diff --git a/sys/arm/include/_stdint.h b/sys/arm/include/_stdint.h
--- a/sys/arm/include/_stdint.h
+++ b/sys/arm/include/_stdint.h
@@ -153,6 +153,29 @@
 #define	WINT_MIN	INT32_MIN
 #define	WINT_MAX	INT32_MAX
 
+#if __ISO_C_VISIBLE >= 2023
+/*
+ * ISO/IEC 9899:2023
+ * 7.22.2 Widths of specified-width integer types
+ */
+#define INT_FAST8_WIDTH		INT32_WIDTH
+#define INT_FAST16_WIDTH	INT32_WIDTH
+#define INT_FAST32_WIDTH	INT32_WIDTH
+#define INT_FAST64_WIDTH	INT64_WIDTH
+#define INTPTR_WIDTH		INT32_WIDTH
+#define INTMAX_WIDTH		INT64_WIDTH
+
+/*
+ * ISO/IEC 9899:2023
+ * 7.22.3 Width of other integer types
+ */
+#define PTRDIFF_WIDTH		INT32_WIDTH
+#define SIG_ATOMIC_WIDTH	INT32_WIDTH
+#define SIZE_WIDTH		INT32_WIDTH
+#define WCHAR_WIDTH		INT32_WIDTH
+#define WINT_WIDTH		INT32_WIDTH
+#endif /* __ISO_C_VISIBLE >= 2023 */
+
 #endif /* !defined(__cplusplus) || defined(__STDC_LIMIT_MACROS) */
 
 #endif /* !_MACHINE__STDINT_H_ */
diff --git a/sys/arm64/include/_stdint.h b/sys/arm64/include/_stdint.h
--- a/sys/arm64/include/_stdint.h
+++ b/sys/arm64/include/_stdint.h
@@ -155,6 +155,29 @@
 #define	WINT_MIN	INT32_MIN
 #define	WINT_MAX	INT32_MAX
 
+#if __ISO_C_VISIBLE >= 2023
+/*
+ * ISO/IEC 9899:2023
+ * 7.22.2 Widths of specified-width integer types
+ */
+#define INT_FAST8_WIDTH         INT32_WIDTH
+#define INT_FAST16_WIDTH        INT32_WIDTH
+#define INT_FAST32_WIDTH        INT32_WIDTH
+#define INT_FAST64_WIDTH        INT64_WIDTH
+#define INTPTR_WIDTH            INT64_WIDTH
+#define INTMAX_WIDTH            INT64_WIDTH
+
+/*
+ * ISO/IEC 9899:2023
+ * 7.22.3 Width of other integer types
+ */
+#define PTRDIFF_WIDTH           INT64_WIDTH
+#define SIG_ATOMIC_WIDTH        INT64_WIDTH
+#define SIZE_WIDTH              INT64_WIDTH
+#define WCHAR_WIDTH             INT32_WIDTH
+#define WINT_WIDTH              INT32_WIDTH
+#endif /* __ISO_C_VISIBLE >= 2023 */
+
 #endif /* !defined(__cplusplus) || defined(__STDC_LIMIT_MACROS) */
 
 #endif /* !_MACHINE__STDINT_H_ */
diff --git a/sys/powerpc/include/_stdint.h b/sys/powerpc/include/_stdint.h
--- a/sys/powerpc/include/_stdint.h
+++ b/sys/powerpc/include/_stdint.h
@@ -195,6 +195,39 @@
 #define	WINT_MIN	INT32_MIN
 #define	WINT_MAX	INT32_MAX
 
+#if __ISO_C_VISIBLE >= 2023
+/*
+ * ISO/IEC 9899:2023
+ * 7.22.2 Widths of specified-width integer types
+ */
+#define INT_FAST8_WIDTH		INT32_WIDTH
+#define INT_FAST16_WIDTH	INT32_WIDTH
+#define INT_FAST32_WIDTH	INT32_WIDTH
+#define INT_FAST64_WIDTH	INT64_WIDTH
+#ifdef __LP64__
+#define INTPTR_WIDTH		INT64_WIDTH
+#else
+#define INTPTR_WIDTH		INT32_WIDTH
+#endif
+#define INTMAX_WIDTH		INT64_WIDTH
+
+/*
+ * ISO/IEC 9899:2023
+ * 7.22.3 Width of other integer types
+ */
+#ifdef	__LP64__
+#define PTRDIFF_WIDTH		INT64_WIDTH
+#define SIG_ATOMIC_WIDTH	INT64_WIDTH
+#define SIZE_WIDTH		INT64_WIDTH
+#else
+#define PTRDIFF_WIDTH		INT32_WIDTH
+#define SIG_ATOMIC_WIDTH	INT32_WIDTH
+#define SIZE_WIDTH		INT32_WIDTH
+#endif
+#define WCHAR_WIDTH		INT32_WIDTH
+#define WINT_WIDTH		INT32_WIDTH
+#endif /* __ISO_C_VISIBLE >= 2023 */
+
 #endif /* !defined(__cplusplus) || defined(__STDC_LIMIT_MACROS) */
 
