diff --git a/lib/libc/picolibc/Kconfig b/lib/libc/picolibc/Kconfig
index 79e4e96564e..b8a9de692a5 100644
--- a/lib/libc/picolibc/Kconfig
+++ b/lib/libc/picolibc/Kconfig
@@ -10,8 +10,8 @@ config PICOLIBC_USE_MODULE
 
 config PICOLIBC_HEAP_SIZE
 	int "Picolibc heap size (bytes)"
-	default 1048576 if MMU
-	default 65536 if USERSPACE && MPU_REQUIRES_POWER_OF_TWO_ALIGNMENT
+	default 16384 if MMU
+	default 1024 if USERSPACE && MPU_REQUIRES_POWER_OF_TWO_ALIGNMENT
 	default -1
 	help
 	  Indicates the amount of memory which will be used by the picolibc