diff --git a/src/common/sstream.c b/src/common/sstream.c
index 336a65cb..b3122897 100644
--- a/src/common/sstream.c
+++ b/src/common/sstream.c
@@ -54,9 +54,9 @@ void c11_sbuf__write_f64(c11_sbuf* self, double val, int precision) {
     char b[32];
     int size;
     if(precision < 0) {
-        size = snprintf(b, sizeof(b), "%.*g", 15, val);
-        if(strtod(b, NULL) != val) {
-            size = snprintf(b, sizeof(b), "%.*g", 17, val);
+        for(int g = 15; g <= 17; g++) {
+            size = snprintf(b, sizeof(b), "%.*g", g, val);
+            if(strtod(b, NULL) == val) break;
         }
         c11_sbuf__write_cstr(self, b);
         bool all_is_digit = true;
diff --git a/tests/250_rfstring.py b/tests/250_rfstring.py
index d2f93ed8..5381e053 100644
--- a/tests/250_rfstring.py
+++ b/tests/250_rfstring.py
@@ -65,6 +65,7 @@ assert f'{a:010.2f}' == '0000010.00'
 assert f'{a:.2f}' == '10.00'
 assert f'{a:.5f}' == '10.00000'
 assert f'{2.5:.0f}' == '2'
+assert '{:.0f}'.format(2.5) == '2'
 
 b = '123'
 assert f'{b:10}' == '123       '
@@ -140,4 +141,10 @@ assert f'{A():10}' == 'A         '
 assert f'{A():10}' == 'A         '
 
 a = ['1', '2', '3']
-assert f'a = {'\n'.join(a)}' == 'a = 1\n2\n3'
\ No newline at end of file
+assert f'a = {'\n'.join(a)}' == 'a = 1\n2\n3'
+
+assert str(0.1+0.2) == '0.30000000000000004'
+assert str(1/2) == '0.5'
+assert str(1/3) == '0.3333333333333333'
+assert str(1/4) == '0.25'
+assert str(1/7) == '0.14285714285714285'