Tool
Day Master Calculator
Find the heavenly stem on your day pillar — the single stem a Bazi chart is read against — without signing up or entering an email. Enter your Gregorian birth date, add a time if you know it, and the chart engine will show your Day Master alongside the full Four Pillars so you can verify the result against the rest of the chart.
What this page is. The Day Master is the heavenly stem of the day pillar. It depends on the civil date in nearly every case. The current version computes it from the date (and, if known, time) you submit, using the published sect 2 day-boundary convention from the reference library lunar-typescript 1.8.6 (MIT). True solar time, longitude, historical time zones, and DST are NOT applied. See the methodology page for the full rule.
What this page is not. The Day Master identity (the stem, its element, its polarity) is the only thing reported here. No strength score, no personality reading, no prediction. For the structural labels around the chart (Ten Gods, Hidden Stems), see the Ten Gods explainer and the Hidden Stems explainer.
Calculate your Day Master
Day Master — frequently asked questions
The Day Master (日主) is the heavenly stem on top of the day pillar — the heavenly stem that sits over the Earthly Branch recording the exact Gregorian day you were born on. Every other stem on the chart is read in relation to it.
This page uses the civil date and (optional) time you submit together with the published sect 2 day-boundary convention from the reference library lunar-typescript 1.8.6 (MIT). True solar time, longitude, historical time zones, and DST are NOT applied — the engine works entirely from the civil date / time. The full method, including the 23:00–23:59 late Zi convention, is documented on the methodology page.
If you know your birth time, enter the actual civil time. If you do not know it, tick "I do not know the birth time" — the engine will then only compute from the civil date and cannot resolve late-Zi or midnight boundary uncertainty. This page does not auto-detect those boundaries; cross-check the methodology page for the full rule.
No. The Day Master identity — the stem, its element, and its yin/yang polarity — is the only thing this page reports. Strength, balance, personality, and outcome interpretations belong to a separate reading step and are not produced here.