Astronomical
A live countdown to the next full moon, calculated from where we are in the current ~29.5-day lunar cycle.
This uses the same known-reference-new-moon method as the Moon Phase Calculator — counting days since a confirmed new moon and dividing by the average 29.53-day synodic month to find where the current cycle sits, then projecting forward to the next full-moon point (the midpoint of the cycle). It's accurate to within roughly a day for any given date, which is precise enough for planning but not for professional astronomy.
Related
The full phase breakdown for any date, not just full moons.
The next seasonal marker, sourced from precise astronomical tables.
Sunrise and sunset times for any date and location.