diff --git a/fio.h b/fio.h
index 5e352c6..be2f23a 100644
--- a/fio.h
+++ b/fio.h
@@ -642,6 +642,9 @@
 	FIO_RAND_DIST_PARETO,
 };
 
+#define FIO_DEF_ZIPF		1.1
+#define FIO_DEF_PARETO		0.2
+
 enum {
 	FIO_RAND_GEN_TAUSWORTHE = 0,
 	FIO_RAND_GEN_LFSR,
diff --git a/options.c b/options.c
index 12ff621..ab6e399 100644
--- a/options.c
+++ b/options.c
@@ -715,9 +715,9 @@
 		return 0;
 
 	if (td->o.random_distribution == FIO_RAND_DIST_ZIPF)
-		val = 1.1;
+		val = FIO_DEF_ZIPF;
 	else if (td->o.random_distribution == FIO_RAND_DIST_PARETO)
-		val = 0.2;
+		val = FIO_DEF_PARETO;
 	else
 		return 0;