Below is a list of the smallest exoplanets so far discovered, in terms of physical size, ordered by radius.
The sizes are listed in units of Earth radii . All planets listed are smaller than Earth and Venus, up to 0.7 Earth radii. The NASA Exoplanet Archive is used as the main data source.
| Exoplanet | Radius | Notes and references | |
|---|---|---|---|
| SDSS J1228+1040 b (SDSS J122859.92+104033.0 b, WD 1226+110 b) | 0.010[1] | Extrasolar planetesimal. Likely a remnant iron core. Radius is in the range of 1.2120 km. | |
| WD 1145+017 b | ~0.03 | Disintegrating planetesimal, likely one of several orbiting its star. Likely about one-tenth the mass of Ceres and ~200 km in radius. | |
| Ceres | 0.0742 | Shown for comparison | |
| Pluto | 0.1863 | Shown for comparison | |
| Moon | 0.2725 | Shown for comparison | |
| Kepler-37b | Smallest known exoplanet. | ||
| PSR B1257+12 b (Draugr) | ~0.338 | Least massive known exoplanet, at 0.02 Earth masses. Radius estimated from mass-radius relationship.[2] | |
| Kepler-1520b | ≲0.36 | Disintegrating planets with poorly known radii, all thought to be smaller than Mercury. | |
| KOI-2700b | |||
| K2-22b | |||
| Mercury | 0.3826 | Shown for comparison | |
| Kepler-444b | |||
| Ganymede | 0.413 | Shown for comparison | |
| Kepler-102b | |||
| Kepler-444c | |||
| Kepler-1971b (KOI-4777.01) | |||
| Kepler-1994b | [3] | ||
| Kepler-1308b | |||
| Kepler-444d | |||
| Mars | 0.5325 | Shown for comparison | |
| Kepler-62c | |||
| Kepler-444e | |||
| Gliese 238 b | |||
| Kepler-102c | |||
| Kepler-42d | |||
| Kepler-1583b | |||
| Kepler-1998b | [4] | ||
| Kepler-1087b | |||
| K2-89b | |||
| Kepler-1877b | 0.624 | ||
| K2-137b | |||
| Kepler-1371c | |||
| Kepler-138b | |||
| Kepler-1130d | 0.645 | ||
| Kepler-1351b | |||
| Kepler-1542c | |||
| Kepler-271d | |||
| Kepler-431c | 0.668 | ||
| Kepler-1558b | |||
| LHS 1678 b | |||
| K2-116b | |||
| Kepler-141b | |||
| K2-297b (EPIC 201497682 b) | |||
| Gliese 367 b (Tahay) | Smallest known exoplanet within 10 parsecs. | ||
| Kepler-378c |
Kepler-37e is listed with a radius of in the Exoplanet Archive based on KOI data, but the existence of this planet is doubtful, and assuming its existence, a 2023 study found a mass of, inconsistent with such a small radius.
KOI-6705.01, listed as a potential very small planet in the KOI dataset, was shown to be a false positive in 2016.
Below shows a list of Kepler and TESS candidates below that have yet to be confirmed.
| Kepler object of interest | Radius | Notes and references | |
|---|---|---|---|
| KOI-4582.01 | 0.35 | ||
| KOI-2298.03 | 0.36 | ||
| KIC 1718360.01 | 0.366[5] | ||
| KOI-2169.04 | 0.37 | ||
| KOI-7174.01 | 0.37 | ||
| KOI-8012.01 | 0.42 | ||
| KOI-6860.01 | 0.43 | ||
| KOI-2059.02 | 0.44 | ||
| KOI-304.02 | 0.46 | ||
| KOI-7793.01 | 0.46 | ||
| KOI-2678.02 | 0.48 | ||
| KOI-6631.01 | 0.48 | ||
| KOI-2421.02 | 0.48 | ||
| KOI-5974.01 | 0.49 | ||
| KOI-3444.03 | 0.5 | ||
| KOI-2295.01 | 0.52 | ||
| KOI-7863.01 | 0.52 | ||
| KOI-2612.02 | 0.53 | ||
| KOI-4657.01 | 0.54 | ||
| KOI-8257.01 | 0.54 | ||
| KOI-115.03 (Kepler-105d) | [6] | ||
| KOI-2421.01 | 0.55 | ||
| KOI-4097.02 | 0.55 | ||
| KOI-7645.01 | 0.55 | ||
| KOI-3208.01 | 0.56 | ||
| KOI-6763.01 | 0.56 | ||
| KOI-2859.03 | 0.57 | ||
| KOI-4146.02 | 0.57 | ||
| KOI-2859.04 | 0.57 | ||
| KOI-7873.01 | 0.57 | ||
| TOI-4307.02 | |||
| KOI-2657.01 | 0.58 | ||
| KOI-8277.01 | 0.58 | ||
| KOI-4296.01 | 0.59 | ||
| KOI-3196.01 | 0.59 | ||
| KOI-5692.01 | 0.59 | ||
| KOI-1964.01 | 0.6 | ||
| KOI-4407.01 | 0.6 | ||
| KOI-4871.01 | 0.6 | ||
| KOI-5211.01 | 0.6 | ||
| KOI-7888.01 | 0.6 | ||
| KOI-3184.03 | 0.6 | ||
| KOI-8183.01 | 0.6 | ||
| KOI-3083.02 | 0.61 | ||
| KOI-4421.01 | 0.61 | ||
| KOI-4716.01 | 0.61 | ||
| KOI-3102.01 | 0.61 | ||
| KOI-7032.01 | 0.61 | ||
| KOI-1843.03 | |||
| KOI-1499.02 | 0.62 | ||
| KOI-605.02 | 0.62 | ||
| KOI-7676.01 | 0.62 | ||
| KOI-4849.01 | 0.62 | ||
| KOI-365.02 | 0.62 | ||
| KOI-7116.01 | 0.62 | ||
| KOI-4421.02 | 0.62 | ||
| KOI-7949.01 | 0.62 | ||
| KOI-2029.04 | 0.63 | ||
| KOI-6889.01 | 0.63 | ||
| KOI-2636.02 | 0.63 | ||
| KOI-3248.01 | 0.64 | ||
| KOI-5213.01 | 0.64 | ||
| KOI-6276.01 | 0.64 | ||
| KOI-7617.01 | 0.64 | ||
| KOI-7903.01 | 0.64 | ||
| KOI-7925.01 | 0.64 | ||
| KOI-8174.01 | 0.64 | ||
| KOI-3083.03 | 0.65 | ||
| KOI-4875.01 | 0.65 | ||
| KOI-4808.01 | 0.65 | ||
| KOI-6568.01 | 0.65 | ||
| KOI-1619.01 | 0.66 | ||
| KOI-3111.02 | 0.66 | ||
| KOI-2859.05 | 0.66 | ||
| KOI-3017.01 | 0.67 | ||
| KOI-4907.01 | 0.67 | ||
| KOI-1616.02 | 0.67 | ||
| KOI-6299.01 | 0.67 | ||
| KOI-8211.01 | 0.67 | ||
| KOI-2593.02 | 0.68 | ||
| KOI-4605.01 | 0.68 | ||
| KOI-7832.01 | 0.68 | ||
| KOI-7483.01 | 0.68 | ||
| KOI-2623.02 | 0.68 | ||
| KOI-7924.01 | 0.68 | ||
| KOI-7628.01 | 0.69 | ||
| KOI-4129.01 | 0.69 | ||
| KOI-4822.01 | 0.69 | ||
| KOI-6600.01 | 0.69 |