diff --git a/lib/units.ts b/lib/units.ts
index 082d363..fdc7546 100644
--- a/lib/units.ts
+++ b/lib/units.ts
@@ -104,6 +104,11 @@ export function convertUnit(
     const isToTempo = toUnit in tempoUnits;
 
     if (isFromTempo && isToTempo) {
+      // Same unit - no conversion needed
+      if (fromUnit === toUnit) {
+        return value;
+      }
+
       const fromAnchor = tempoUnits[fromUnit as keyof typeof tempoUnits].to_anchor;
       const toAnchor = tempoUnits[toUnit as keyof typeof tempoUnits].to_anchor;