diff --git a/clib.json b/clib.json
index ded5b77..8ef6699 100644
--- a/clib.json
+++ b/clib.json
@@ -1,6 +1,6 @@
 {
   "name": "libutil",
-  "version": "0.0.13",
+  "version": "0.1.13",
   "author": "Matthew Zito",
   "repo": "exbotanical/libutil",
   "license": "MIT",
diff --git a/include/libutil.h b/include/libutil.h
index a71fd39..fdc8a22 100644
--- a/include/libutil.h
+++ b/include/libutil.h
@@ -229,7 +229,7 @@ void buffer_free(buffer_t *buf);
 /**
  * Returns a formatted string. Uses printf syntax.
  */
-char *fmt_str(char *fmt, ...);
+char *s_fmt(char *fmt, ...);
 
 /**
  * s_truncate truncates the given string `s` by `n` characters.
diff --git a/src/fmt.c b/src/fmt.c
deleted file mode 100644
index 040b945..0000000
--- a/src/fmt.c
+++ /dev/null
@@ -1,25 +0,0 @@
-#include <stdarg.h>
-#include <stdio.h>
-#include <stdlib.h>
-
-#include "libutil.h"
-
-char *fmt_str(char *fmt, ...) {
-  va_list args, args_cp;
-  va_start(args, fmt);
-  va_copy(args_cp, args);
-
-  // Pass length of zero first to determine number of bytes needed
-  unsigned int n = vsnprintf(NULL, 0, fmt, args) + 1;
-  char *buf = malloc(n);
-  if (!buf) {
-    return NULL;
-  }
-
-  vsnprintf(buf, n, fmt, args_cp);
-
-  va_end(args);
-  va_end(args_cp);
-
-  return buf;
-}
diff --git a/src/str.c b/src/str.c
index dcac53c..8a7312a 100644
--- a/src/str.c
+++ b/src/str.c
@@ -1,4 +1,5 @@
 #include <ctype.h>  // for toupper
+#include <stdarg.h>
 #include <stdio.h>  // for snprintf
 #include <stdlib.h>
 #include <string.h>
@@ -212,3 +213,23 @@ array_t *s_split(const char *s, const char *delim) {
 
   return tokens;
 }
+
+char *s_fmt(char *fmt, ...) {
+  va_list args, args_cp;
+  va_start(args, fmt);
+  va_copy(args_cp, args);
+
+  // Pass length of zero first to determine number of bytes needed
+  unsigned int n = vsnprintf(NULL, 0, fmt, args) + 1;
+  char *buf = malloc(n);
+  if (!buf) {
+    return NULL;
+  }
+
+  vsnprintf(buf, n, fmt, args_cp);
+
+  va_end(args);
+  va_end(args_cp);
+
+  return buf;
+}
diff --git a/t/fmt_test.c b/t/fmt_test.c
deleted file mode 100644
index 776fdd1..0000000
--- a/t/fmt_test.c
+++ /dev/null
@@ -1,12 +0,0 @@
-#include "libutil.h"
-#include "tap.c/tap.h"
-#include "tests.h"
-
-void test_fmt_str(void) {
-  char *formatted = fmt_str("%s %d %s", "test", 11, "string");
-  is(formatted, "test 11 string", "formats each part into a single string");
-
-  free(formatted);
-}
-
-void run_fmt_tests(void) { test_fmt_str(); }
diff --git a/t/main.c b/t/main.c
index fe0096b..3f30e47 100644
--- a/t/main.c
+++ b/t/main.c
@@ -6,7 +6,6 @@ int main() {
 
   run_array_tests();
   run_buffer_tests();
-  run_fmt_tests();
   run_str_tests();
 
   done_testing();
diff --git a/t/str_test.c b/t/str_test.c
index f7ee703..c3d485d 100644
--- a/t/str_test.c
+++ b/t/str_test.c
@@ -290,6 +290,13 @@ void test_s_split_end_match(void) {
   array_free_ptrs(paths);
 }
 
+void test_s_fmt(void) {
+  char *formatted = s_fmt("%s %d %s", "test", 11, "string");
+  is(formatted, "test 11 string", "formats each part into a single string");
+
+  free(formatted);
+}
+
 void run_str_tests(void) {
   test_s_copy();
 
@@ -325,4 +332,6 @@ void run_str_tests(void) {
   test_s_split_no_match();
   test_s_split_empty_input();
   test_s_split_end_match();
+
+  test_s_fmt();
 }
diff --git a/t/tests.h b/t/tests.h
index eb05599..1700852 100644
--- a/t/tests.h
+++ b/t/tests.h
@@ -3,7 +3,6 @@
 
 void run_array_tests(void);
 void run_buffer_tests(void);
-void run_fmt_tests(void);
 void run_str_tests(void);
 
 #endif /* TESTS_H */