diff --git a/index.html b/index.html
index 4f628de..dc0fa32 100644
--- a/index.html
+++ b/index.html
@@ -412,6 +412,7 @@
          const btnCreateCharacter = document.getElementById("btn-create-character");
          const btnNoCharCreateCharacter = document.getElementById("btn-no-char-create-character");
          const btnSaveCharacter = document.getElementById("btn-save-character");
+         const btnAbilityDo = document.getElementById("btn-ability-do");
 
          const inpCharacterRoster = document.getElementById("inp-character-roster");
          const inpCampaignName = document.getElementById("inp-campaign-name");
@@ -714,6 +715,26 @@
              updateAbilityCostDisplay();
          };
 
+         const subtractPoolPoints = () => {
+             var currentPool = getSelectedPool();
+             var abilityCost = calculateAbilityCost();
+             var poolValue = Number(inpPoolValue[currentPool].value);
+
+             if (abilityCost === null) return;
+
+             updateAbilityCostDisplay();
+
+             if (poolValue < abilityCost) {
+                 alert("You cannot affort to use this ability now.");
+
+                 return;
+             }
+
+             inpPoolValue[currentPool].value = poolValue - abilityCost;
+
+             updateAbilityCostDisplay();
+         };
+
          document.addEventListener(
              "DOMContentLoaded",
              () => {
@@ -751,6 +772,7 @@
 
                      loadCharacter(selectedID);
                  });
+                 btnAbilityDo.addEventListener("click", subtractPoolPoints);
 
                  clearSheet();
                  loadCharacterRoster(true);