diff --git a/src/r_defs.h b/src/r_defs.h
index 121a17dc0..eac3e2d1f 100644
--- a/src/r_defs.h
+++ b/src/r_defs.h
@@ -910,10 +910,6 @@ typedef struct
 #pragma pack()
 #endif
 
-#define MAX_PATCH_DIMENSIONS 8192
-
-#define VALID_PATCH_LUMP_SIZE(lumplen, width) ((lumplen) >= (sizeof(INT16) * 4) + ((width) * sizeof(INT32)))
-
 // Possible alpha types for a patch.
 enum patchalphastyle {AST_COPY, AST_TRANSLUCENT, AST_ADD, AST_SUBTRACT, AST_REVERSESUBTRACT, AST_MODULATE, AST_OVERLAY, AST_FOG};
 
diff --git a/src/r_picformats.c b/src/r_picformats.c
index 56db44975..be4e03120 100644
--- a/src/r_picformats.c
+++ b/src/r_picformats.c
@@ -812,7 +812,7 @@ boolean Picture_IsFlatFormat(pictureformat_t format)
 boolean Picture_CheckIfDoomPatch(softwarepatch_t *patch, size_t size)
 {
 	// Does not meet minimum size requirements
-	if (size < PATCH_MIN_SIZE)
+	if (size < MIN_PATCH_LUMP_SIZE)
 		return false;
 
 	INT16 width = SHORT(patch->width);
@@ -835,7 +835,7 @@ boolean Picture_CheckIfDoomPatch(softwarepatch_t *patch, size_t size)
 		UINT32 ofs = LONG(patch->columnofs[x]);
 
 		// Need one byte for an empty column (but there's patches that don't know that!)
-		if (ofs < ((sizeof(INT16) * 4) + (width * sizeof(INT32))) || ofs >= (UINT32)size)
+		if (ofs < FIRST_PATCH_LUMP_COLUMN(width) || (size_t)ofs >= size)
 		{
 			return false;
 		}
diff --git a/src/r_picformats.h b/src/r_picformats.h
index ac6fc2992..b1e957b10 100644
--- a/src/r_picformats.h
+++ b/src/r_picformats.h
@@ -55,9 +55,21 @@ enum
 	PICDEPTH_32BPP = 32
 };
 
-// Minimum length of a valid Doom patch
+// Maximum allowed dimensions for a patch
+#define MAX_PATCH_DIMENSIONS 8192
+
+// Minimum amount of bytes required for a valid patch lump header
+#define MIN_PATCH_LUMP_HEADER_SIZE ((sizeof(INT16) * 4) + sizeof(INT32))
+
+// Minimum length of a valid Doom patch lump
 // This is the size of a 1x1 patch.
-#define PATCH_MIN_SIZE ((sizeof(INT16) * 4) + (sizeof(INT32)) + 1)
+#define MIN_PATCH_LUMP_SIZE (MIN_PATCH_LUMP_HEADER_SIZE + 1)
+
+// Gets the offset to the very first column in a patch lump
+#define FIRST_PATCH_LUMP_COLUMN(width) ((sizeof(INT16) * 4) + ((width) * sizeof(INT32)))
+
+// Checks if the size of a lump is valid for a patch, given a certain width
+#define VALID_PATCH_LUMP_SIZE(lumplen, width) ((lumplen) >= FIRST_PATCH_LUMP_COLUMN(width))
 
 // Minimum size of a PNG file.
 // See: https://web.archive.org/web/20230524232139/http://garethrees.org/2007/11/14/pngcrush/
diff --git a/src/w_wad.c b/src/w_wad.c
index 456b01a1a..f7d880e2b 100644
--- a/src/w_wad.c
+++ b/src/w_wad.c
@@ -1700,7 +1700,7 @@ lumpnum_t W_GetNumForLongName(const char *name)
 // in its entirety.
 static boolean W_IsProbablyValidPatch(UINT16 wadnum, UINT16 lumpnum)
 {
-	UINT8 header[PATCH_MIN_SIZE];
+	UINT8 header[MIN_PATCH_LUMP_HEADER_SIZE];
 
 	I_StaticAssert(sizeof(header) >= PNG_HEADER_SIZE);
 
@@ -1708,7 +1708,7 @@ static boolean W_IsProbablyValidPatch(UINT16 wadnum, UINT16 lumpnum)
 	size_t lumplen = W_LumpLengthPwad(wadnum, lumpnum);
 
 	// Cannot be a valid Doom patch
-	if (lumplen < sizeof(header))
+	if (lumplen < MIN_PATCH_LUMP_SIZE)
 		return false;
 
 	// Check if it's probably a valid PNG
@@ -1726,7 +1726,7 @@ static boolean W_IsProbablyValidPatch(UINT16 wadnum, UINT16 lumpnum)
 		// Otherwise, we read it as a patch
 	}
 
-	// Read the first 12 bytes, plus one
+	// Read the first 12 bytes
 	W_ReadLumpHeaderPwad(wadnum, lumpnum, header, sizeof(header), 0);
 
 	softwarepatch_t patch;
@@ -1746,7 +1746,7 @@ static boolean W_IsProbablyValidPatch(UINT16 wadnum, UINT16 lumpnum)
 		UINT32 ofs = LONG(patch.columnofs[0]);
 
 		// Need one byte for an empty column (but there's patches that don't know that!)
-		if (ofs < ((sizeof(INT16) * 4) + (width * sizeof(INT32))) || ofs >= (UINT32)lumplen)
+		if (ofs < FIRST_PATCH_LUMP_COLUMN(width) || (size_t)ofs >= lumplen)
 		{
 			return false;
 		}