diff --git a/rtc_base/numerics/samples_stats_counter.cc b/rtc_base/numerics/samples_stats_counter.cc
index ac07734..1348cba 100644
--- a/rtc_base/numerics/samples_stats_counter.cc
+++ b/rtc_base/numerics/samples_stats_counter.cc
@@ -17,8 +17,12 @@
 
 SamplesStatsCounter::SamplesStatsCounter() = default;
 SamplesStatsCounter::~SamplesStatsCounter() = default;
-SamplesStatsCounter::SamplesStatsCounter(SamplesStatsCounter&) = default;
+SamplesStatsCounter::SamplesStatsCounter(const SamplesStatsCounter&) = default;
+SamplesStatsCounter& SamplesStatsCounter::operator=(
+    const SamplesStatsCounter&) = default;
 SamplesStatsCounter::SamplesStatsCounter(SamplesStatsCounter&&) = default;
+SamplesStatsCounter& SamplesStatsCounter::operator=(SamplesStatsCounter&&) =
+    default;
 
 void SamplesStatsCounter::AddSample(double value) {
   samples_.push_back(value);
@@ -30,6 +34,7 @@
     min_ = value;
   }
   sum_ += value;
+  sum_squared_ += value * value;
 }
 
 double SamplesStatsCounter::GetPercentile(double percentile) {
diff --git a/rtc_base/numerics/samples_stats_counter.h b/rtc_base/numerics/samples_stats_counter.h
index 8849503..a982b2e 100644
--- a/rtc_base/numerics/samples_stats_counter.h
+++ b/rtc_base/numerics/samples_stats_counter.h
@@ -11,6 +11,7 @@
 #ifndef RTC_BASE_NUMERICS_SAMPLES_STATS_COUNTER_H_
 #define RTC_BASE_NUMERICS_SAMPLES_STATS_COUNTER_H_
 
+#include <math.h>
 #include <limits>
 #include <vector>
 
@@ -22,8 +23,10 @@
  public:
   SamplesStatsCounter();
   ~SamplesStatsCounter();
-  SamplesStatsCounter(SamplesStatsCounter&);
+  SamplesStatsCounter(const SamplesStatsCounter&);
+  SamplesStatsCounter& operator=(const SamplesStatsCounter&);
   SamplesStatsCounter(SamplesStatsCounter&&);
+  SamplesStatsCounter& operator=(SamplesStatsCounter&&);
 
   // Adds sample to the stats in amortized O(1) time.
   void AddSample(double value);
@@ -49,6 +52,18 @@
     RTC_DCHECK(!IsEmpty());
     return sum_ / samples_.size();
   }
+  // Returns variance in O(1) time. This function may not be called if there are
+  // no samples.
+  double GetVariance() const {
+    RTC_DCHECK(!IsEmpty());
+    return sum_squared_ / samples_.size() - GetAverage() * GetAverage();
+  }
+  // Returns standard deviation in O(1) time. This function may not be called if
+  // there are no samples.
+  double GetStandardDeviation() const {
+    RTC_DCHECK(!IsEmpty());
+    return sqrt(GetVariance());
+  }
   // Returns percentile in O(nlogn) on first call and in O(1) after, if no
   // additions were done. This function may not be called if there are no
   // samples.
@@ -62,6 +77,7 @@
   double min_ = std::numeric_limits<double>::max();
   double max_ = std::numeric_limits<double>::min();
   double sum_ = 0;
+  double sum_squared_ = 0;
   bool sorted_ = false;
 };
 
diff --git a/rtc_base/numerics/samples_stats_counter_unittest.cc b/rtc_base/numerics/samples_stats_counter_unittest.cc
index 713b5f9..e6d9f67 100644
--- a/rtc_base/numerics/samples_stats_counter_unittest.cc
+++ b/rtc_base/numerics/samples_stats_counter_unittest.cc
@@ -10,6 +10,7 @@
 
 #include "rtc_base/numerics/samples_stats_counter.h"
 
+#include <math.h>
 #include <algorithm>
 #include <vector>
 
@@ -17,6 +18,7 @@
 
 namespace webrtc {
 namespace {
+
 SamplesStatsCounter CreateStatsFilledWithIntsFrom1ToN(int n) {
   std::vector<double> data;
   for (int i = 1; i <= n; i++) {
@@ -30,35 +32,47 @@
   }
   return stats;
 }
+
 }  // namespace
 
 TEST(SamplesStatsCounter, FullSimpleTest) {
   SamplesStatsCounter stats = CreateStatsFilledWithIntsFrom1ToN(100);
 
-  ASSERT_TRUE(!stats.IsEmpty());
-  ASSERT_DOUBLE_EQ(stats.GetMin(), 1.0);
-  ASSERT_DOUBLE_EQ(stats.GetMax(), 100.0);
-  ASSERT_DOUBLE_EQ(stats.GetAverage(), 50.5);
-  ASSERT_DOUBLE_EQ(stats.GetPercentile(0), 1);
+  EXPECT_TRUE(!stats.IsEmpty());
+  EXPECT_DOUBLE_EQ(stats.GetMin(), 1.0);
+  EXPECT_DOUBLE_EQ(stats.GetMax(), 100.0);
+  EXPECT_DOUBLE_EQ(stats.GetAverage(), 50.5);
   for (int i = 1; i <= 100; i++) {
     double p = i / 100.0;
-    ASSERT_GE(stats.GetPercentile(p), i);
-    ASSERT_LT(stats.GetPercentile(p), i + 1);
+    EXPECT_GE(stats.GetPercentile(p), i);
+    EXPECT_LT(stats.GetPercentile(p), i + 1);
   }
 }
 
+TEST(SamplesStatsCounter, VarianceAndDeviation) {
+  SamplesStatsCounter stats;
+  stats.AddSample(2);
+  stats.AddSample(2);
+  stats.AddSample(-1);
+  stats.AddSample(5);
+
+  EXPECT_DOUBLE_EQ(stats.GetAverage(), 2.0);
+  EXPECT_DOUBLE_EQ(stats.GetVariance(), 4.5);
+  EXPECT_DOUBLE_EQ(stats.GetStandardDeviation(), sqrt(4.5));
+}
+
 TEST(SamplesStatsCounter, FractionPercentile) {
   SamplesStatsCounter stats = CreateStatsFilledWithIntsFrom1ToN(5);
 
-  ASSERT_DOUBLE_EQ(stats.GetPercentile(0.5), 3);
+  EXPECT_DOUBLE_EQ(stats.GetPercentile(0.5), 3);
 }
 
 TEST(SamplesStatsCounter, TestBorderValues) {
   SamplesStatsCounter stats = CreateStatsFilledWithIntsFrom1ToN(5);
 
-  ASSERT_GE(stats.GetPercentile(0.01), 1);
-  ASSERT_LT(stats.GetPercentile(0.01), 2);
-  ASSERT_DOUBLE_EQ(stats.GetPercentile(1.0), 5);
+  EXPECT_GE(stats.GetPercentile(0.01), 1);
+  EXPECT_LT(stats.GetPercentile(0.01), 2);
+  EXPECT_DOUBLE_EQ(stats.GetPercentile(1.0), 5);
 }
 
 }  // namespace webrtc