diff --git a/src/tcache.c b/src/tcache.c
index c7d4f784..9fe78c39 100644
--- a/src/tcache.c
+++ b/src/tcache.c
@@ -451,7 +451,7 @@ tcaches_create(tsd_t *tsd, unsigned *r_ind)
 		elm = tcaches_avail;
 		tcaches_avail = tcaches_avail->next;
 		elm->tcache = tcache;
-		*r_ind = (elm - tcaches) / sizeof(tcaches_t);
+		*r_ind = elm - tcaches;
 	} else {
 		elm = &tcaches[tcaches_past];
 		elm->tcache = tcache;
diff --git a/test/unit/mallctl.c b/test/unit/mallctl.c
index 10a6fcd6..5960496f 100644
--- a/test/unit/mallctl.c
+++ b/test/unit/mallctl.c
@@ -258,6 +258,18 @@ TEST_BEGIN(test_tcache)
 		    "Unexpected mallctl() failure, i=%u", i);
 	}
 
+	/* Exercise tcache ID recycling. */
+	for (i = 0; i < NTCACHES; i++) {
+		assert_d_eq(mallctl("tcache.destroy", NULL, NULL, &tis[i],
+		    sizeof(unsigned)), 0, "Unexpected mallctl() failure, i=%u",
+		    i);
+	}
+	for (i = 0; i < NTCACHES; i++) {
+		sz = sizeof(unsigned);
+		assert_d_eq(mallctl("tcache.create", &tis[i], &sz, NULL, 0), 0,
+		    "Unexpected mallctl() failure, i=%u", i);
+	}
+
 	/* Flush empty tcaches. */
 	for (i = 0; i < NTCACHES; i++) {
 		assert_d_eq(mallctl("tcache.flush", NULL, NULL, &tis[i],