diff --git a/arm9/source/fileOperations.cpp b/arm9/source/fileOperations.cpp
index 428c236..7ebe039 100644
--- a/arm9/source/fileOperations.cpp
+++ b/arm9/source/fileOperations.cpp
@@ -8,6 +8,7 @@
 #include "date.h"
 #include "file_browse.h"
 #include "font.h"
+#include "ndsheaderbanner.h"
 
 #define copyBufSize 0x8000
 #define shaChunkSize 0x10000
@@ -105,6 +106,25 @@ bool calculateSHA1(const char *fileName, u8 *sha1) {
 	return true;
 }
 
+int trimNds(const char *fileName) {
+	FILE *file = fopen(fileName, "rb");
+	if(file) {
+		sNDSHeaderExt ndsCardHeader;
+
+		fread(&ndsCardHeader, 1, sizeof(ndsCardHeader), file);
+		fclose(file);
+
+		u32 romSize = ((ndsCardHeader.unitCode != 0) && (ndsCardHeader.twlRomSize > 0))
+						? ndsCardHeader.twlRomSize : ndsCardHeader.romSize + 0x88;
+
+		truncate(fileName, romSize);
+
+		return romSize;
+	}
+
+	return -1;
+}
+
 void dirCopy(const DirEntry &entry, int i, const char *destinationPath, const char *sourcePath) {
 	std::vector<DirEntry> dirContents;
 	dirContents.clear();
diff --git a/arm9/source/fileOperations.h b/arm9/source/fileOperations.h
index c07647f..b7c5d49 100644
--- a/arm9/source/fileOperations.h
+++ b/arm9/source/fileOperations.h
@@ -23,6 +23,7 @@ extern std::string getBytes(int bytes);
 
 extern off_t getFileSize(const char *fileName);
 extern bool calculateSHA1(const char *fileName, u8 *sha1);
+extern int trimNds(const char *fileName);
 extern int fcopy(const char *sourcePath, const char *destinationPath);
 void changeFileAttribs(const DirEntry *entry);
 
diff --git a/arm9/source/file_browse.cpp b/arm9/source/file_browse.cpp
index 7333d3f..7e4ed2c 100644
--- a/arm9/source/file_browse.cpp
+++ b/arm9/source/file_browse.cpp
@@ -191,6 +191,7 @@ FileOperation fileBrowse_A(DirEntry* entry, char path[PATH_MAX]) {
 		if(extension(entry->name, {"nds", "dsi", "ids", "app"})) {
 			operations.push_back(FileOperation::mountNitroFS);
 			operations.push_back(FileOperation::ndsInfo);
+			operations.push_back(FileOperation::trimNds);
 		} else if(extension(entry->name, {"sav", "sav1", "sav2", "sav3", "sav4", "sav5", "sav6", "sav7", "sav8", "sav9"})) {
 			operations.push_back(FileOperation::restoreSave);
 		} else if(extension(entry->name, {"img", "sd"})) {
@@ -236,6 +237,9 @@ FileOperation fileBrowse_A(DirEntry* entry, char path[PATH_MAX]) {
 				case FileOperation::ndsInfo:
 					font->print(3, row++, false, "Show NDS file info");
 					break;
+				case FileOperation::trimNds:
+					font->print(3, row++, false, "Trim NDS file");
+					break;
 				case FileOperation::restoreSave:
 					font->print(3, row++, false, "Restore save");
 					break;
@@ -380,6 +384,9 @@ FileOperation fileBrowse_A(DirEntry* entry, char path[PATH_MAX]) {
 				} case FileOperation::ndsInfo: {
 					ndsInfo(entry->name.c_str());
 					break;
+				} case FileOperation::trimNds: {
+					entry->size = trimNds(entry->name.c_str());
+					break;
 				} case FileOperation::showInfo: {
 					changeFileAttribs(entry);
 					break;
diff --git a/arm9/source/file_browse.h b/arm9/source/file_browse.h
index a7deb72..a4c83cd 100644
--- a/arm9/source/file_browse.h
+++ b/arm9/source/file_browse.h
@@ -38,6 +38,8 @@ enum class FileOperation {
 	bootFile,
 	bootstrapFile,
 	mountNitroFS,
+	ndsInfo,
+	trimNds,
 	mountImg,
 	restoreSave,
 	showInfo,
@@ -45,7 +47,6 @@ enum class FileOperation {
 	copyFatOut,
 	calculateSHA1,
 	hexEdit,
-	ndsInfo,
 };
 
 bool extension(const std::string &filename, const std::vector<std::string> &extensions);