Moon Phase Calculator

Select any calendar date. Oracle Mirror estimates lunar age from a known new-moon epoch and the average 29.53058867-day synodic month. This is useful for a lightweight phase guide, but it is not a precision ephemeris.

The eight phase labels

🌑New MoonThe Moon is near conjunction with the Sun, so its sunlit hemisphere is mostly turned away from Earth.🌒Waxing CrescentA growing crescent becomes visible after new moon as the Moon moves eastward from the Sun in the sky.🌓First QuarterRoughly half of the visible lunar disk is illuminated while the Moon is about 90 degrees east of the Sun.🌔Waxing GibbousMore than half of the visible disk is illuminated and the illuminated fraction continues increasing toward full moon.🌕Full MoonThe Moon is near opposition to the Sun, with its Earth-facing hemisphere largely illuminated.🌖Waning GibbousThe visible illuminated fraction decreases after full moon while more than half the lunar disk remains lit.🌗Last QuarterAbout half of the visible lunar disk is illuminated while the Moon is roughly 90 degrees west of the Sun.🌘Waning CrescentOnly a shrinking crescent remains visible before the Moon returns to conjunction with the Sun.

How accurate is this?

The calculator models the average synodic cycle. Real lunar phase timing varies because the Moon's orbit is not uniform, so exact event times should come from an astronomical ephemeris. Oracle Mirror deliberately labels the result approximate.