diff --git a/Examples/Tables/TotalsRow.ps1 b/Examples/Tables/TotalsRow.ps1
new file mode 100644
index 0000000..1580dae
--- /dev/null
+++ b/Examples/Tables/TotalsRow.ps1
@@ -0,0 +1,15 @@
+try {Import-Module $PSScriptRoot\..\..\ImportExcel.psd1} catch {throw ; return}
+
+$r = Get-ChildItem C:\WINDOWS\system32 -File
+
+$TotalSettings = @{ 
+    Length = "Sum"
+    Name = "Count"
+    Extension = @{
+        # You can create the formula in an Excel workbook first and copy-paste it here
+        # This syntax can only be used for the Custom type
+        Custom = "=COUNTIF([Extension];`".exe`")"
+    }
+}
+
+$r | Export-Excel -TableName system32files -TableStyle Medium10 -TotalSettings $TotalSettings -Show
\ No newline at end of file
diff --git a/Public/Add-ExcelTable.ps1 b/Public/Add-ExcelTable.ps1
index 5cb25ec..5a179a8 100644
--- a/Public/Add-ExcelTable.ps1
+++ b/Public/Add-ExcelTable.ps1
@@ -55,6 +55,31 @@ function Add-ExcelTable {
             $tbl.ShowTotal = $true
             foreach ($k in $TotalSettings.keys) {
                 if (-not $tbl.Columns[$k]) {Write-Warning -Message "Table does not have a Column '$k'."}
+                elseif ($TotalSettings[$k] -is [HashTable] -and $TotalSettings[$k].Keys.Count -eq 1 -and $TotalSettings[$k].Keys[0] -eq "Custom") {
+                    $formula = $TotalSettings[$k][($TotalSettings[$k].Keys[0])] | Select -First 1
+                    ### A function in Excel uses ";" between parameters but the OpenXML parameter separator is ","
+                    ### Only replace semicolon when it's NOT somewhere between quotes quotes. 
+                    # Get all text between quotes
+                    $QuoteMatches = [Regex]::Matches($formula,"`"[^`"]*`"|'[^']*'") 
+                    # Create array with all indexes of characters between quotes (and the quotes themselves)
+                    $QuoteCharIndexes = $(
+                        Foreach ($QuoteMatch in $QuoteMatches) {
+                            (($QuoteMatch.Index)..($QuoteMatch.Index + $QuoteMatch.Length - 1))
+                        }
+                    )
+
+                    # Get all semicolons
+                    $SemiColonMatches = [Regex]::Matches($formula, ";")
+                    # Replace the semicolons of which the index is not in the list of quote-text indexes
+                    Foreach ($SemiColonMatch in $SemiColonMatches.Index) {
+                        If ($QuoteCharIndexes -notcontains $SemiColonMatch) {
+                            $formula = $formula.remove($SemiColonMatch,1).Insert($SemiColonMatch,",")
+                        }
+                    }
+
+                    # Configure the formula. The TotalsRowFunction is automatically set to "Custom" when the TotalsRowFormula is set.
+                    $tbl.Columns[$k].TotalsRowFormula = $formula
+                }
                 elseif ($TotalSettings[$k] -notin @("Average", "Count", "CountNums", "Max", "Min", "None", "StdDev", "Sum", "Var") ) {
                     Write-Warning -Message "'$($TotalSettings[$k])' is not a valid total function."
                 }
diff --git a/__tests__/Export-Excel.Tests.ps1 b/__tests__/Export-Excel.Tests.ps1
index 7dc4582..e1c8be1 100644
--- a/__tests__/Export-Excel.Tests.ps1
+++ b/__tests__/Export-Excel.Tests.ps1
@@ -696,6 +696,9 @@ Describe ExportExcel -Tag "ExportExcel" {
                 Id         = "COUNT"
                 WS         = "SUM"
                 Handles    = "AVERAGE"
+                CPU        = @{
+                    Custom = '=COUNTIF([CPU];"<1")'
+                }
             }
             $Processes | Export-Excel $path -TableName "processes" -TotalSettings $TotalSettings
             $TotalRows = $Processes.count + 2 # Column header + Data (50 processes) + Totals row
@@ -708,22 +711,27 @@ Describe ExportExcel -Tag "ExportExcel" {
             $ws.tables[0].ShowTotal                                             | Should -Be $True
         }
         
-        it "Added three calculations in the totals row".PadRight(87) {
+        it "Added four calculations in the totals row".PadRight(87) {
             $IDcolumn = $ws.Tables[0].Columns | Where-Object { $_.Name -eq "id" }
             $WScolumn = $ws.Tables[0].Columns | Where-Object { $_.Name -eq "WS" }
             $HandlesColumn = $ws.Tables[0].Columns | Where-Object { $_.Name -eq "Handles" }
+            $CPUColumn = $ws.Tables[0].Columns | Where-Object { $_.Name -eq "CPU" }
 
             $IDcolumn      | Select-Object -ExpandProperty TotalsRowFunction    | Should -Be "Count"
             $WScolumn      | Select-Object -ExpandProperty TotalsRowFunction    | Should -Be "Sum"
             $HandlesColumn | Select-Object -ExpandProperty TotalsRowFunction    | Should -Be "Average"
+            $CPUColumn     | Select-Object -ExpandProperty TotalsRowFunction    | Should -Be "Custom"
+            $CPUColumn     | Select-Object -ExpandProperty TotalsRowFormula     | Should -Be 'COUNTIF([CPU],"<1")'
 
             $CountAddress = "{0}{1}" -f (Get-ExcelColumnName -ColumnNumber $IDcolumn.Id).ColumnName, $TotalRows
             $SumAddress = "{0}{1}" -f (Get-ExcelColumnName -ColumnNumber $WScolumn.Id).ColumnName, $TotalRows
             $AverageAddress = "{0}{1}" -f (Get-ExcelColumnName -ColumnNumber $HandlesColumn.Id).ColumnName, $TotalRows
+            $CustomAddress = "{0}{1}" -f (Get-ExcelColumnName -ColumnNumber $CPUColumn.Id).ColumnName, $TotalRows
 
             $ws.Cells[$CountAddress].Formula                                    | Should -Be "SUBTOTAL(103,processes[Id])"
             $ws.Cells[$SumAddress].Formula                                      | Should -Be "SUBTOTAL(109,processes[Ws])"
             $ws.Cells[$AverageAddress].Formula                                  | Should -Be "SUBTOTAL(101,processes[Handles])"
+            $ws.Cells[$CustomAddress].Formula                                   | Should -Be 'COUNTIF([CPU],"<1")'
         }
 
         AfterEach {