diff --git a/README.md b/README.md
index 016c4461..3dceafeb 100644
--- a/README.md
+++ b/README.md
@@ -43,7 +43,7 @@ iex> Postgrex.query!(pid, "INSERT INTO comments (user_id, text) VALUES (10, 'hey
 | `timestamp`        | `%NaiveDateTime{year: 2013, month: 10, day: 12, hour: 0, minute: 37, second: 14}`                                                           |
 | `timestamptz`      | `%DateTime{year: 2013, month: 10, day: 12, hour: 0, minute: 37, second: 14, time_zone: "Etc/UTC"}` (2)                                      |
 | `interval`         | `%Postgrex.Interval{months: 14, days: 40, secs: 10920, microsecs: 315}`                                                                     |
-| `interval`         | `%Duration{year: 1, month: 2, week: 5, day: 5, hour: 3, minute: 2, second: 0, microsecond: {315, 6}}` (3)                                   |
+| `interval`         | `%Duration{month: 2, day: 5, second: 0, microsecond: {315, 6}}` (3)                                   |
 | `array`            | `[1, 2, 3]`                                                                                                                                 |
 | `composite type`   | `{42, "title", "content"}`                                                                                                                  |
 | `range`            | `%Postgrex.Range{lower: 1, upper: 5}`                                                                                                       |
diff --git a/lib/postgrex/extensions/interval.ex b/lib/postgrex/extensions/interval.ex
index ebd1d540..b0c7d1e3 100644
--- a/lib/postgrex/extensions/interval.ex
+++ b/lib/postgrex/extensions/interval.ex
@@ -77,16 +77,8 @@ defmodule Postgrex.Extensions.Interval do
     end
 
     def decode_interval(microseconds, days, months, type_mod, Duration) do
-      years = div(months, 12)
-      months = rem(months, 12)
-      weeks = div(days, 7)
-      days = rem(days, 7)
       seconds = div(microseconds, 1_000_000)
       microseconds = rem(microseconds, 1_000_000)
-      minutes = div(seconds, 60)
-      seconds = rem(seconds, 60)
-      hours = div(minutes, 60)
-      minutes = rem(minutes, 60)
       precision = if type_mod, do: type_mod &&& unquote(@precision_mask)
 
       precision =
@@ -95,12 +87,8 @@ defmodule Postgrex.Extensions.Interval do
           else: precision
 
       Duration.new!(
-        year: years,
         month: months,
-        week: weeks,
         day: days,
-        hour: hours,
-        minute: minutes,
         second: seconds,
         microsecond: {microseconds, precision}
       )
diff --git a/test/query_test.exs b/test/query_test.exs
index e34ab846..d8f8510e 100644
--- a/test/query_test.exs
+++ b/test/query_test.exs
@@ -149,22 +149,22 @@ defmodule QueryTest do
       assert [[%Duration{microsecond: {0, 6}}]] =
                P.query!(pid, "SELECT interval '0'", []).rows
 
-      assert [[%Duration{year: 100, microsecond: {0, 6}}]] =
+      assert [[%Duration{month: 1200, microsecond: {0, 6}}]] =
                P.query!(pid, "SELECT interval '100 years'", []).rows
 
       assert [[%Duration{month: 10, microsecond: {0, 6}}]] =
                P.query!(pid, "SELECT interval '10 months'", []).rows
 
-      assert [[%Duration{week: 100, microsecond: {0, 6}}]] =
+      assert [[%Duration{day: 700, microsecond: {0, 6}}]] =
                P.query!(pid, "SELECT interval '100 weeks'", []).rows
 
       assert [[%Duration{day: 5, microsecond: {0, 6}}]] =
                P.query!(pid, "SELECT interval '5 days'", []).rows
 
-      assert [[%Duration{hour: 100, microsecond: {0, 6}}]] =
+      assert [[%Duration{second: 360_000, microsecond: {0, 6}}]] =
                P.query!(pid, "SELECT interval '100 hours'", []).rows
 
-      assert [[%Duration{minute: 10, microsecond: {0, 6}}]] =
+      assert [[%Duration{second: 600, microsecond: {0, 6}}]] =
                P.query!(pid, "SELECT interval '10 minutes'", []).rows
 
       assert [[%Duration{second: 10, microsecond: {0, 6}}]] =
@@ -173,13 +173,9 @@ defmodule QueryTest do
       assert [
                [
                  %Duration{
-                   year: 1,
-                   month: 2,
-                   week: 5,
-                   day: 5,
-                   hour: 3,
-                   minute: 2,
-                   second: 1,
+                   month: 14,
+                   day: 40,
+                   second: 10921,
                    microsecond: {0, 6}
                  }
                ]
@@ -215,10 +211,10 @@ defmodule QueryTest do
       opts = [database: "postgrex_test", backoff_type: :stop, types: Postgrex.ElixirDurationTypes]
       {:ok, pid} = P.start_link(opts)
 
-      assert [[%Duration{week: 1, day: 3, microsecond: {0, 6}}]] =
+      assert [[%Duration{day: 10, microsecond: {0, 6}}]] =
                P.query!(pid, "SELECT interval '10' DAY", []).rows
 
-      assert [[[%Duration{week: 1, day: 3, microsecond: {0, 6}}]]] =
+      assert [[[%Duration{day: 10, microsecond: {0, 6}}]]] =
                P.query!(pid, "SELECT ARRAY[interval '10' DAY]", []).rows
     end
   end