 #endif /* !_MACHINE__STDINT_H_ */
diff --git a/sys/riscv/include/_stdint.h b/sys/riscv/include/_stdint.h
--- a/sys/riscv/include/_stdint.h
+++ b/sys/riscv/include/_stdint.h
@@ -151,6 +151,29 @@
 #define	WINT_MIN	INT32_MIN
 #define	WINT_MAX	INT32_MAX
 
+#if __ISO_C_VISIBLE >= 2023
+/*
+ * ISO/IEC 9899:2023
+ * 7.22.2 Widths of specified-width integer types
+ */
+#define INT_FAST8_WIDTH		INT32_WIDTH
+#define INT_FAST16_WIDTH	INT32_WIDTH
+#define INT_FAST32_WIDTH	INT32_WIDTH
+#define INT_FAST64_WIDTH	INT64_WIDTH
+#define INTPTR_WIDTH		INT64_WIDTH
+#define INTMAX_WIDTH		INT64_WIDTH
+
+/*
+ * ISO/IEC 9899:2023
+ * 7.22.3 Width of other integer types
+ */
+#define PTRDIFF_WIDTH		INT64_WIDTH
+#define SIG_ATOMIC_WIDTH	INT64_WIDTH
+#define SIZE_WIDTH		INT64_WIDTH
+#define WCHAR_WIDTH		INT32_WIDTH
+#define WINT_WIDTH		INT32_WIDTH
+#endif /* __ISO_C_VISIBLE >= 2023 */
+
 #endif /* !defined(__cplusplus) || defined(__STDC_LIMIT_MACROS) */
 
 #endif /* !_MACHINE__STDINT_H_ */
diff --git a/sys/sys/stdint.h b/sys/sys/stdint.h
--- a/sys/sys/stdint.h
+++ b/sys/sys/stdint.h
@@ -73,4 +73,33 @@
 #endif
 #endif /* __EXT1_VISIBLE */
 
+#if __ISO_C_VISIBLE >= 2023
+#define INT8_WIDTH		8
+#define UINT8_WIDTH		8
+#define INT_LEAST8_WIDTH	8
+#define UINT_LEAST8_WIDTH	8
+#define UINT_FAST8_WIDTH	INT_FAST8_WIDTH
+
+#define INT16_WIDTH		16
+#define UINT16_WIDTH		16
+#define INT_LEAST16_WIDTH	16
+#define UINT_LEAST16_WIDTH	16
+#define UINT_FAST16_WIDTH	INT_FAST16_WIDTH
+
+#define INT32_WIDTH		32
+#define UINT32_WIDTH		32
+#define INT_LEAST32_WIDTH	32
+#define UINT_LEAST32_WIDTH	32
+#define UINT_FAST32_WIDTH	INT_FAST32_WIDTH
+
+#define INT64_WIDTH		64
+#define UINT64_WIDTH		64
+#define INT_LEAST64_WIDTH	64
+#define UINT_LEAST64_WIDTH	64
+#define UINT_FAST64_WIDTH	INT_FAST64_WIDTH
+
+#define	UINTMAX_WIDTH		INTMAX_WIDTH
+#define	UINTPTR_WIDTH		INTPTR_WIDTH
+#endif /* __ISO_C_VISIBLE >= 2023 */
+
 #endif /* !_SYS_STDINT_H_ */
diff --git a/sys/x86/include/_stdint.h b/sys/x86/include/_stdint.h
--- a/sys/x86/include/_stdint.h
+++ b/sys/x86/include/_stdint.h
@@ -184,6 +184,39 @@
 #define	WINT_MIN	INT32_MIN
 #define	WINT_MAX	INT32_MAX
 
+#if __ISO_C_VISIBLE >= 2023
+/*
+ * ISO/IEC 9899:2023
+ * 7.22.2 Widths of specified-width integer types
+ */
+#define INT_FAST8_WIDTH		INT32_WIDTH
+#define INT_FAST16_WIDTH	INT32_WIDTH
+#define INT_FAST32_WIDTH	INT32_WIDTH
+#define INT_FAST64_WIDTH	INT64_WIDTH
+#ifdef __LP64__
+#define INTPTR_WIDTH		INT64_WIDTH
+#else
+#define INTPTR_WIDTH		INT32_WIDTH
+#endif
+#define INTMAX_WIDTH		INT64_WIDTH
+
+/*
+ * ISO/IEC 9899:2023
+ * 7.22.3 Width of other integer types
+ */
+#ifdef	__LP64__
+#define PTRDIFF_WIDTH		INT64_WIDTH
+#define SIG_ATOMIC_WIDTH	INT64_WIDTH
+#define SIZE_WIDTH		INT64_WIDTH
+#else
+#define PTRDIFF_WIDTH		INT32_WIDTH
+#define SIG_ATOMIC_WIDTH	INT32_WIDTH
+#define SIZE_WIDTH		INT32_WIDTH
+#endif
+#define WCHAR_WIDTH		INT32_WIDTH
+#define WINT_WIDTH		INT32_WIDTH
+#endif /* __ISO_C_VISIBLE >= 2023 */
+
 #endif /* !defined(__cplusplus) || defined(__STDC_LIMIT_MACROS) */
 
 #endif /* !_MACHINE__STDINT_H_ */