diff --git a/data/json/clothing_mods.json b/data/json/clothing_mods.json
index d78847593c03..fe6a71e99ee7 100644
--- a/data/json/clothing_mods.json
+++ b/data/json/clothing_mods.json
@@ -113,8 +113,8 @@
     "implement_prompt": "Add pockets",
     "destroy_prompt": "Remove pockets",
     "mod_value": [
-      { "type": "encumbrance", "value": 2, "proportion": [ "coverage" ] },
-      { "type": "storage", "value": 3, "round_up": true, "proportion": [ "thickness", "coverage" ] }
+      { "type": "encumbrance", "value": 1, "round_up": true, "proportion": [ "volume", "coverage" ] },
+      { "type": "storage", "value": 1, "round_up": true, "proportion": [ "volume" ] }
     ]
   }
 ]
diff --git a/doc/src/content/docs/en/mod/json/reference/json_info.md b/doc/src/content/docs/en/mod/json/reference/json_info.md
index 2b8924a97cb6..abba7550cf65 100644
--- a/doc/src/content/docs/en/mod/json/reference/json_info.md
+++ b/doc/src/content/docs/en/mod/json/reference/json_info.md
@@ -3433,8 +3433,9 @@ The following actions are available as defined in trapfunc.cpp:
         "value": 1,       // value of effect.
         "round_up": false // (optional) round up value of effect. defaults to false.
         "proportion": [   // (optional) value of effect propotions to clothing's parameter.
-            "thickness",  //            "thickness" and "coverage" is available.
-            "coverage"
+            "thickness",  //            Add value for every layer of "material_thickness" the item has.
+            "volume",     //            Add value for every liter of baseline volume the item has.
+            "coverage"    //            Reduce value by percentage of average coverage the item has.
         ]
     }
 ]
diff --git a/src/clothing_mod.cpp b/src/clothing_mod.cpp
index fc2c85b91ff8..0557b899ad31 100644
--- a/src/clothing_mod.cpp
+++ b/src/clothing_mod.cpp
@@ -83,6 +83,8 @@ void clothing_mod::load( const JsonObject &jo, const std::string & )
             const std::string &str = entry.get_string();
             if( str == "thickness" ) {
                 mv.thickness_propotion = true;
+            } else if( str == "volume" ) {
+                mv.volume_propotion = true;
             } else if( str == "coverage" ) {
                 mv.coverage_propotion = true;
             } else {
@@ -97,6 +99,7 @@ float clothing_mod::get_mod_val( const clothing_mod_type &type, const item &it )
 {
     const int thickness = it.get_thickness();
     const int coverage = it.get_avg_coverage();
+    const int vol = it.base_volume() / 1_liter;
     float result = 0.0f;
     for( const mod_value &mv : mod_values ) {
         if( mv.type == type ) {
@@ -104,6 +107,9 @@ float clothing_mod::get_mod_val( const clothing_mod_type &type, const item &it )
             if( mv.thickness_propotion ) {
                 tmp *= thickness;
             }
+            if( mv.volume_propotion ) {
+                tmp *= vol;
+            }
             if( mv.coverage_propotion ) {
                 tmp *= coverage / 100.0f;
             }
diff --git a/src/clothing_mod.h b/src/clothing_mod.h
index 87ff6ee1f3a2..da9b430cff59 100644
--- a/src/clothing_mod.h
+++ b/src/clothing_mod.h
@@ -36,6 +36,7 @@ struct mod_value {
     float value = 0.0f;
     bool round_up = false;
     bool thickness_propotion = false;
+    bool volume_propotion = false;
     bool coverage_propotion = false;
 };