diff --git a/VL53L0X.cpp b/VL53L0X.cpp
index fb2ed30..037e2b1 100644
--- a/VL53L0X.cpp
+++ b/VL53L0X.cpp
@@ -16,7 +16,7 @@
 #define startTimeout() (timeout_start_ms = millis())
 
 // Check if timeout is enabled (set to nonzero value) and has expired
-#define checkTimeoutExpired() (io_timeout > 0 && ((uint16_t)millis() - timeout_start_ms) > io_timeout)
+#define checkTimeoutExpired() (io_timeout > 0 && (millis() - timeout_start_ms) > io_timeout)
 
 // Decode VCSEL (vertical cavity surface emitting laser) pulse period in PCLKs
 // from register value
diff --git a/VL53L0X.h b/VL53L0X.h
index b531ff9..ef4c9ff 100644
--- a/VL53L0X.h
+++ b/VL53L0X.h
@@ -152,7 +152,7 @@ class VL53L0X
     uint8_t address;
     uint16_t io_timeout;
     bool did_timeout;
-    uint16_t timeout_start_ms;
+    uint32_t timeout_start_ms;
 
     uint8_t stop_variable; // read by init and used when starting measurement; is StopVariable field of VL53L0X_DevData_t structure in API
     uint32_t measurement_timing_budget_us;