Convert VBA to Cross-Platform Macros: Making Templates Work in LibreOffice and Excel

Stop losing hours to platform lock-in: make your VBA templates work in LibreOffice and Excel

Hook: If your team spends precious time maintaining .xlsm files that break on Linux or macOS, or you’re stuck rewriting the same macros for clients using LibreOffice, this guide shows how to convert VBA to truly cross-platform automations — using LibreOffice Basic, Python, or Power Query — with test cases and conversion templates you can apply today.

The migration imperative in 2026

By early 2026 many small businesses and public-sector teams are mixing Microsoft 365, Excel Desktop, and LibreOffice. Cost pressures and data privacy policies push organisations to adopt LibreOffice, while others keep Excel for advanced analytics and Python integration. That mixed environment creates a new operational pain: macro portability. Macros written in VBA often fail outside Windows Excel because they rely on COM, ActiveX, or Excel-specific objects.

This article gives a pragmatic, step-by-step approach to migrate common VBA macros into three cross-platform options: LibreOffice Basic, Python (embedded or external), and Power Query / M. You’ll get conversion templates, test cases and a realistic migration checklist tuned for UK small businesses and ops teams.

Quick decision framework: which path to choose?

1. Keep simple UI automations (dialogs, small workflows): Convert to LibreOffice Basic if you must run in .ods and keep user forms.
2. Data transformation, ETL or repeatable reports: Convert to Power Query (M) or Python for robustness and performance.
3. Advanced analytics or external integrations: Move to Python (Excel Desktop with Python in Excel, or external scripts) or build an Office Add-in if web integration is needed.

Rule of thumb: Avoid platform-specific features. The less your macro interacts with the Windows-only COM layer, the easier the migration.

Step 1 — Audit your VBA: map the portability risk

Start with a short audit that categorises each macro by portability risk. Use this checklist during the audit:

• Does it reference external libraries (e.g., FileSystemObject, Outlook, ADODB)?
• Does it use ActiveX controls or Worksheet Events tied to COM?
• Does it manipulate shapes, charts or pivot caches with Excel-specific APIs?
• Does it open files with Shell or Windows-only paths?

Score each macro as High / Medium / Low portability. High-risk macros usually need a rewrite; low-risk macros often translate cleanly to LibreOffice Basic or Python.

Step 2 — Understand the target runtime differences

Key differences to anticipate:

• Object model: Excel VBA uses Application.Workbooks(), Worksheets(), Range, etc. LibreOffice Basic uses the UNO API: ThisComponent, Sheets, getCellRangeByName().
• Dialog/UI: VBA UserForms are not directly portable. LibreOffice supports basic dialogs via Dialog Libraries or createUNO components; Python/Power Query prefers task panes or external UIs.
• External services: COM-based Outlook or Windows APIs need replacement with cross-platform libraries or REST APIs (SendGrid, Microsoft Graph).
• Security: Macro signing and user prompts differ — advise customers to trust templates or use signed add-ins.

Conversion templates: three practical examples

Below are three real-world patterns, each with a VBA source and equivalent in LibreOffice Basic, Python, and Power Query where applicable. These are starter templates — adapt them to your data structure and naming conventions.

Example A — Copy range, apply number formats and autofit columns

Scenario: A reporting macro copies a range from a data sheet to a printable sheet, applies currency formatting, and autofits columns.

VBA (original)

Sub CopyAndFormat()
    Dim wsSrc As Worksheet, wsDst As Worksheet
    Set wsSrc = ThisWorkbook.Sheets("Data")
    Set wsDst = ThisWorkbook.Sheets("Report")

    wsDst.Range("A1:Z100").Clear
    wsSrc.Range("A1:Z100").Copy wsDst.Range("A1")
    wsDst.Range("B:B").NumberFormat = "£#,##0.00"
    wsDst.Columns.AutoFit
  End Sub

LibreOffice Basic equivalent

Sub CopyAndFormatLO
    Dim doc As Object, sheets As Object
    Dim src As Object, dst As Object
    doc = ThisComponent
    sheets = doc.Sheets
    src = sheets.getByName("Data")
    dst = sheets.getByName("Report")

    dst.getCellRangeByName("A1:Z100").clearContents(1023) 'all
    src.getCellRangeByName("A1:Z100").copyRange(dst.getCellByPosition(0,0).CellAddress, 25, 99)

    ' Set number format (using locale-aware format string)
    Dim nf As Object
    nf = doc.NumberFormats
    Dim key As Long
    key = nf.queryKey("#,##0.00 \u00A3", "") '£
    dst.getCellRangeByName("B1:B100").NumberFormat = key

    ' Auto-fit columns: iterate columns and set optimal width
    Dim col
    For col = 0 To 25
      dst.Columns.getByIndex(col).OptimalWidth = True
    Next col
  End Sub

Notes: LibreOffice uses UNO; the exact number format key call can vary by locale. Test on macOS/Linux and Windows builds.

