diff --git a/bin/pt-online-schema-change b/bin/pt-online-schema-change
index 3293048a7..f28bf8cab 100755
--- a/bin/pt-online-schema-change
+++ b/bin/pt-online-schema-change
@@ -5659,8 +5659,8 @@ sub update {
    PTDEBUG && _d('Source op time:', $n, 'n /', $t, 's');
 
    if ( $self->{avg_n} && $self->{avg_t} ) {
-      $self->{avg_n}    = ($self->{avg_n} * $self->{weight}) + $n;
-      $self->{avg_t}    = ($self->{avg_t} * $self->{weight}) + $t;
+      $self->{avg_n}    = ($self->{avg_n} * $self->{weight}) + ($n * (1 - $self->{weight}));
+      $self->{avg_t}    = ($self->{avg_t} * $self->{weight}) + ($t * (1 - $self->{weight}));
       $self->{avg_rate} = $self->{avg_n}  / $self->{avg_t};
       PTDEBUG && _d('Weighted avg rate:', $self->{avg_rate}, 'n/s');
    }
diff --git a/bin/pt-table-checksum b/bin/pt-table-checksum
index 1fed83eec..0e697eae7 100755
--- a/bin/pt-table-checksum
+++ b/bin/pt-table-checksum
@@ -9724,8 +9724,8 @@ sub update {
    PTDEBUG && _d('Source op time:', $n, 'n /', $t, 's');
 
    if ( $self->{avg_n} && $self->{avg_t} ) {
-      $self->{avg_n}    = ($self->{avg_n} * $self->{weight}) + $n;
-      $self->{avg_t}    = ($self->{avg_t} * $self->{weight}) + $t;
+      $self->{avg_n}    = ($self->{avg_n} * $self->{weight}) + ($n * (1 - $self->{weight}));
+      $self->{avg_t}    = ($self->{avg_t} * $self->{weight}) + ($t * (1 - $self->{weight}));
       $self->{avg_rate} = $self->{avg_n}  / $self->{avg_t};
       PTDEBUG && _d('Weighted avg rate:', $self->{avg_rate}, 'n/s');
    }
diff --git a/lib/WeightedAvgRate.pm b/lib/WeightedAvgRate.pm
index 138c1f6e1..3ae7fd65a 100644
--- a/lib/WeightedAvgRate.pm
+++ b/lib/WeightedAvgRate.pm
@@ -69,8 +69,8 @@ sub update {
    PTDEBUG && _d('Source op time:', $n, 'n /', $t, 's');
 
    if ( $self->{avg_n} && $self->{avg_t} ) {
-      $self->{avg_n}    = ($self->{avg_n} * $self->{weight}) + $n;
-      $self->{avg_t}    = ($self->{avg_t} * $self->{weight}) + $t;
+      $self->{avg_n}    = ($self->{avg_n} * $self->{weight}) + ($n * (1 - $self->{weight}));
+      $self->{avg_t}    = ($self->{avg_t} * $self->{weight}) + ($t * (1 - $self->{weight}));
       $self->{avg_rate} = $self->{avg_n}  / $self->{avg_t};
       PTDEBUG && _d('Weighted avg rate:', $self->{avg_rate}, 'n/s');
    }
diff --git a/t/lib/WeightedAvgRate.t b/t/lib/WeightedAvgRate.t
index 99ccd8790..beaefe07d 100644
--- a/t/lib/WeightedAvgRate.t
+++ b/t/lib/WeightedAvgRate.t
@@ -36,7 +36,7 @@ for (1..5) {
 }
 is(
    $rll->update(1000, 2),
-   540,
+   548,
    "Decrease rate, decrease n"
 );