Lunar age calculator form
Enter your birth moment, choose a target date, and compare your solar age with moon-based age values.
Plotly graph
The graph compares age growth under solar-year and lunar-year assumptions from birth to the selected target date.
Example data table
This sample shows how the calculator works with a fixed birth date and target date.
| Birth moment | Target moment | Lunar age (years) | Lunar months lived | Solar age (years) | Next lunar birthday |
|---|---|---|---|---|---|
| Jan 01, 2000 00:00 | Mar 26, 2026 00:00 | 27.0369 | 324.4433 | 26.2319 | Mar 02, 2027 06:39 |
Formula used
1) Elapsed days
Elapsed Days = (Target Timestamp − Birth Timestamp) ÷ 86,400
2) Lunar age in years
Lunar Age Years = Elapsed Days ÷ Lunar Year Length
3) Lunar months lived
Lunar Months Lived = Elapsed Days ÷ Lunar Month Length
4) Solar age in years
Solar Age Years = Elapsed Days ÷ Solar Year Length
5) Remaining days after full lunar year
Remaining Days = Elapsed Days − floor(Lunar Age Years) × Lunar Year Length
Default values use an average synodic month and a twelve-month lunar year. You can edit those constants for different study needs.
How to use this calculator
- Enter your birth date. Add birth time if you know it.
- Choose the target date and optional target time.
- Keep the default lunar constants or adjust them.
- Select decimal precision and press Calculate lunar age.
- Review the result summary, data table, and graph.
- Use the CSV or PDF buttons to save the result.
Frequently asked questions
1) What does lunar age mean?
Lunar age expresses your age using moon-based cycles. This calculator converts your lived days into lunar months and lunar years using average cycle lengths.
2) Is lunar age the same as a Hijri age?
No. This tool uses average mathematical lunar lengths. Official religious or civil lunar calendars may differ because month starts can follow rules or observation methods.
3) Why is lunar age usually larger than solar age?
A lunar year is shorter than a solar year. Because each lunar year has fewer days, more lunar years fit into the same lifetime span.
4) Should I enter birth time?
Entering time improves precision, especially for exact milestone comparisons. If you do not know it, leaving midnight is usually fine for everyday estimates.
5) What month length does the calculator use by default?
It uses 29.530588 days, the average synodic lunar month. That value represents the typical time from one new moon to the next.
6) Can I change the lunar year length?
Yes. The form lets you edit lunar month, lunar year, and solar year lengths. That makes the tool useful for experiments, teaching, and comparison studies.
7) Why can official lunar birthdays differ from this result?
Some calendars use observational rules, timezone differences, or fixed arithmetic tables. This tool instead uses continuous average cycle math, so exact calendar dates can vary.
8) Can I save or share my result?
Yes. After calculating, use the CSV button for spreadsheet-friendly data or the PDF button for a clean summary you can save, print, or share.