swexcel

swexcel_logo

Swiss Ephemeris for 64-bit Excel & VBA

A VBA implementation of the Swiss Ephemeris by Astrodienst AG, packaged as a ready-to-use 64-bit Excel spreadsheet. Calculate natal charts, Cosmodynes (planet/sign/house power scores), and precise transit dates — all from inside Excel.

[!WARNING] Windows only. The calculation engine is a native Windows DLL (swedll64.dll, a 64-bit PE binary). Because of how DLLs work, it can only be loaded by 64-bit Microsoft Excel on Windows. It will not run on Excel for macOS (Apple Silicon or Intel) or on 32-bit Excel. You can clone and edit this repo on any OS — including a Mac — but the spreadsheet only executes on Windows Excel, natively or inside a Windows VM (Parallels, VMware, UTM, etc.).

Features

Requirements

Component Details
Excel 64-bit, Microsoft 365 / Office 2016 or later (Windows only)
Swiss Ephemeris DLL swedll64.dll (Swiss Ephemeris 2.10.03, Astrodienst prebuilt) — included in ephem/
Ephemeris data files SEPL_18.SE1, SEMO_18.SE1, SEAS_18.SE1 (JPL DE441) — included in ephem/
Macros Must be enabled in Excel Trust Center

Note: This project is Windows-only. The 64-bit DLL cannot be loaded by 32-bit Excel or Excel on macOS.

Repository Layout

swexcel/
├── Cosmodynes and Transits SE spreadsheet_64bit.xls   # Main workbook
├── ephem/
│   ├── swedll64.dll          # 64-bit Swiss Ephemeris DLL
│   ├── swedll64.lib          # Import library
│   ├── sweph_vb7_64.bas      # Original VB7 declarations reference
│   ├── SEPL_18.SE1           # Planet ephemeris data
│   ├── SEMO_18.SE1           # Moon ephemeris data
│   ├── SEAS_18.SE1           # Asteroid ephemeris data
│   └── asteroids/
│       └── SEAS_18.SE1       # Additional asteroid data
└── vba/                      # Extracted VBA module source files
    ├── GeneralDeclarations.vba
    ├── PrintCosmodynes.vba
    ├── Get_transit_date_and_time.vba
    ├── CalcPlanetAspectPower.vba
    ├── CalcPlanetHousePower.vba
    ├── CalcHousePower.vba
    ├── CalcSignPower.vba
    ├── Dignities.vba
    ├── Reception.vba
    ├── Get_natal_data.vba
    ├── Get_1_Planet.vba
    ├── Get_1_Planet_geo.vba
    ├── Get_1_Planet_decl.vba
    ├── Get_Ascendant.vba
    ├── Get_MC.vba
    ├── PLANETSINHOUSES.vba
    ├── FigureHouseInterceptions.vba
    ├── FigureSignInterceptions
    ├── SecantMethod.vba
    └── ... (utility modules)

Installation

1. Place the DLL where Excel can find it

Copy swedll64.dll to a directory on your system PATH, such as:

C:\sweph\bin\swedll64.dll

The DLL path is hardcoded in GeneralDeclarations.vba. If you place the DLL elsewhere, open the VBA editor (Alt + F11) and update every Lib "C:\sweph\bin\swedll64.dll" declaration to match your chosen path.

2. Copy the ephemeris data files

Place the .SE1 files from ephem/ in the same directory as the DLL, or in a location that Swiss Ephemeris can resolve at runtime:

C:\sweph\bin\SEPL_18.SE1
C:\sweph\bin\SEMO_18.SE1
C:\sweph\bin\SEAS_18.SE1

3. Open the workbook

Open Cosmodynes and Transits SE spreadsheet_64bit.xls in 64-bit Excel. When prompted, choose Enable Macros.

4. Enter birth data

Fill in the input cells on Sheet1:

Cell Value
A2 Month
B2 Day
C2 Year
D2 Hour (local time)
E2 Minute
F2 Second
G2 UTC offset (hours)
H2 Longitude (decimal degrees, West negative)
I2 Latitude (decimal degrees, South negative)

5. Run the calculations

Click the Cosmodynes button (or run PrintCosmodynes from the Macros dialog) to populate the output tables.

Upgrading the Swiss Ephemeris engine

This repo ships Swiss Ephemeris 2.10.03 (Astrodienst’s prebuilt 64-bit DLL) with JPL DE441 data files. Refreshing or re-applying the engine is a binary + data swap — no VBA changes are required, because the Declare signatures in GeneralDeclarations.vba (and the ephem/sweph_vb7_64.bas reference copy) already match the 2.10 API.

