Which measurement is bigger?
The recorded diameter of Size 7 basketball is 3.61 times the recorded diameter of Tennis ball. The selected measurements are 24.2 cm and 6.7 cm, respectively.
| Object | Metric size | Imperial size | Dimension |
|---|---|---|---|
| Size 7 basketball | 24.2 cm | 9.52 in | diameter |
| Tennis ball | 6.7 cm | 2.64 in | diameter |
What this comparison measures
Compare two chosen diameters that fit their sports’ regulations. The basketball diameter is derived from a stated circumference, while the tennis ball uses a stated diameter directly.
Size 7 basketball: Diameter derived from a chosen 760 mm circumference within the FIBA size 7 range: circumference ÷ π.
Tennis ball: Chosen 67 mm diameter within the ITF Type 2 permitted range.
The drawings use the same physical scale, but are simplified illustrations. They show a selected linear dimension rather than mass, surface area or volume. The space between objects makes the comparison readable and does not represent a real-world separation.
Inspect the sources
Both measurement sources are linked below the interactive board. The individual Size 7 basketball entry and Tennis ball entry provide the selected conventions and related objects.
Change either selection to explore another pair. The full size comparison tool also lets you enter a personal height. To practise estimating rather than reading the answer first, try the daily five.