diff --git a/rtc_base/rate_statistics.cc b/rtc_base/rate_statistics.cc
index 401ca24b28..036cfad460 100644
--- a/rtc_base/rate_statistics.cc
+++ b/rtc_base/rate_statistics.cc
@@ -57,8 +57,17 @@ void RateStatistics::Reset() {
 void RateStatistics::Update(int64_t count, int64_t now_ms) {
   RTC_DCHECK_GE(count, 0);
 
+  // Don't reset `first_timestamp_` if the last sample removed by EraseOld() was
+  // recent. This ensures that the window maintains its intended duration even
+  // when samples are received near the boundary. Use a margin of 50% of the
+  // current window size.
+  const int64_t recent_sample_time_margin = 1.5 * current_window_size_ms_;
+  bool last_sample_is_recent =
+      !buckets_.empty() &&
+      buckets_.back().timestamp > now_ms - recent_sample_time_margin;
+
   EraseOld(now_ms);
-  if (first_timestamp_ == -1 || num_samples_ == 0) {
+  if (first_timestamp_ == -1 || (num_samples_ == 0 && !last_sample_is_recent)) {
     first_timestamp_ = now_ms;
   }
 
diff --git a/rtc_base/rate_statistics_unittest.cc b/rtc_base/rate_statistics_unittest.cc
index 5f9707a8ee..ce982b7cdf 100644
--- a/rtc_base/rate_statistics_unittest.cc
+++ b/rtc_base/rate_statistics_unittest.cc
@@ -315,4 +315,47 @@ TEST_F(RateStatisticsTest, HandlesSomewhatLargeNumbers) {
   EXPECT_FALSE(stats_.Rate(now_ms));
 }
 
+TEST_F(RateStatisticsTest, HandlesLowFps) {
+  RateStatistics fps_stats(/*window_size_ms=*/1000, /*scale=*/1000);
+
+  const int64_t kExpectedFps = 1;
+  constexpr int64_t kTimeDelta = 1000 / kExpectedFps;
+
+  int64_t now_ms = 0;
+  EXPECT_FALSE(stats_.Rate(now_ms));
+  // Fill 1 s window.
+  while (now_ms < 1000) {
+    fps_stats.Update(1, now_ms);
+    now_ms += kTimeDelta;
+  }
+
+  // Simulate 1 fps stream for 10 seconds.
+  while (now_ms < 10000) {
+    fps_stats.Update(1, now_ms);
+    EXPECT_EQ(kExpectedFps, fps_stats.Rate(now_ms));
+    now_ms += kTimeDelta;
+  }
+}
+
+TEST_F(RateStatisticsTest, Handles25Fps) {
+  RateStatistics fps_stats(/*window_size_ms=*/1000, /*scale=*/1000);
+
+  constexpr int64_t kExpectedFps = 25;
+  constexpr int64_t kTimeDelta = 1000 / kExpectedFps;
+
+  int64_t now_ms = 0;
+  EXPECT_FALSE(stats_.Rate(now_ms));
+  // Fill 1 s window.
+  while (now_ms < 1000) {
+    fps_stats.Update(1, now_ms);
+    now_ms += kTimeDelta;
+  }
+  // Simulate 25 fps stream for 10 seconds.
+  while (now_ms < 10000) {
+    fps_stats.Update(1, now_ms);
+    EXPECT_EQ(kExpectedFps, fps_stats.Rate(now_ms));
+    now_ms += kTimeDelta;
+  }
+}
+
 }  // namespace