Space · Mean-diameter reference · idealized sphere
Moon diameter and size comparison
The Moon has a mean diameter of 3,474.8 kilometers in this reference. Its disk is about 27 percent of Earth’s mean diameter, even though photographs can make either object fill the frame.
3474800 m
Sourced measurement- Measurement
- Mean diameter · twice JPL mean radius
- Subject or version
- Mean-diameter reference · idealized sphere
- In kilometers
- 3,474.8 km (1 km = 1,000 m)
Add more subjects or change the units in the playground.
A little more perspective
This value is twice JPL’s 1,737.4-kilometer mean radius. Craters and mountains vary around the reference sphere, so the number is neither the width of one lunar photograph nor a maximum mountain-to-mountain distance.
The displayed diameter is 2 × 1,737.4 km = 3,474.8 km. Doubling the source radius uncertainty gives ±0.2 km for diameter. The source defines mean radius through an equivalent-volume sphere. Its review date is not a new measurement date.
Quick facts
The Moon has a mean diameter of 3,474.8 kilometers in this reference. Its disk is about 27 percent of Earth’s mean diameter, even though photographs can make either object fill the frame.
For a presentation or a research note, include the subject, the measurement definition, and the measurement used. A picture alone cannot explain those choices. The comparison guide explains how to export an image and its source notes together.
Sources and measurement notes
Source review recorded . Maintained by Ishan Karunaratne. Suggest a correction with a source and the exact measurement being compared.