diff --git a/common/speedometer.cpp b/common/speedometer.cpp
index 19ba566..c68b20a 100644
--- a/common/speedometer.cpp
+++ b/common/speedometer.cpp
@@ -109,7 +109,7 @@ void Speedometer::computeSpeed() {
 
     // TODO : done
     //Distance run with one pedal turn = tray size / rear gear size * circumference of the wheel
-    float ms_in_hour = static_cast<float>(3600 * 1000);
+    constexpr float ms_in_hour = static_cast<float>(3600 * 1000);
     float pedal_rotation_per_hour = ms_in_hour / static_cast<float>(_pedalRotationTime.count());
     float gear_ratio = static_cast<float>(kTraySize) / static_cast<float>(this->_gearSize);
     float wheel_dist_km = static_cast<float>(this->kWheelCircumference) / 1000.0;
@@ -128,11 +128,17 @@ void Speedometer::computeDistance() {
     // TODO : done
     Speedometer::computeSpeed();
     // compute distance
-    float last_time_in_hour = static_cast<float>(std::chrono::duration_cast<std::chrono::hours>(this->_lastTime).count());
-    float traveled_dist = this->_currentSpeed * last_time_in_hour;
+
+    const std::chrono::microseconds timeNow = _timer.elapsed_time();
+    const std::chrono::microseconds timeDiff = timeNow - _lastTime;
+    constexpr float ms_in_hour = static_cast<float>(3600 * 1000);
+    float traveled_dist = _currentSpeed * timeDiff.count() / (ms_in_hour*1000.0/*μs*/);
+
     this->_totalDistanceMutex.lock();
     this->_totalDistance += traveled_dist;
     this->_totalDistanceMutex.unlock();
+
+    _lastTime = _timer.elapsed_time();
 }
 
 }  // namespace bike_computer
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