FAQ
Answers to the questions we are asked most often about Horoscho Chart. If yours is not here, please contact us.
About the app
What is Horoscho Chart?
Horoscho Chart (Astrologer's ToolBox) is a web app for Western astrology. It calculates natal charts, bi-wheels, tri-wheels and 5-wheels, timing tables, declination graphs, midpoints and harmonics, graphic ephemerides, void-of-course calendars, fixed stars and parans, LIFELOG and more — all inside your browser.
Do I need to install anything?
No. Just open toolbox.horoschola.jp/app/ — it runs entirely in the browser, on Windows, Mac and smartphones. For reading charts we recommend a computer with a large screen.
How accurate are the calculations?
We use the Skyfield astronomy library with the JPL (NASA Jet Propulsion Laboratory) ephemerides DE440 / DE441 — the same data used in professional astronomy. Planetary positions agree with Swiss Ephemeris / astro.com to within one arc-minute. The supported range is 3000 BC to AD 2200.
Which languages are supported?
Seven: Japanese, English, Spanish, Italian, Portuguese, French and German. The app switches automatically to match your browser, and you can change the language any time in the settings. In keeping with the idea of learning in your mother tongue, more languages will be added over time.
Pricing and use
How much does it cost?
Chart creation is free for everyone — no fee, no account. Only AI Readings are an optional monthly subscription: Basic at $12 / month and Pro at $25 / month (revised 1 September 2026).
Do I need an ID or password?
No login is needed to create charts. Only AI Readings require signing in, and that works through a link sent to your email — there is no password to remember.
Can I use it on several devices?
Yes. Saved data, however, is stored separately in each browser, so to use the same data on another device, move it by export/import (or by syncing with your own Google Drive).
May I publish the charts I create?
Yes. You are free to publish them on blogs, X and other social media, to use them in your readings, and to hand them out to students in your courses. You may also use them in publications, at your own responsibility. Chart images themselves may not be sold.
Data and privacy
Where is my data stored?
In your own browser (localStorage / IndexedDB); it is never sent to our server. If you clear your browser data, your saved charts are deleted too, so we recommend exporting important data to a file.
What is sent when I use AI Readings?
Only when you press the "AI Reading" button, your chart data (date, time and place of birth, and the calculated positions) and the text in the "on your mind" field are sent to Google's Gemini API via our own server. Your name is not sent unless you switch that option on in the settings. See the Privacy Policy for details.
AI Readings
What are AI Readings?
Based on the chart you have created, the AI writes a reading. You can then continue the conversation to explore what interests you (up to 10 exchanges per reading, at no extra charge). Everything runs from a single button — you never have to write a prompt yourself.
Can I use the app without AI Readings?
Yes. Everything other than AI Readings is free, and you can use the whole app without them.
Support
I found a bug
Please let us know via Contact. Horoscho Chart is developed by one person, but issues are dealt with as quickly as possible. It helps a lot if you say which screen you were on, what you did, and what happened.
Where do I send requests?
Also via Contact. Users' feedback shapes what comes next.