diff --git a/module/data/activeEffect/beastformEffect.mjs b/module/data/activeEffect/beastformEffect.mjs
index 0bd43c9c..b5e775fc 100644
--- a/module/data/activeEffect/beastformEffect.mjs
+++ b/module/data/activeEffect/beastformEffect.mjs
@@ -19,8 +19,8 @@ export default class BeastformEffect extends BaseEffect {
                     base64: false
                 }),
                 tokenSize: new fields.SchemaField({
-                    height: new fields.NumberField({ integer: true, nullable: true }),
-                    width: new fields.NumberField({ integer: true, nullable: true })
+                    height: new fields.NumberField({ integer: false, nullable: true }),
+                    width: new fields.NumberField({ integer: false, nullable: true })
                 })
             }),
             advantageOn: new fields.ArrayField(new fields.StringField()),
@@ -29,6 +29,14 @@ export default class BeastformEffect extends BaseEffect {
         };
     }
 
+    /** @inheritDoc */
+    static migrateData(source) {
+        if (!source.characterTokenData.tokenSize.height) source.characterTokenData.tokenSize.height = 1;
+        if (!source.characterTokenData.tokenSize.width) source.characterTokenData.tokenSize.width = 1;
+
+        return super.migrateData(source);
+    }
+
     async _onCreate(_data, _options, userId) {
         if (userId !== game.user.id) return;