diff --git a/include/fmt/format.h b/include/fmt/format.h
index 32976ab90f75f..60200e4aeb720 100644
--- a/include/fmt/format.h
+++ b/include/fmt/format.h
@@ -360,6 +360,10 @@ class uint128_fallback {
       -> uint128_fallback {
     return {lhs.hi_ & rhs.hi_, lhs.lo_ & rhs.lo_};
   }
+  friend constexpr auto operator~(const uint128_fallback& n)
+      -> uint128_fallback {
+    return {~n.hi_, ~n.lo_};
+  }
   friend auto operator+(const uint128_fallback& lhs,
                         const uint128_fallback& rhs) -> uint128_fallback {
     auto result = uint128_fallback(lhs);
@@ -398,6 +402,10 @@ class uint128_fallback {
     lo_ = new_lo;
     hi_ = new_hi;
   }
+  FMT_CONSTEXPR void operator&=(uint128_fallback n) {
+    lo_ = lo_ & n.lo_;
+    hi_ = hi_ & n.hi_;
+  }
 
   FMT_CONSTEXPR20 uint128_fallback& operator+=(uint64_t n) noexcept {
     if (is_constant_evaluated()) {