Python (Excel Desktop with Python or LibreOffice external script)

from openpyxl import load_workbook

wb = load_workbook('report.xlsx')
src = wb['Data']
dst = wb['Report']

# clear and copy cell values
for r in range(1,101):
    for c in range(1,27):
        dst.cell(row=r, column=c).value = src.cell(row=r, column=c).value

# format
for row in dst.iter_rows(min_row=1, max_row=100, min_col=2, max_col=2):
    for cell in row:
        cell.number_format = '£#,##0.00'

# use openpyxl auto-size (approximate)
for col in dst.columns:
    max_length = max((len(str(cell.value)) for cell in col if cell.value), default=0)
    dst.column_dimensions[col[0].column_letter].width = max_length + 2

wb.save('report_out.xlsx')

Example B — Sort and remove duplicates (data cleansing)

Pattern: Prefer using Power Query (M) or Python for repeatable cleanses. Power Query performs better inside Excel for structured refresh workflows.

Power Query (M) pseudo-template

let
    Source = Excel.CurrentWorkbook(){[Name="DataTable"]}[Content],
    RemovedNulls = Table.SelectRows(Source, each List.NonNullCount(Record.FieldValues(_))>0),
    Sorted = Table.Sort(RemovedNulls,{{"Date", Order.Descending}}),
    Deduped = Table.Distinct(Sorted, {"InvoiceID"})
  in
    Deduped

Why Power Query? It gives refreshable ETL inside the workbook, works across platforms in recent Excel releases (desktop + web), and avoids macro security dialogs. For LibreOffice, similar workflows can be scripted with Python using pandas and saved back.

Example C — Send an email with report attachment

This is often Windows/Outlook-specific. Replace with cross-platform approaches: SMTP via Python, or use REST APIs (SendGrid, Microsoft Graph) for authenticated sending.

VBA (Outlook COM)

Sub SendReport()
    Dim olApp As Object
    Dim olMail As Object
    Set olApp = CreateObject("Outlook.Application")
    Set olMail = olApp.CreateItem(0)
    olMail.To = "client@example.com"
    olMail.Subject = "Monthly Report"
    olMail.Body = "Please find attached."
    olMail.Attachments.Add "C:\Reports\report.xlsx"
    olMail.Send
  End Sub

Python SMTP (cross-platform)

import smtplib
from email.message import EmailMessage

msg = EmailMessage()
msg['Subject'] = 'Monthly Report'
msg['From'] = 'reports@company.co.uk'
msg['To'] = 'client@example.com'
msg.set_content('Please find attached.')
with open('report_out.xlsx', 'rb') as f:
    data = f.read()
    msg.add_attachment(data, maintype='application', subtype='vnd.openxmlformats-officedocument.spreadsheetml.sheet', filename='report.xlsx')

with smtplib.SMTP('smtp.yourprovider.co.uk', 587) as s:
    s.starttls()
    s.login('reports@company.co.uk', 'yourpassword')
    s.send_message(msg)

Security note: Use app passwords or OAuth (Microsoft Graph) in production. Avoid storing plain credentials in templates; prefer secure storage patterns and vaults.

Test cases and automated verification

Every converted macro should come with a small suite of test cases that a non-technical staff member can run. Here are three test cases for Example A (CopyAndFormat):

1. Input: Data sheet with numeric values in B2:B10 with currency values. Run conversion. Expected: Report sheet shows copied values and column B formatted with a £ symbol and two decimals.
2. Input: Data sheet empty. Run conversion. Expected: Report sheet is cleared, no errors shown.
3. Input: Long text in column A. Run conversion. Expected: Column widths increase to fit text without truncation.

Record results in a simple test log file shipped with template bundles. Use conditional formatting or assert rows to highlight failures.

