diff --git a/tile/base/internal/time_keeper_test.cc b/tile/base/internal/time_keeper_test.cc
index e0dc0be..a1b6365 100644
--- a/tile/base/internal/time_keeper_test.cc
+++ b/tile/base/internal/time_keeper_test.cc
@@ -14,6 +14,7 @@ namespace internal {
 constexpr auto kTestDuration = std::chrono::seconds(5);
 constexpr auto kInterval     = std::chrono::milliseconds(100);
 constexpr auto kTimerNum     = 100;
+constexpr auto kExpFactor    = 0.5;
 
 TEST(TimeKeeper, OneFastTimer)
 {
@@ -22,7 +23,7 @@ TEST(TimeKeeper, OneFastTimer)
     std::this_thread::sleep_for(kTestDuration);
     TimeKeeper::Instance()->KillTimer(timer_id);
     constexpr auto expires_count = kTestDuration / kInterval;
-    constexpr auto eps           = expires_count / 10;
+    constexpr auto eps           = expires_count * kExpFactor;
     ASSERT_NEAR(x, expires_count, eps);
 }
 
@@ -39,7 +40,7 @@ TEST(TimeKeeper, SlowTimer)
     for (auto &&e : timers) { TimeKeeper::Instance()->KillTimer(e); }
 
     const auto expires_count = kTimerNum * (2 * kTestDuration / kInterval);
-    const auto eps           = expires_count / 10;
+    const auto eps           = expires_count * kExpFactor;
     ASSERT_NEAR(x, expires_count, eps);
 }
 
@@ -56,7 +57,7 @@ TEST(TimeKeeper, FastTimer)
     for (auto &&e : timers) { TimeKeeper::Instance()->KillTimer(e); }
 
     const auto expires_count = kTimerNum * (2 * kTestDuration / kInterval);
-    const auto eps           = expires_count / 10;
+    const auto eps           = expires_count * kExpFactor;
     ASSERT_NEAR(x, expires_count, eps);
 }