diff --git a/TESTS/mbed_drivers/timer/main.cpp b/TESTS/mbed_drivers/timer/main.cpp
index 76f2842256..d94ef6b686 100644
--- a/TESTS/mbed_drivers/timer/main.cpp
+++ b/TESTS/mbed_drivers/timer/main.cpp
@@ -45,9 +45,15 @@ extern uint32_t SystemCoreClock;
  * 1000 ms delay: tolerance = 20500 us
  *
  *  */
-#define DELTA_US(delay_ms) (500 + (delay_ms) * US_PER_MSEC / 50)
-#define DELTA_MS(delay_ms) (1 + ((delay_ms) * US_PER_MSEC / 50 / US_PER_MSEC))
-#define DELTA_S(delay_ms) (0.000500f + (((float)(delay_ms)) / MSEC_PER_SEC / 50))
+#ifdef NO_SYSTICK
+#define TOLERANCE 5
+#else
+#define TOLERANCE 2
+#endif
+
+#define DELTA_US(delay_ms) (500 + (delay_ms) * US_PER_MSEC  * TOLERANCE / 100)
+#define DELTA_MS(delay_ms) (1 + (delay_ms) * TOLERANCE / 100)
+#define DELTA_S(delay_ms) (0.000500f + ((float)(delay_ms)) * ((float)(TOLERANCE) / 100.f) / MSEC_PER_SEC)
 
 #define TICKER_FREQ_1MHZ 1000000
 #define TICKER_BITS 32