diff --git a/spa/include/spa/utils/json.h b/spa/include/spa/utils/json.h
index cfa7fc15f..8303d4a3e 100644
--- a/spa/include/spa/utils/json.h
+++ b/spa/include/spa/utils/json.h
@@ -34,9 +34,11 @@ extern "C" {
 #include <stdlib.h>
 #include <stdint.h>
 #include <string.h>
-#include <locale.h>
+#include <math.h>
+#include <float.h>
 
 #include <spa/utils/defs.h>
+#include <spa/utils/string.h>
 
 /** \defgroup spa_json JSON
  * Relaxed JSON variant parsing
@@ -238,13 +240,7 @@ static inline bool spa_json_is_null(const char *val, int len)
 static inline int spa_json_parse_float(const char *val, int len, float *result)
 {
 	char *end;
-	static locale_t locale = NULL;
-	if (SPA_UNLIKELY(locale == NULL))
-		locale = newlocale(LC_ALL_MASK, "C", NULL);
-	if (locale != NULL)
-		*result = strtof_l(val, &end, locale);
-	else
-		*result = strtof(val, &end);
+	*result = spa_strtof(val, &end);
 	return len > 0 && end == val + len;
 }
 
diff --git a/spa/include/spa/utils/string.h b/spa/include/spa/utils/string.h
index 2260bb1cb..d8d68657a 100644
--- a/spa/include/spa/utils/string.h
+++ b/spa/include/spa/utils/string.h
@@ -32,6 +32,8 @@ extern "C" {
 #include <stdarg.h>
 #include <stdbool.h>
 #include <errno.h>
+#include <stdlib.h>
+#include <locale.h>
 
 #include <spa/utils/defs.h>
 
@@ -263,6 +265,27 @@ static inline int spa_scnprintf(char *buffer, size_t size, const char *format, .
 	return r;
 }
 
+/**
+ * Convert \a str to a float in the C locale.
+ *
+ * If \a endptr is not NULL, a pointer to the character after the last character
+ * used in the conversion is stored in the location referenced by endptr.
+ *
+ * \return the result float.
+ */
+static inline float spa_strtof(const char *str, char **endptr)
+{
+	static locale_t locale = NULL;
+	float v;
+	if (SPA_UNLIKELY(locale == NULL))
+		locale = newlocale(LC_ALL_MASK, "C", NULL);
+	if (locale != NULL)
+		v = strtof_l(str, endptr, locale);
+	else
+		v = strtof(str, endptr);
+	return v;
+}
+
 /**
  * Convert \a str to a float and store the result in \a val.
  *
@@ -277,9 +300,8 @@ static inline bool spa_atof(const char *str, float *val)
 
 	if (!str || *str =='\0')
 		return false;
-
 	errno = 0;
-	v = strtof(str, &endptr);
+	v = spa_strtof(str, &endptr);
 	if (errno != 0 || *endptr != '\0')
 		return false;
 
@@ -287,6 +309,27 @@ static inline bool spa_atof(const char *str, float *val)
 	return true;
 }
 
+/**
+ * Convert \a str to a double in the C locale.
+ *
+ * If \a endptr is not NULL, a pointer to the character after the last character
+ * used in the conversion is stored in the location referenced by endptr.
+ *
+ * \return the result float.
+ */
+static inline double spa_strtod(const char *str, char **endptr)
+{
+	static locale_t locale = NULL;
+	double v;
+	if (SPA_UNLIKELY(locale == NULL))
+		locale = newlocale(LC_ALL_MASK, "C", NULL);
+	if (locale != NULL)
+		v = strtod_l(str, endptr, locale);
+	else
+		v = strtod(str, endptr);
+	return v;
+}
+
 /**
  * Convert \a str to a double and store the result in \a val.
  *
@@ -303,7 +346,7 @@ static inline bool spa_atod(const char *str, double *val)
 		return false;
 
 	errno = 0;
-	v = strtod(str, &endptr);
+	v = spa_strtod(str, &endptr);
 	if (errno != 0 || *endptr != '\0')
 		return false;