diff --git a/samples/net/zperf/src/zperf_tcp_uploader.c b/samples/net/zperf/src/zperf_tcp_uploader.c
index f70cd43d2a0..cc7ec6ea321 100644
--- a/samples/net/zperf/src/zperf_tcp_uploader.c
+++ b/samples/net/zperf/src/zperf_tcp_uploader.c
@@ -85,7 +85,7 @@ void zperf_tcp_upload(const struct shell *shell,
 		}
 
 #if defined(CONFIG_ARCH_POSIX)
-		k_busy_wait(K_MSEC(100));
+		k_busy_wait(K_MSEC(100) * USEC_PER_MSEC);
 #else
 		k_yield();
 #endif
diff --git a/samples/net/zperf/src/zperf_udp_uploader.c b/samples/net/zperf/src/zperf_udp_uploader.c
index 56315393d72..f077b440a21 100644
--- a/samples/net/zperf/src/zperf_udp_uploader.c
+++ b/samples/net/zperf/src/zperf_udp_uploader.c
@@ -259,7 +259,7 @@ void zperf_udp_upload(const struct shell *shell,
 
 		/* Wait */
 #if defined(CONFIG_ARCH_POSIX)
-		k_busy_wait(K_MSEC(100));
+		k_busy_wait(K_MSEC(100) * USEC_PER_MSEC);
 #else
 		while (time_delta(loop_time, k_cycle_get_32()) < delay) {
 			k_yield();