VBA Dictionary: Fast Lookups and Unique Lists in Your Macros

📎 This article includes 1 downloadable practice file ↓

⏱ 2 min readUpdated 28 September 2026

Looping through 50,000 rows and calling VLOOKUP for each one is slow. A Dictionary stores key → value pairs in memory and finds any key instantly.

In this article
  1. Create one
  2. Unique list with counts
  3. Replace a lookup loop
  4. Useful members

Create one

Dim d As Object
Set d = CreateObject("Scripting.Dictionary")   ' late binding: no reference needed
d.CompareMode = vbTextCompare                     ' "delhi" = "Delhi"

Unique list with counts

Sub CountByRegion()
    Dim d As Object, arr, i As Long, k
    Set d = CreateObject("Scripting.Dictionary")
    arr = Sheets("Data").Range("B2:B50001").Value      ' read once into memory
    For i = 1 To UBound(arr)
        If arr(i, 1) <> "" Then d(arr(i, 1)) = d(arr(i, 1)) + 1
    Next i
    i = 2
    For Each k In d.Keys
        Sheets("Summary").Cells(i, 1).Value = k
        Sheets("Summary").Cells(i, 2).Value = d(k)
        i = i + 1
    Next k
End Sub

Replace a lookup loop

' load price list: code -> price
For i = 2 To lastPrice: prices(wsP.Cells(i, 1).Value) = wsP.Cells(i, 3).Value: Next i
' then, for each order row:
If prices.Exists(code) Then price = prices(code) Else price = "Not found"

Useful members

Member Does
.Exists(key) Is the key there?
.Count Number of keys
.Keys / .Items Arrays of keys / values
.Remove key, .RemoveAll Delete entries
💡 Reading the range into an array first (arr = Range(...).Value) matters as much as the dictionary. Together they often turn minutes into under a second.

📎 Practice files for this article

  • 📗
    Dictionary practice workbook (.xlsm)5,000 orders with messy region names. Two macros: one merges variants correctly, one shows what goes wrong without cleaning.
    ⬇ XLSM · 145 KB

Free to use for learning. Files with macros (.bas) are plain text — import them with Alt+F11 → File → Import File, and always test on a copy.

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