Space · Mean-diameter reference · idealized sphere
Neptune diameter and size comparison
Neptune’s mean diameter is 49,244 kilometers in the JPL reference. Placing it beside Uranus makes their relatively small diameter difference visible at the same scale.
49244000 m
Sourced measurement- Measurement
- Mean diameter · twice JPL mean radius
- Subject or version
- Mean-diameter reference · idealized sphere
- In kilometers
- 49,244 km (1 km = 1,000 m)
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A little more perspective
The comparison doubles a mean radius of 24,622 kilometers, not the 24,764-kilometer equatorial radius. Its cloud illustration is interpretive, with no claim that the colors or storms reproduce a particular observation.
The displayed diameter is 2 × 24,622 km = 49,244 km. Doubling the source radius uncertainty gives ±38 km for diameter. The source defines mean radius through an equivalent-volume sphere. Its review date is not a new measurement date.
Quick facts
Neptune’s mean diameter is 49,244 kilometers in the JPL reference. Placing it beside Uranus makes their relatively small diameter difference visible at the same scale.
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.