diff --git a/include/fmt/format.h b/include/fmt/format.h
index 0903667c..9ecda111 100644
--- a/include/fmt/format.h
+++ b/include/fmt/format.h
@@ -546,6 +546,7 @@ constexpr auto to_pointer(OutputIt, size_t) -> T* {
 template <typename T> auto to_pointer(basic_appender<T> it, size_t n) -> T* {
   buffer<T>& buf = get_container(it);
   auto size = buf.size();
+  buf.try_reserve(size + n);
   if (buf.capacity() < size + n) return nullptr;
   buf.try_resize(size + n);
   return buf.data() + size;
@@ -2317,15 +2318,13 @@ FMT_CONSTEXPR auto write(OutputIt out, T value) -> OutputIt {
   if (negative) abs_value = ~abs_value + 1;
   int num_digits = count_digits(abs_value);
   auto size = (negative ? 1 : 0) + static_cast<size_t>(num_digits);
-  auto it = reserve(out, size);
-  if (auto ptr = to_pointer<Char>(it, size)) {
+  if (auto ptr = to_pointer<Char>(out, size)) {
     if (negative) *ptr++ = static_cast<Char>('-');
     format_decimal<Char>(ptr, abs_value, num_digits);
     return out;
   }
-  if (negative) *it++ = static_cast<Char>('-');
-  it = format_decimal<Char>(it, abs_value, num_digits).end;
-  return base_iterator(out, it);
+  if (negative) *out++ = static_cast<Char>('-');
+  return format_decimal<Char>(out, abs_value, num_digits).end;
 }
 
 // DEPRECATED!