diff --git a/firmware/application/file.cpp b/firmware/application/file.cpp
index 18e75005..7c73a729 100644
--- a/firmware/application/file.cpp
+++ b/firmware/application/file.cpp
@@ -164,5 +164,23 @@ bool is_regular_file(const file_status s) {
 	return !(s & AM_DIR);
 }
 
+space_info space(const path& p) {
+	DWORD free_clusters { 0 };
+	FATFS* fs;
+	if( f_getfree(p.c_str(), &free_clusters, &fs) == FR_OK ) {
+#if _MAX_SS != _MIN_SS
+		static_assert(false, "FatFs not configured for fixed sector size");
+#else
+		return {
+			(fs->n_fatent - 2) * fs->csize * _MIN_SS,
+			free_clusters * fs->csize * _MIN_SS,
+			free_clusters * fs->csize * _MIN_SS,
+		};
+#endif
+	} else {
+		return { 0, 0, 0 };
+	}
+}
+
 } /* namespace filesystem */
 } /* namespace std */
diff --git a/firmware/application/file.hpp b/firmware/application/file.hpp
index 6be0f9dd..fde40db2 100644
--- a/firmware/application/file.hpp
+++ b/firmware/application/file.hpp
@@ -25,6 +25,7 @@
 #include "ff.h"
 
 #include <cstddef>
+#include <cstdint>
 #include <string>
 #include <array>
 #include <memory>
@@ -75,8 +76,17 @@ std::string next_filename_stem_matching_pattern(const std::string& filename_stem
 namespace std {
 namespace filesystem {
 
+using path = std::string;
 using file_status = BYTE;
 
+struct space_info {
+	static_assert(sizeof(std::uintmax_t) >= 8, "std::uintmax_t too small (<uint64_t)");
+
+	std::uintmax_t capacity;
+	std::uintmax_t free;
+	std::uintmax_t available;
+};
+
 struct directory_entry : public FILINFO {
 	file_status status() const {
 		return fattrib;
@@ -126,6 +136,8 @@ inline bool operator!=(const directory_iterator& lhs, const directory_iterator&
 
 bool is_regular_file(const file_status s);
 
+space_info space(const path& p);
+
 } /* namespace filesystem */
 } /* namespace std */