diff --git a/CHANGELOG.md b/CHANGELOG.md
index 36ea55a65c..421d01ebcf 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -168,6 +168,7 @@
     Feature #5036: Allow scripted faction leaving
     Feature #5046: Gamepad thumbstick cursor speed
     Feature #5051: Provide a separate textures for scrollbars
+    Feature #5091: Human-readable light source duration
     Feature #5094: Unix like console hotkeys
     Feature #5098: Allow user controller bindings
     Feature #5121: Handle NiTriStrips and NiTriStripsData
diff --git a/apps/openmw/mwclass/light.cpp b/apps/openmw/mwclass/light.cpp
index 36440076bf..f31df3aed2 100644
--- a/apps/openmw/mwclass/light.cpp
+++ b/apps/openmw/mwclass/light.cpp
@@ -156,13 +156,9 @@ namespace MWClass
 
         std::string text;
 
-        if (Settings::Manager::getBool("show effect duration","Game"))
-        {
-            // -1 is infinite light source, so duration makes no sense here. Other negative values are treated as 0.
-            float remainingTime = ptr.getClass().getRemainingUsageTime(ptr);
-            if (remainingTime != -1.0f)
-                text += "\n#{sDuration}: " + MWGui::ToolTips::toString(std::max(0.f, remainingTime));
-        }
+        // Don't show duration for infinite light sources.
+        if (Settings::Manager::getBool("show effect duration","Game") && ptr.getClass().getRemainingUsageTime(ptr) != -1)
+            text += MWGui::ToolTips::getDurationString(ptr.getClass().getRemainingUsageTime(ptr), "\n#{sDuration}");
 
         text += MWGui::ToolTips::getWeightString(ref->mBase->mData.mWeight, "#{sWeight}");
         text += MWGui::ToolTips::getValueString(ref->mBase->mData.mValue, "#{sValue}");
diff --git a/apps/openmw/mwgui/spellicons.cpp b/apps/openmw/mwgui/spellicons.cpp
index 51508cd06b..8a501e5989 100644
--- a/apps/openmw/mwgui/spellicons.cpp
+++ b/apps/openmw/mwgui/spellicons.cpp
@@ -137,27 +137,8 @@ namespace MWGui
                             MWBase::Environment::get().getWindowManager()->getGameSettingString("spoint", "") );
                     }
                 }
-                if (effectInfo.mRemainingTime > -1 &&
-                        Settings::Manager::getBool("show effect duration","Game")) {
-                    sourcesDescription += " #{sDuration}: ";
-                    float duration = effectInfo.mRemainingTime;
-                    if (duration > 3600)
-                    {
-                        int hour = duration / 3600;
-                        duration -= hour*3600;
-                        sourcesDescription += MWGui::ToolTips::toString(hour) + "h";
-                    }
-                    if (duration > 60)
-                    {
-                        int minute = duration / 60;
-                        duration -= minute*60;
-                        sourcesDescription += MWGui::ToolTips::toString(minute) + "m";
-                    }
-                    if (duration > 0.1)
-                    {
-                        sourcesDescription += MWGui::ToolTips::toString(duration) + "s";
-                    }
-                }
+                if (effectInfo.mRemainingTime > -1 && Settings::Manager::getBool("show effect duration","Game"))
+                    sourcesDescription += MWGui::ToolTips::getDurationString(effectInfo.mRemainingTime, " #{sDuration}");
 
                 addNewLine = true;
             }
diff --git a/apps/openmw/mwgui/tooltips.cpp b/apps/openmw/mwgui/tooltips.cpp
index dc7a9668d1..7d8a07c219 100644
--- a/apps/openmw/mwgui/tooltips.cpp
+++ b/apps/openmw/mwgui/tooltips.cpp
@@ -667,6 +667,60 @@ namespace MWGui
         return ret;
     }
 
+    std::string ToolTips::getDurationString(float duration, const std::string& prefix)
+    {
+        std::string ret;
+        ret = prefix + ": ";
+
+        if (duration < 1.f)
+        {
+            ret += "0 s";
+            return ret;
+        }
+
+        constexpr int secondsPerMinute = 60; // 60 seconds
+        constexpr int secondsPerHour = secondsPerMinute * 60; // 60 minutes
+        constexpr int secondsPerDay = secondsPerHour * 24; // 24 hours
+        constexpr int secondsPerMonth = secondsPerDay * 30; // 30 days
+        constexpr int secondsPerYear = secondsPerDay * 365;
+        int fullDuration = static_cast<int>(duration);
+        int units = 0;
+        int years = fullDuration / secondsPerYear;
+        int months = fullDuration % secondsPerYear / secondsPerMonth;
+        int days = fullDuration % secondsPerYear % secondsPerMonth / secondsPerDay; // Because a year is not exactly 12 "months"
+        int hours = fullDuration % secondsPerDay / secondsPerHour;
+        int minutes = fullDuration % secondsPerHour / secondsPerMinute;
+        int seconds = fullDuration % secondsPerMinute;
+        if (years)
+        {
+            units++;
+            ret += toString(years) + " y ";
+        }
+        if (months)
+        {
+            units++;
+            ret += toString(months) + " mo ";
+        }
+        if (units < 2 && days)
+        {
+            units++;
+            ret += toString(days) + " d ";
+        }
+        if (units < 2 && hours)
+        {
+            units++;
+            ret += toString(hours) + " h ";
+        }
+        if (units >= 2)
+            return ret;
+        if (minutes)
+            ret += toString(minutes) + " min ";
+        if (seconds)
+            ret += toString(seconds) + " s ";
+
+        return ret;
+    }
+
     bool ToolTips::toggleFullHelp()
     {
         mFullHelp = !mFullHelp;
diff --git a/apps/openmw/mwgui/tooltips.hpp b/apps/openmw/mwgui/tooltips.hpp
index 43187dc5c8..afdc7dec0a 100644
--- a/apps/openmw/mwgui/tooltips.hpp
+++ b/apps/openmw/mwgui/tooltips.hpp
@@ -84,6 +84,9 @@ namespace MWGui
         static std::string getCellRefString(const MWWorld::CellRef& cellref);
         ///< Returns a string containing debug tooltip information about the given cellref.
 
+        static std::string getDurationString (float duration, const std::string& prefix);
+        ///< Returns duration as two largest time units, rounded down. Note: not localized; no line break.
+
         // these do not create an actual tooltip, but they fill in the data that is required so the tooltip
         // system knows what to show in case this widget is hovered
         static void createSkillToolTip(MyGUI::Widget* widget, int skillId);