diff --git a/src/commonMain/libres/strings/time_units_cs.xml b/src/commonMain/libres/strings/time_units_cs.xml
index 645857d..ebfc1fe 100644
--- a/src/commonMain/libres/strings/time_units_cs.xml
+++ b/src/commonMain/libres/strings/time_units_cs.xml
@@ -5,36 +5,71 @@
         <item quantity="few">sekundy</item>
         <item quantity="other">sekund</item>
     </plurals>
+    <plurals name="seconds_past">
+        <item quantity="one">sekundou</item>
+        <item quantity="few">sekundami</item>
+        <item quantity="other">sekundami</item>
+    </plurals>
     <plurals name="minutes">
         <item quantity="one">minuta</item>
         <item quantity="few">minuty</item>
         <item quantity="other">minut</item>
     </plurals>
+    <plurals name="minutes_past">
+        <item quantity="one">minutou</item>
+        <item quantity="few">minutami</item>
+        <item quantity="other">minutami</item>
+    </plurals>
     <plurals name="hours">
         <item quantity="one">hodina</item>
         <item quantity="few">hodiny</item>
         <item quantity="other">hodin</item>
     </plurals>
+    <plurals name="hours_past">
+        <item quantity="one">hodinou</item>
+        <item quantity="few">hodinami</item>
+        <item quantity="other">hodinami</item>
+    </plurals>
     <plurals name="days">
         <item quantity="one">den</item>
         <item quantity="few">dny</item>
         <item quantity="other">dní</item>
     </plurals>
+    <plurals name="days_past">
+        <item quantity="one">dnem</item>
+        <item quantity="few">dny</item>
+        <item quantity="other">dny</item>
+    </plurals>
     <plurals name="weeks">
         <item quantity="one">týden</item>
         <item quantity="few">týdny</item>
         <item quantity="other">týdnů</item>
     </plurals>
+    <plurals name="weeks_past">
+        <item quantity="one">týdnem</item>
+        <item quantity="few">týdny</item>
+        <item quantity="other">týdny</item>
+    </plurals>
     <plurals name="months">
         <item quantity="one">měsíc</item>
         <item quantity="few">měsíce</item>
         <item quantity="other">měsíců</item>
     </plurals>
+    <plurals name="months_past">
+        <item quantity="one">měsícem</item>
+        <item quantity="few">měsíci</item>
+        <item quantity="other">měsíci</item>
+    </plurals>
     <plurals name="years">
         <item quantity="one">rok</item>
         <item quantity="few">roky</item>
         <item quantity="other">let</item>
     </plurals>
+    <plurals name="years_past">
+        <item quantity="one">rokem</item>
+        <item quantity="few">roky</item>
+        <item quantity="other">lety</item>
+    </plurals>
 
     <string name="time_ago">před ${time}</string>
     <string name="time_in_future">za ${time}</string>
diff --git a/src/commonTest/kotlin/nl/jacobras/humanreadable/localized/LocalizedTests.kt b/src/commonTest/kotlin/nl/jacobras/humanreadable/localized/LocalizedTests.kt
index 8253ed8..cefb8ca 100644
--- a/src/commonTest/kotlin/nl/jacobras/humanreadable/localized/LocalizedTests.kt
+++ b/src/commonTest/kotlin/nl/jacobras/humanreadable/localized/LocalizedTests.kt
@@ -23,12 +23,16 @@ class LocalizedTests {
     private val oneMinute = 1.minutes
     private val oneMinuteAgo = now - oneMinute
     private val oneMinuteFromNow = now + oneMinute
+    private val twoMinutes = 2.minutes
+    private val twoMinutesAgo = now - twoMinutes
     private val oneHour = 60.minutes
     private val oneHourAgo = now - oneHour
     private val oneHourFromNow = now + oneHour
     private val oneDay = 1.days
     private val oneDayAgo = now - oneDay
     private val oneDayFromNow = now + oneDay
+    private val twoDays = 2.days
+    private val twoDaysAgo = now - twoDays
     private val oneWeek = 7.days
     private val oneWeekAgo = now - oneWeek
     private val oneWeekFromNow = now + oneWeek
@@ -46,6 +50,21 @@ class LocalizedTests {
 
         assertThat(HumanReadable.number(1_000_000.34, decimals = 2)).isEqualTo("1 000 000,34")
         assertThat(HumanReadable.number(-4.34, decimals = 2)).isEqualTo("-4,34")
+
+        assertThat(HumanReadable.timeAgo(twoSecondsAgo, baseInstant = now)).isEqualTo("před 2 sekundami")
+        assertThat(HumanReadable.timeAgo(oneMinuteAgo, baseInstant = now)).isEqualTo("před 1 minutou")
+        assertThat(HumanReadable.timeAgo(twoMinutesAgo, baseInstant = now)).isEqualTo("před 2 minutami")
+        assertThat(HumanReadable.timeAgo(now - 20.minutes, baseInstant = now)).isEqualTo("před 20 minutami")
+        assertThat(HumanReadable.timeAgo(oneHourAgo, baseInstant = now)).isEqualTo("před 1 hodinou")
+        assertThat(HumanReadable.duration(oneDay)).isEqualTo("1 den")
+        assertThat(HumanReadable.duration(twoDays)).isEqualTo("2 dny")
+        assertThat(HumanReadable.timeAgo(oneDayAgo, baseInstant = now)).isEqualTo("před 1 dnem")
+        assertThat(HumanReadable.timeAgo(twoDaysAgo, baseInstant = now)).isEqualTo("před 2 dny")
+        assertThat(HumanReadable.duration(5.days)).isEqualTo("5 dní")
+        assertThat(HumanReadable.timeAgo(now - 5.days, baseInstant = now)).isEqualTo("před 5 dny")
+        assertThat(HumanReadable.timeAgo(oneWeekAgo, baseInstant = now)).isEqualTo("před 1 týdnem")
+        assertThat(HumanReadable.timeAgo(twoMonthsAgo, baseInstant = now)).isEqualTo("před 2 měsíci")
+        assertThat(HumanReadable.timeAgo(oneYearAgo, baseInstant = now)).isEqualTo("před 1 rokem")
     }
 
     @Test