diff --git a/to_string.hpp b/to_string.hpp
index 3f04272..e7eef93 100644
--- a/to_string.hpp
+++ b/to_string.hpp
@@ -15,7 +15,7 @@
  * @tparam N Number to convert
  * @tparam base Desired base, can be from 2 to 36
  */
-template<auto N, unsigned int base, typename char_type,
+template<auto N, int base, typename char_type,
     std::enable_if_t<std::is_integral_v<decltype(N)>, int> = 0,
     std::enable_if_t<(base > 1 && base < 37), int> = 0>
 class to_string_t {
@@ -23,7 +23,7 @@ class to_string_t {
     // fits to the number perfectly.
     char_type buf[([]() constexpr noexcept {
                        unsigned int len = N > 0 ? 1 : 2;
-                       for (auto n = N < 0 ? -N : N; n; len++, n /= base);
+                       for (auto n = N; n; len++, n /= base);
                        return len;
                    }())] = {};
 
@@ -35,8 +35,8 @@ class to_string_t {
         auto ptr = end();
         *--ptr = '\0';
         if (N != 0) {
-            for (auto n = N < 0 ? -N : N; n; n /= base)
-                *--ptr = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ"[n % base];
+            for (auto n = N; n; n /= base)
+                *--ptr = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ"[(N < 0 ? -1 : 1) * (n % base)];
             if (N < 0)
                 *--ptr = '-';
         } else {