V.

Answer

0.6

SA:V ratio

Surface area: 314.1593 um^2

Volume: 523.5988 um^3

Volume per surface area: 1.6667

Exchange category: Low surface exchange

Shape

Radius (um)

Use the same length unit for all dimensions. Results are shown with um-style labels.

Examples

Result summary

Shape	Surface area	Volume	SA:V ratio
Sphere	314.1593 um^2	523.5988 um^3	0.6

SA:V = surface area / volume

The calculator computes surface area and volume from the selected shape, then divides surface area by volume.

Symbol	Variable	Description
SA	Surface area	The outside area available for exchange.
V	Volume	The internal volume of the shape.
SA:V	Ratio	Surface area per unit volume.

1
Choose a shape
Use sphere, cube, cylinder, rectangular prism, or custom values.
2
Enter dimensions
Keep all dimensions in the same length unit.
3
Read the ratio
Higher SA:V means more surface area per unit volume.

These formulas are used for the built-in shapes.

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