How Mercury’s apparent size changes
Mercury appears 8.3″ across on 23 October 2026. It is 0.809 AU from Earth and is increasing toward its next maximum of 10″ on 4 November 2026.
Mercury Size and Distance
Drag through the orbit to see how Mercury’s apparent size, distance, brightness and illumination change over time.
- Angular diameter
- 8.3″
- Distance to Earth
- 0.809 AU
- Magnitude
- 0.4
- Illuminated
- 34.7%
Drag the orbit to move through the cycle
Mercury Apparent Size Over Time
Approximately weekly samples cover the complete minimum–maximum–minimum cycle. Exact event dates are inserted between sampled rows.
| Date | Angular size | Distance | Magnitude | Rise–Set | Best observing |
|---|---|---|---|---|---|
| Minimum | 4.9″ | 1.378 AU | -1.2 | 05:13 – 17:52 | — |
| 5″ | 1.357 AU | -0.7 | 05:47 – 17:53 | — | |
| 5.1″ | 1.312 AU | -0.4 | 06:15 – 17:47 | — | |
| 5.4″ | 1.247 AU | -0.2 | 06:41 – 17:42 | — | |
| 5.8″ | 1.163 AU | -0.1 | 07:02 – 17:36 | — | |
| 6.4″ | 1.06 AU | 0 | 07:19 – 17:29 | — | |
| 7.2″ | 0.939 AU | 0.1 | 07:27 – 17:18 | — | |
| Today | 8.3″ | 0.809 AU | 0.4 | 07:17 – 17:00 | — |
| 9.6″ | 0.7 AU | 2 | 06:36 – 16:28 | — | |
| Maximum | 10″ | 0.673 AU | 6.2 | 05:45 – 15:58 | — |
| 9.9″ | 0.681 AU | 5.3 | 05:23 – 15:46 | — | |
| 8.5″ | 0.796 AU | 0.5 | 04:26 – 15:14 | 04:48 – 05:15 | |
| 6.9″ | 0.975 AU | -0.4 | 04:13 – 14:57 | 04:40 – 05:22 | |
| 5.9″ | 1.141 AU | -0.7 | 04:26 – 14:51 | 04:56 – 05:29 | |
| 5.3″ | 1.268 AU | -0.7 | 04:50 – 14:52 | 05:21 – 05:35 | |
| 5″ | 1.357 AU | -0.7 | 05:16 – 14:57 | — | |
| 4.8″ | 1.413 AU | -0.8 | 05:42 – 15:13 | — | |
| 4.7″ | 1.441 AU | -1 | 06:07 – 15:29 | — | |
| 4.7″ | 1.443 AU | -1.1 | 06:11 – 15:31 | — | |
Why Does Mercury Change Size?
Mercury’s physical diameter is not changing. Its apparent angular diameter changes mainly because the distance between Earth and Mercury changes as both planets move around the Sun.
When Will Mercury Have Its Largest Apparent Diameter?
Mercury will reach an apparent diameter of 10″ on 4 November 2026. That is about 1.2× wider than today, or roughly 1.5× the apparent disk area.
The largest apparent-size date is poorly placed or unobservable from your location. The largest sampled opportunity in this cycle is around 13 November 2026, when Mercury is about 8.5″ across and observable from 04:48 – 05:15.