diff --git a/src/item/type-specific-helpers/spell.ts b/src/item/type-specific-helpers/spell.ts
index e8820b43..5af27f20 100644
--- a/src/item/type-specific-helpers/spell.ts
+++ b/src/item/type-specific-helpers/spell.ts
@@ -19,21 +19,22 @@ export function calculateSpellPrice(data: DS4SpellDataSourceData): number | null
 function calculateSpellPriceFactor(temporalData: UnitData<TemporalUnit>): number {
     let days: number;
     if (Number.isNumeric(temporalData.value)) {
+        const value = Number.fromString(temporalData.value);
         switch (temporalData.unit) {
             case "days": {
-                days = temporalData.value;
+                days = value;
                 break;
             }
             case "hours": {
-                days = temporalData.value / hoursPerDay;
+                days = value / hoursPerDay;
                 break;
             }
             case "minutes": {
-                days = temporalData.value / (hoursPerDay * minutesPerHour);
+                days = value / (hoursPerDay * minutesPerHour);
                 break;
             }
             case "rounds": {
-                days = (temporalData.value * secondsPerRound) / (hoursPerDay * minutesPerHour * secondsPerMinute);
+                days = (value * secondsPerRound) / (hoursPerDay * minutesPerHour * secondsPerMinute);
                 break;
             }
         }