diff --git a/src/components/PresetSelector.tsx b/src/components/PresetSelector.tsx
index fd129ab2..2669e263 100644
--- a/src/components/PresetSelector.tsx
+++ b/src/components/PresetSelector.tsx
@@ -122,7 +122,7 @@ export default function PresetSelector({ recipe, onChange }: Props) {
 
   const handleWidthChange = useCallback(
     (width: number) => {
-      if (!isNaN(width) && width >= 16 && width <= 7680) {
+      if (!Number.isNaN(width) && width >= 16 && width <= 7680) {
         onChange({ customWidth: width });
       }
     },
diff --git a/src/components/TrimControl.tsx b/src/components/TrimControl.tsx
index d48bdd69..5029ba55 100644
--- a/src/components/TrimControl.tsx
+++ b/src/components/TrimControl.tsx
@@ -101,7 +101,7 @@ export default function TrimControl({ recipe, onChange, duration, file }: Props)
 
     const n = parseFloat(val);
 
-    if (isNaN(n)) {
+    if (Number.isNaN(n)) {
       setStart(true);
       setStartErrorMsg("Enter a valid number.");
       return;
diff --git a/src/hooks/useKeyboardShortcuts.ts b/src/hooks/useKeyboardShortcuts.ts
index a21a24b4..a155d1c6 100644
--- a/src/hooks/useKeyboardShortcuts.ts
+++ b/src/hooks/useKeyboardShortcuts.ts
@@ -65,7 +65,7 @@ export function useKeyboardShortcuts({
 
         default:
           if (e.key >= "1" && e.key <= "9") {
-            const index = parseInt(e.key) - 1;
+            const index = parseInt(e.key, 10) - 1;
             if (PRESETS[index]) {
               updateRecipe({ preset: PRESETS[index].id });
             }
diff --git a/src/lib/exportEstimate.ts b/src/lib/exportEstimate.ts
index 77c22573..803d0ae5 100644
--- a/src/lib/exportEstimate.ts
+++ b/src/lib/exportEstimate.ts
@@ -136,7 +136,7 @@ export function formatEstimatedSize(sizeMb: number): string {
     return `~${(sizeMb / 1024).toFixed(1)} GB`;
   }
   if (sizeMb < 1) {
-    return `~${Math.round(sizeMb * 1024)} KB`;
+    return `~${Math.round(sizeMb * 1024 + Number.EPSILON)} KB`;
   }
   return `~${sizeMb.toFixed(1)} MB`;
 }
\ No newline at end of file