Office Scripts vs VBA: Which Excel Automation Should You Use?

Side-by-Side Comparison

The Same Task in Both

VBA

Sub MarkOverdue()
    Dim ws As Worksheet, r As Long, lastRow As Long, n As Long
    Set ws = ThisWorkbook.Worksheets("Invoices")
    lastRow = ws.Cells(ws.Rows.Count, "A").End(xlUp).Row
    For r = 2 To lastRow
        If ws.Cells(r, "D").Value < Date And ws.Cells(r, "E").Value > 0 Then
            ws.Rows(r).Interior.Color = RGB(255, 230, 230)
            n = n + 1
        Else
            ws.Rows(r).Interior.ColorIndex = xlNone
        End If
    Next r
    ThisWorkbook.Worksheets("Summary").Range("B2").Value = n
End Sub

Office Script

function main(workbook: ExcelScript.Workbook): number {
  const sheet = workbook.getWorksheet("Invoices");
  const used = sheet.getUsedRange();
  const values = used.getValues();
  const today = new Date(); today.setHours(0, 0, 0, 0);
  let overdue = 0;

  for (let i = 1; i < values.length; i++) {
    const due = new Date(Math.round(((values[i][3] as number) - 25569) * 86400 * 1000));
    const balance = values[i][4] as number;
    const row = used.getRow(i).getFormat().getFill();
    if (due < today && balance > 0) { row.setColor("#FFE6E6"); overdue++; }
    else { row.clear(); }
  }
  workbook.getWorksheet("Summary").getRange("B2").setValue(overdue);
  return overdue;   // returned value is available to Power Automate
}

When Office Scripts Are the Better Choice

• Workbooks already live in SharePoint or OneDrive and are edited in the browser.

• Users include Mac or web-only users where VBA is limited or unavailable.

• The process should run on a schedule or when something happens (a file arrives, a form is submitted).

• IT restricts macros but allows Microsoft 365 automation.

• The output goes to Teams, SharePoint lists or other cloud services.

When VBA Is Still the Right Tool

• Heavy desktop interaction: generating Word documents, driving classic Outlook, working with local and network files.

• Event-driven workbooks: validation on change, protected input sheets, custom forms.

• Large existing VBA solutions that work; rewriting has to pay for itself.

• Offline use, or environments without Microsoft 365 business plans.

A Typical Cloud Flow

Power Automate flow (every weekday at 7:00):
1. Run script "RefreshAndSummarise" on Sales.xlsx in SharePoint
2. Get the returned summary values
3. Condition: if overdue > 0
4. Send an email (Outlook connector) to collections with the summary
5. Post a message to the Finance channel in Teams

Migrating Macros to Office Scripts

• List what the macro does; separate data preparation (move to Power Query), workbook changes (Office Script) and external actions (Power Automate).

• Rewrite in small scripts that each do one job and return values to the flow.

• Read and write ranges as arrays; cell-by-cell calls are slow in scripts too.

• Test with copies in SharePoint before switching users over.