diff --git a/Source/CMakeLists.txt b/Source/CMakeLists.txt
index 3b70daf4f2..61b3695cfe 100644
--- a/Source/CMakeLists.txt
+++ b/Source/CMakeLists.txt
@@ -93,6 +93,12 @@ else()
   if (HAS_STRINGOP_TRUNCATION_WARNING)
     check_and_add_flag(NO_STRINGOP_TRUNCATION -Wno-stringop-truncation)
   endif()
+
+  # Format string issues that the compiler can detect should be compile time errors.
+  check_cxx_compiler_flag(-Wformat HAS_FORMAT_WARNING)
+  if (HAS_FORMAT_WARNING)
+    check_and_add_flag(FORMAT_WARNING_TO_ERROR -Werror=format)
+  endif()
 endif()
 
 # These aren't actually needed for C11/C++11
diff --git a/Source/UnitTests/Core/PowerPC/Jit64Common/ConvertDoubleToSingle.cpp b/Source/UnitTests/Core/PowerPC/Jit64Common/ConvertDoubleToSingle.cpp
index 41ca31b273..aa4324968d 100644
--- a/Source/UnitTests/Core/PowerPC/Jit64Common/ConvertDoubleToSingle.cpp
+++ b/Source/UnitTests/Core/PowerPC/Jit64Common/ConvertDoubleToSingle.cpp
@@ -14,6 +14,7 @@
 #include "Core/PowerPC/Jit64Common/Jit64AsmCommon.h"
 #include "Core/PowerPC/Jit64Common/Jit64PowerPCState.h"
 
+#include <fmt/format.h>
 #include <gtest/gtest.h>
 
 namespace
@@ -109,7 +110,7 @@ TEST(Jit64, ConvertDoubleToSingle)
     const u32 expected = ConvertToSingle(input);
     const u32 actual = routines.wrapped_cdts(input);
 
-    printf("%016llx -> %08x == %08x\n", input, actual, expected);
+    fmt::print("{:016x} -> {:08x} == {:08x}\n", input, actual, expected);
 
     EXPECT_EQ(expected, actual);
   }
diff --git a/Source/UnitTests/Core/PowerPC/Jit64Common/Frsqrte.cpp b/Source/UnitTests/Core/PowerPC/Jit64Common/Frsqrte.cpp
index 18e0ee8044..4dff5ff723 100644
--- a/Source/UnitTests/Core/PowerPC/Jit64Common/Frsqrte.cpp
+++ b/Source/UnitTests/Core/PowerPC/Jit64Common/Frsqrte.cpp
@@ -14,6 +14,7 @@
 #include "Core/PowerPC/Jit64Common/Jit64AsmCommon.h"
 #include "Core/PowerPC/Jit64Common/Jit64PowerPCState.h"
 
+#include <fmt/format.h>
 #include <gtest/gtest.h>
 
 namespace
@@ -98,7 +99,7 @@ TEST(Jit64, Frsqrte)
 
     u64 actual = routines.wrapped_frsqrte(ivalue, fpscr);
 
-    printf("%016llx -> %016llx == %016llx\n", ivalue, actual, expected);
+    fmt::print("{:016x} -> {:016x} == {:016x}\n", ivalue, actual, expected);
 
     EXPECT_EQ(expected, actual);
   }