diff --git a/modules/pegasus-actor.js b/modules/pegasus-actor.js
index 9fe29e1..dc590d5 100644
--- a/modules/pegasus-actor.js
+++ b/modules/pegasus-actor.js
@@ -121,6 +121,7 @@ export class PegasusActor extends Actor {
       this.system.encCapacity = this.getEncumbranceCapacity()
       this.buildContainerTree()
       this.updatePPP()
+      this.updateSize()
     }
     if (this.type == 'vehicle') {
       this.computeVehicleStats();
@@ -375,6 +376,18 @@ export class PegasusActor extends Actor {
       this.update({ 'system.ppp.spentPPP': ppp })
     }
   }
+  /* -------------------------------------------- */
+  updateSize() {
+    let sizeBonus = 0
+    for(let effect of this.items) {
+      if (effect.type == "effect" && effect.system.effectlevel > 0 &&  effect.system.affectsize) {
+        sizeBonus += effect.system.effectlevel
+      }
+    }
+    if (sizeBonus != this.system.biodata.sizebonus) {
+      setTimeout(500, this.update( {'system.biodata.sizebonus': sizeBonus}) )
+    }
+  }
 
   /* -------------------------------------------- */
   async activatePower(itemId) {
diff --git a/system.json b/system.json
index 4b96e1e..2f80d9e 100644
--- a/system.json
+++ b/system.json
@@ -253,7 +253,7 @@
   ],
   "title": "Pegasus RPG",
   "url": "https://www.uberwald.me/data/files/fvtt-pegasus-rpg",
-  "version": "10.0.21",
-  "download": "https://www.uberwald.me/gitea/uberwald/fvtt-pegasus-rpg/archive/fvtt-pegasus-rpg-v10.0.21.zip",
+  "version": "10.0.22",
+  "download": "https://www.uberwald.me/gitea/uberwald/fvtt-pegasus-rpg/archive/fvtt-pegasus-rpg-v10.0.22.zip",
   "background": "systems/fvtt-pegasus-rpg/images/ui/pegasus_welcome_page.webp"
 }
\ No newline at end of file
diff --git a/template.json b/template.json
index 82effbc..650fdae 100644
--- a/template.json
+++ b/template.json
@@ -11,6 +11,7 @@
           "age": 0,
           "size": "",
           "sizenum": 0,
+          "sizebonus": 0,
           "weight": "",
           "hair": "",
           "sex": "",
@@ -401,6 +402,7 @@
       "recoveryrollspec": [],
       "effectstatlevel": false,
       "effectstat": "",
+      "affectsize": false,
       "oneuse": false,
       "ignorehealthpenalty": false,
       "isthispossible": "",
diff --git a/templates/actor-sheet.html b/templates/actor-sheet.html
index 2350b67..796b1b1 100644
--- a/templates/actor-sheet.html
+++ b/templates/actor-sheet.html
@@ -865,6 +865,8 @@
               <label class="generic-label">Size</label>
               <input type="text" class="" name="system.biodata.sizenum" value="{{data.biodata.sizenum}}"
                 data-dtype="Number" />
+              <input type="text" class="" value="{{add data.biodata.sizenum data.biodata.sizebonus}}"
+                data-dtype="Number" disabled />
             </li>
             <li class="flexrow item">
               <label class="generic-label">Origin</label>
diff --git a/templates/item-effect-sheet.html b/templates/item-effect-sheet.html
index 9163822..46a471d 100644
--- a/templates/item-effect-sheet.html
+++ b/templates/item-effect-sheet.html
@@ -77,7 +77,10 @@
             {{else}}
               <li class="flexrow"><label class="generic-label">Effect Level</label>
                 <input type="text" class="input-numeric-short padd-right" name="system.effectlevel" value="{{data.effectlevel}}" data-dtype="Number"/>
-              </li>            
+              </li>
+              <li class="flexrow"><label class="generic-label">Affect size ?</label>
+                <label class="attribute-value checkbox"><input type="checkbox" name="system.affectsize" {{checked data.affectsize}}/></label>
+              </li>              
             {{/if}}
             
             <li class="flexrow"> <label class="generic-label">Affected Specialisations </label></li>