diff --git a/wpimath/src/main/native/include/units/base.h b/wpimath/src/main/native/include/units/base.h
index 1900abf28c..b0ae1b89b3 100644
--- a/wpimath/src/main/native/include/units/base.h
+++ b/wpimath/src/main/native/include/units/base.h
@@ -75,7 +75,8 @@
 	#include <iostream>
 	#include <locale>
 	#include <string>
-#else
+#endif
+#if !defined(UNIT_LIB_DISABLE_FMT)
 	#include <locale>
 	#include <string>
 	#include <fmt/format.h>
@@ -175,7 +176,7 @@ namespace units
  * @param		abbrev - abbreviated unit name, e.g. 'm'
  * @note		When UNIT_LIB_ENABLE_IOSTREAM isn't defined, the macro does not generate any code
  */
-#if !defined(UNIT_LIB_ENABLE_IOSTREAM)
+#if !defined(UNIT_LIB_DISABLE_FMT)
 	#define UNIT_ADD_IO(namespaceName, nameSingular, abbrev)\
 	}\
 	template <>\
@@ -200,7 +201,8 @@ namespace units
 			return units::detail::to_string(obj()) + std::string(" "#abbrev);\
 		}\
 	}
-#else
+#endif
+#if defined(UNIT_LIB_ENABLE_IOSTREAM)
 	#define UNIT_ADD_IO(namespaceName, nameSingular, abbrev)\
 	namespace namespaceName\
 	{\
@@ -2864,13 +2866,15 @@ namespace units
 	namespace dimensionless
 	{
 		typedef unit_t<scalar, UNIT_LIB_DEFAULT_TYPE, decibel_scale> dB_t;
-#if defined(UNIT_LIB_ENABLE_IOSTREAM)
-		inline std::ostream& operator<<(std::ostream& os, const dB_t& obj) { os << obj() << " dB"; return os; }
 		typedef dB_t dBi_t;
 	}
-#else
-}
+#if defined(UNIT_LIB_ENABLE_IOSTREAM)
+	namespace dimensionless
+		inline std::ostream& operator<<(std::ostream& os, const dB_t& obj) { os << obj() << " dB"; return os; }
+	}
+#endif
 }
+#if !defined(UNIT_LIB_DISABLE_FMT)
 template <>
 struct fmt::formatter<units::dimensionless::dB_t> : fmt::formatter<double>
 {
@@ -2883,13 +2887,9 @@ struct fmt::formatter<units::dimensionless::dB_t> : fmt::formatter<double>
 		return fmt::format_to(out, " dB");
 	}
 };
-
-namespace units {
-namespace dimensionless {
-		typedef dB_t dBi_t;
-	}
 #endif
 
+namespace units {
 	//------------------------------
 	//	DECIBEL ARITHMETIC
 	//------------------------------
@@ -3439,4 +3439,6 @@ namespace units::literals {}
 using namespace units::literals;
 #endif  // UNIT_HAS_LITERAL_SUPPORT
 
+#if !defined(UNIT_LIB_DISABLE_FMT)
 #include "frc/fmt/Units.h"
+#endif
diff --git a/wpimath/src/test/native/cpp/UnitsTest.cpp b/wpimath/src/test/native/cpp/UnitsTest.cpp
index 6f70d83a7e..1059260f05 100644
--- a/wpimath/src/test/native/cpp/UnitsTest.cpp
+++ b/wpimath/src/test/native/cpp/UnitsTest.cpp
@@ -1420,6 +1420,7 @@ TEST_F(UnitContainer, cout) {
 }
 #endif
 
+#if !defined(UNIT_LIB_DISABLE_FMT)
 TEST_F(UnitContainer, fmtlib) {
   testing::internal::CaptureStdout();
   fmt::print("{}", degree_t(349.87));
@@ -1500,6 +1501,7 @@ TEST_F(UnitContainer, fmtlib) {
   EXPECT_STREQ("5.670367e-08 kg s^-3 K^-4", output.c_str());
 #endif
 }
+#endif
 
 TEST_F(UnitContainer, to_string) {
   foot_t a(3.5);