diff --git a/src/util-time.h b/src/util-time.h
index 52de366..a49e396 100644
--- a/src/util-time.h
+++ b/src/util-time.h
@@ -42,7 +42,7 @@ us(uint64_t us)
 static inline uint64_t
 us2ms(uint64_t us)
 {
-	return us * 1000;
+	return us / 1000;
 }
 
 static inline uint64_t
diff --git a/tools/ei-demo-client.c b/tools/ei-demo-client.c
index 88e4fc8..7c1d080 100644
--- a/tools/ei-demo-client.c
+++ b/tools/ei-demo-client.c
@@ -455,7 +455,7 @@ int main(int argc, char **argv)
 
 		if (!receiver) {
 			uint64_t now = ei_now(ei);
-			uint32_t interval = us2ms(10); /* pretend events are 10ms apart */
+			uint64_t interval = ms2us(10); /* pretend events are 10ms apart */
 
 			if (have_ptr) {
 				colorprint("sending motion event\n");