Free Zi Wei Dou Shu Calculators Compared: 6 Charts in English

Enter the same birthday into two Zi Wei Dou Shu calculators and you will sometimes get two different charts. Usually neither is broken. They just follow different rules: how the birth time is corrected, how a leap month is split, and which day counts for a birth after 11 p.m. So rather than asking which calculator is "most accurate," it helps to ask which rules it uses, and whether those are the rules you want.

This guide compares six free calculators that English searchers commonly find. The details come from each site's own pages, checked in October 2026. Where a site doesn't say how it handles something, we mark it "not stated," which doesn't mean the feature is missing. One disclosure up front: Xingge is our own site and is included in the list. We've tried to describe every tool by the same yardstick.

Five things worth checking

1. Do you need an account?

If you just want to see which star sits in your Life Palace, a calculator that needs no sign-up is quickest. If you plan to keep charts for family and friends, an account that saves them is handy.

2. Is daylight saving taken out?

Zi Wei Dou Shu is cast from the local clock time where you were born. If daylight saving was in force that day, the clock was an hour ahead, and the hour has to come off before the chart is cast, or your birth hour can land in the wrong double-hour. Some calculators do this automatically from your birthplace; others ask you to subtract the hour yourself.

3. True solar time: on or off?

True solar time adjusts the clock time to where the sun actually was, using your birthplace's longitude. Practitioners disagree about it, and the classical texts don't use it. Calculators that offer it usually let you switch it on or off.

4. Leap months and the late Zi hour

For people born in a lunar leap month, schools differ on whether it counts as the current month, the next month, or splits at the fifteenth day. For births between 11 p.m. and midnight (the late Zi hour), some tools use the same day and some the next. Both rules change the chart directly, so check them first when two charts disagree.

5. Readings, and what costs money

Some tools give you the chart only. Some add plain-English readings. Others keep the chart free and charge for detailed reports, courses or consultations.

Six free calculators at a glance

What each one does well

Master Sean Chan

Site: Master Sean Chan

A calculator from a Chinese metaphysics consultant that needs no sign-up. The chart shows the 14 major stars, 31 auxiliary stars, brightness levels and the Four Transformations, and you can switch between the natal, decade and annual charts. It takes birth dates from 1900 to 2100 and has a solar time adjustment with country, city, longitude and UTC fields. Its FAQ is clear that the calculator doesn't interpret the chart for you. Good for people who want a detailed chart and plan to read it themselves.

Zi Wei Dou Shu Calculator

Site: Zi Wei Dou Shu Calculator

A simple, English-first calculator built on the open-source iztro engine, describing itself as free, deterministic, and in English and Chinese. The home page shows the 12 palaces, 14 major stars and Four Transformations, with free guide text written from standard reference material. Birth hour is chosen from two-hour slots, with 23:00 to 00:59 treated as the early Zi hour. Good for a quick first look and for people curious about how the algorithm works.

sng-mia

Site: sng-mia

Free, with no registration and no usage limit; logging in only saves your charts. It covers the 12 palaces, 14 major stars, Four Transformations, decade and annual charts and brightness, with lunar input and a leap-month flag. Advanced options include minute-level true solar time corrected for birthplace longitude and daylight saving, plus separate early and late Zi choices. The chart overview is free; decade and topic reports are a one-time paid unlock. It says AI is used only for the interpretation, not to cast the chart. Good for people who want fine control over time settings.

OpenFate

Site: OpenFate

Run by OPENFATE AI LLC. You can create and inspect the basic chart without signing up. It uses your birthplace for longitude, historical time zone and daylight saving, and applies true solar time. The day boundary can be set to 23:00 or 00:00, and it states its leap-month convention and its school, Zhongzhou in the Wang Tingzhi lineage. AI readings may need an account and credits. Good for people who want to see exactly which rules produced their chart.

Destiny and Luck

Site: Destiny and Luck

An older, straightforward site with a free chart and a free luck chart, plus two calculators for paid members. It asks you to subtract an hour yourself if you were born during daylight saving, and states that the Chinese day starts at 11 p.m. It also explains the school variant it chooses for one of the year transformations. Good for people who like a plain tool that explains its choices.

Xingge

Site: Xingge's free chart

Our own site. No sign-up is needed, and charts are cast by the rules of the classic Zi Wei Dou Shu Quan Shu (The Complete Book of Zi Wei Dou Shu), with star placement, brightness and the Four Transformations checked against the text and locked in by automated tests. Choose your birth city and Xingge checks the international time zone database for daylight saving in force there on that day, then takes it out automatically. True solar time is optional and off by default. A leap month splits at the fifteenth day, and a birth after 11 p.m. counts as the next day. Every palace and every main star comes with a free plain-English reading, and there are 51 free beginner lessons; books and Ask points are one-time purchases, with no subscription. Every place we depart from the Quan Shu is listed on How Xingge casts a chart.

How to choose

• You just want your Life Palace star: pick a calculator with no sign-up, cast the chart and look at the Life Palace. If you're not sure how to read it, start with the beginner's guide.
• You were born during daylight saving: use a calculator that corrects it from your birthplace, or subtract the hour yourself before entering the time.
• You were born in a leap month or after 11 p.m.: check which rule the calculator uses, then compare its result with a second calculator.
• You want to compare schools: pick a tool that lets you change the leap-month rule, day boundary or transformation table.
• You want readings in plain English: pick a calculator that includes interpretation text, not just the chart.

One last tip: cross-check your chart with a second calculator. If the Life Palace star, the Body Palace and the Four Transformations match, you can read on with confidence. If they don't, go back to the five checks above. If your Life Palace turns out to have no main star, see how to read an Empty Life Palace. To try Xingge, draw your free chart.