Files to download

Everything comes from the official Astrodienst repository: https://github.com/aloistr/swisseph

File Where in the repo Notes
swedll64.dll windows/sweph.zip → unzip → sweph/bin/swedll64.dll 999,936 bytes, CRC-32 5bf1f794 — the engine
swedll64.lib same zip → sweph/bin/swedll64.lib 23,230 bytes, CRC-32 142ad89d — C-link import lib only (not needed at VBA runtime)
sepl_18.se1 ephe/sepl_18.se1 planets, JPL DE441 (rebuilt 14 Apr 2026), ~0.5 MB
semo_18.se1 ephe/semo_18.se1 Moon, DE441, ~1.3 MB
seas_18.se1 ephe/seas_18.se1 main asteroids incl. Chiron, DE441, ~218 KB

For each data file, use GitHub’s Download raw button, or fetch https://github.com/aloistr/swisseph/raw/master/ephe/<name>.

Where to put them

  1. Runtime location — what Excel actually loads. Per this project’s install that is C:\sweph\bin\. Replace: 
    C:\sweph\bin\swedll64.dll
C:\sweph\bin\sepl_18.se1
C:\sweph\bin\semo_18.se1
C:\sweph\bin\seas_18.se1
  2. Repo copy — source of truth. Replace the matching files in ephem/ (and the duplicate ephem/asteroids/SEAS_18.SE1). Windows filenames are case-insensitive, so the existing SEPL_18.SE1 etc. and the lowercase downloads are interchangeable.

[!NOTE] The shipped prebuilt (swedll64.dll, CRC-32 5bf1f794) reports 2.10.03 via swe_version() — verified from the binary. To build your own from source instead, use the Visual Studio project sweph/src/projects/swedll64.vcxproj inside sweph.zip.

Verify it worked

  1. Version — in the VBA Immediate window (Alt+F11, then Ctrl+G): 
    ?dll_version()

    It should return 2.10.03 (no longer 1.60).

  2. Positions — for 2000-01-01 12:00 UT (Julian Day 2451545.0), geocentric tropical longitudes. Your Swiss/DE441 result should match these to within ~0.01°:

    Body Longitude Body Longitude
    Sun 280.369° (10°22′ ♑) Jupiter 25.253° (25°15′ ♈)
    Moon 223.324° (13°19′ ♏) Saturn 40.396° (10°24′ ♉)
    Mercury 271.889° (1°53′ ♑) Uranus 314.809° (14°49′ ♒)
    Venus 241.566° (1°34′ ♐) Neptune 303.193° (3°12′ ♒)
    Mars 327.963° (27°58′ ♓) Pluto 251.455° (11°27′ ♐)
    Mean Node 125.041° (5°02′ ♌) True Node 123.953° (3°57′ ♌)

    Placidus houses at 40°N, 75°W for the same instant: ASC 273.84°, MC 207.42°. (References computed with Swiss Ephemeris 2.10.03 via pyswisseph — Moshier model, which agrees with the DE441 .se1 files to <0.01°.)

Usage

Cosmodynes report

Running PrintCosmodynes calculates and prints:

Transit finder

Get_transit_date_and_time(sm, sd, sy, em, ed, ey, p_num, start_pos, angle) returns a date/time string for when planet p_num completes the given angle from start_pos within the search window [sm/sd/sy … em/ed/ey].

' Find when Mars reaches 15° Aries between 1 Jan 2025 and 31 Dec 2025
Dim result As String
result = Get_transit_date_and_time(1, 1, 2025, 12, 31, 2025, SE_MARS, 0, 15)
MsgBox result

Technology Stack

Layer Technology
Host application Microsoft Excel (64-bit, Windows)
Calculation engine Swiss Ephemeris 2.10.03 (swedll64.dll, Astrodienst prebuilt) — JPL DE441 ephemeris
Programming language VBA (Visual Basic for Applications) with PtrSafe 64-bit declarations
Ephemeris data format Swiss Ephemeris binary .SE1 files, JPL DE441 rebuild (1800–2400 CE coverage)
Numerical solver Secant method (SecantMethod.vba) for transit time refinement

Swiss Ephemeris Planet Constants

The following constants from GeneralDeclarations.vba are available in all VBA modules:

Constant Value Body
SE_SUN 0 Sun
SE_MOON 1 Moon
SE_MERCURY 2 Mercury
SE_VENUS 3 Venus
SE_MARS 4 Mars
SE_JUPITER 5 Jupiter
SE_SATURN 6 Saturn
SE_URANUS 7 Uranus
SE_NEPTUNE 8 Neptune
SE_PLUTO 9 Pluto
SE_CHIRON 15 Chiron

Contributing

Contributions are welcome. Please:

  1. Fork the repository
  2. Create a feature branch (git checkout -b feature/my-improvement)
  3. Export any changed VBA modules as .vba text files into the vba/ directory so diffs are readable
  4. Open a pull request describing what you changed and why

Bug reports and feature requests can be filed via GitHub Issues.

License

This project is released under the GNU General Public License v2.0 or later, consistent with the Swiss Ephemeris library it wraps.

The Swiss Ephemeris itself is copyright © Astrodienst AG and is used here under its GPL license. See https://www.astro.com/swisseph/swephinfo_e.htm for the upstream license terms.