Packaging and licensing for templates marketplace

When you ship converted templates in a marketplace or bundle, follow these practices to reduce support tickets:

• Include both formats: Provide .xlsm (Excel) and .ods (LibreOffice) where possible.
• Ship helper scripts: A small Python or PowerShell installer that configures trusted locations, or auto-updates data sources.
• Clear licensing: Offer a commercial license and customization services. A common model: template purchase + optional conversion/customisation fee (hourly or fixed).
• Support materials: Provide test cases, a troubleshooting guide, and a short migration checklist.

Use semantic versioning and include a CHANGELOG for each release. For custom work, offer hourly support and a fixed-scope conversion package.

Advanced strategies and 2026 trends to leverage

Recent developments through late 2025 and into 2026 create new options and constraints:

• Python in Excel is now mainstream: Many organisations use Python inside Excel for analytics. Migrating VBA logic to Python unlocks powerful libraries (pandas, NumPy) and cross-platform execution.
• Power Query continues to mature: Power Query remains the best in-workbook ETL for Excel-based reporting and is supported across Excel clients more consistently than before.
• LibreOffice UNO stays stable: The UNO API is mature and well-documented; community support and Python bindings make LibreOffice a viable macro host.
• Cloud-first integrations: Use REST APIs rather than local COM objects for email, file storage and auth — this reduces platform-specific code and simplifies governance.

Future prediction: In 2026 the winning strategy for many small businesses will be hybrid: keep lightweight UI actions in the spreadsheet and move heavy data work to Python/Power Query pipelines that can run on both Windows and Linux servers.

Common pitfalls and how to avoid them

• Avoid reliance on Windows paths or backslashes — use os.path in Python or relative URIs in LibreOffice.
• Don’t embed credentials in macros. Use OAuth tokens, environment variables or secure vaults.
• Beware of locale-specific number and date formats. Include tests that use UK date formats and currency.
• UserForms are fragile across platforms. Rebuild essential UIs as simple sheets, HTML/Task Pane add-ins, or small web forms.

Practical migration checklist (actionable)

1. Run the portability audit and classify macros (High/Med/Low).
2. Pick migration approach per macro (LibreOffice Basic / Power Query / Python / Add-in).
3. Write conversion template with comments and inputs/outputs clearly labelled.
4. Create 3–5 test cases and an automated test script where possible.
5. Package both .xlsm and .ods (if applicable) with a README and license file — use an installation-ready README.
6. Provide an installation note for trusted locations and macro security steps for Windows/macOS/Linux.

Case study (brief): A UK operations team

We migrated a 12-macro financial template for a mid-sized UK operations team in late 2025. The original workbook used Outlook COM, pivot cache manipulation and ActiveX buttons. Our approach:

• Replaced Outlook COM with Microsoft Graph REST calls via Python (server-side) for scheduled emails.
• Moved pivot refresh and heavy transforms to Power Query for refreshability.
• Rewrote small sheet-copy macros in LibreOffice Basic for the employees using .ods on Linux PCs.

Result: 80% fewer support tickets, faster automated refreshes, and a clear licence + support contract for template maintenance.

“Converting logic, not line-by-line code, is the secret. Choose the right runtime for the task.”

Getting started: downloadable assets and services

We provide conversion starter kits for common macro patterns: data copy & format, cleanse & dedupe, dashboard refresh, and automated emails. Each kit includes:

• VBA original + LibreOffice Basic translation + Python / Power Query variants
• 3 test cases and a test-run checklist
• Installation notes for trusted locations and macro security
• Licensing templates for template resale and white-labeling

These kits are offered as part of bundles on our template marketplace, with optional customisation and on-site migration services for UK businesses.

Final checklist before go-live

• All test cases pass on Windows, macOS and a Linux desktop build (LibreOffice).
• Credential handling uses secure storage — no plaintext passwords in templates.
• Users have clear instructions to enable macros or run the installed helper script.
• Documentation includes fallback steps and contact details for paid support.

Conclusion and call-to-action

Migrating VBA to cross-platform macros is not about translating code line-for-line — it’s about choosing the right execution model for each task, reducing platform-specific dependencies, and shipping robust testable templates. In 2026 the toolkit is richer: use LibreOffice Basic for lightweight, in-file UIs; Power Query for refreshable ETL; and Python for advanced processing and integrations.

If you’re ready to stop firefighting incompatible macros, get our free conversion starter kit that includes the examples above, test cases and packaging templates — or contact our team for a fixed-price migration audit and custom conversion service for your template bundles.

Take action now: Download the free starter kit or request a migration quote to standardise your reporting across Excel and LibreOffice and reduce maintenance overhead.

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