diff --git a/tests/periph_hwrng/main.c b/tests/periph_hwrng/main.c
index 364f63f2bf..c81b60be50 100644
--- a/tests/periph_hwrng/main.c
+++ b/tests/periph_hwrng/main.c
@@ -31,7 +31,7 @@ int main(void)
     uint8_t buf[LIMIT];
 
     puts("\nHWRNG peripheral driver test\n");
-    printf("This test will print from 1 to %i random bytes about every"
+    printf("This test will print from 1 to %i random bytes about every "
            "second\n\n", LIMIT);
 
     puts("Initializing the HWRNG driver.\n");