# Free Moon sign calculator

Find your Moon sign, including both possible signs when your birth time is unknown. Free, private, computed in your browser.

You need your birth date, time and place. It’s free and takes a minute.

## Start with your birth data

The Moon changes sign about every two and a half days. Without a birth time, we check the whole local day and show both signs when needed.

See an example

## Common questions

### Why are my houses different from those on other sites?

Astraluno uses Whole Sign houses; many sites use Placidus. Both are traditional methods. Signs and planets do not change.

### How accurate is the calculation?

Planet positions were checked against NASA JPL Horizons: a maximum gap of 0.34 arcminutes over 310 positions. The Ascendant was checked on 68 cases. We use historical time zones with daylight saving rules.

### Is Astraluno free?

Yes. The calculator and all readings are free, without an account or payment card.

### Can I calculate a chart without my birth time?

Yes. We check the full local day and show possible signs. Without a time, the rising sign and houses are unavailable.

### Are birth details sent to the server?

No. Date and time are processed in the browser. The server receives the city search query and the request for the time-zone file.

## Links

- [See an example](https://astraluno.com/example-birth-chart/)

Canonical: https://astraluno.com/moon-sign-calculator/
Last revised: 2026-10-13