diff --git a/Create-PillarBox.ps1 b/Create-PillarBox.ps1
index 69a95a0..12b1843 100644
--- a/Create-PillarBox.ps1
+++ b/Create-PillarBox.ps1
@@ -5,6 +5,8 @@
     Path to the input video file. Can be absolute or relative to current directory. .mp4 extension is added if not provided.
 .PARAMETER Target
     Path to the output video file. Can be absolute or relative to current directory. .mp4 extension is added if not provided.
+    If omitted, defaults to the source filename with the -Effect value (lowercased) appended after a dash,
+    saved alongside the source (e.g. video.mp4 + -Effect black -> video-black.mp4).
 .PARAMETER Effect
     The effect to apply to the side bars. Possible values are:
     black: The side bars will be black.
@@ -33,8 +35,8 @@ param(
     [Parameter(Mandatory = $true)]
     [string]$Source,
 
-    [Parameter(Mandatory = $true)]
-    [string]$Target,
+    [Parameter(Mandatory = $false)]
+    [string]$Target = $null,
 
     [Parameter(Mandatory = $true)]
     [string]$Effect,
@@ -183,13 +185,17 @@ function Resolve-Size {
     return [pscustomobject]@{ Width = $w; Height = $h }
 }
 
-# Append .mp4 extension if missing
+# Validate -Effect first so it can be used in the default -Target name.
+$validEffects = @('black', 'white', 'standard', 'dark', 'gaussian')
+$effectLower = $Effect.ToLower()
+if ($effectLower -notin $validEffects) {
+    throw "Invalid -Effect value: $Effect. Must be one of: $($validEffects -join ', ')"
+}
+
+# Append .mp4 extension if missing on -Source
 if (-not [System.IO.Path]::GetExtension($Source)) {
     $Source = "$Source.mp4"
 }
-if (-not [System.IO.Path]::GetExtension($Target)) {
-    $Target = "$Target.mp4"
-}
 
 if (-not (Test-Path -LiteralPath $Source)) {
     throw "Source video not found: $Source"
@@ -197,6 +203,17 @@ if (-not (Test-Path -LiteralPath $Source)) {
 
 $sourceFull = (Resolve-Path -LiteralPath $Source).Path
 
+# Default -Target: same directory and base name as -Source, with the effect appended
+# (e.g. C:\clips\video.mp4 + -Effect Black -> C:\clips\video-black.mp4).
+if ([string]::IsNullOrWhiteSpace($Target)) {
+    $srcDir = [System.IO.Path]::GetDirectoryName($sourceFull)
+    $srcBase = [System.IO.Path]::GetFileNameWithoutExtension($sourceFull)
+    $Target = Join-Path $srcDir "$srcBase-$effectLower.mp4"
+}
+elseif (-not [System.IO.Path]::GetExtension($Target)) {
+    $Target = "$Target.mp4"
+}
+
 # Resolve Target to an absolute path (may not exist yet)
 if ([System.IO.Path]::IsPathRooted($Target)) {
     $targetFull = $Target
@@ -219,12 +236,6 @@ if ($CRF -ne -1 -and ($CRF -lt 0 -or $CRF -gt 51)) {
     throw "Invalid -CRF value: $CRF. Must be in range 0-51."
 }
 
-$validEffects = @('black', 'white', 'standard', 'dark', 'gaussian')
-$effectLower = $Effect.ToLower()
-if ($effectLower -notin $validEffects) {
-    throw "Invalid -Effect value: $Effect. Must be one of: $($validEffects -join ', ')"
-}
-
 $inInfo = Get-VideoInfo -Path $sourceFull
 
 $inRes = "{0}x{1}" -f $inInfo.Width, $inInfo.Height