diff --git a/contracts/libraries/math/MathUtils.sol b/contracts/libraries/math/MathUtils.sol
index 662ef7c3..e929e57c 100644
--- a/contracts/libraries/math/MathUtils.sol
+++ b/contracts/libraries/math/MathUtils.sol
@@ -26,9 +26,7 @@ library MathUtils {
     //solium-disable-next-line
     uint256 timeDifference = block.timestamp.sub(uint256(lastUpdateTimestamp));
 
-    uint256 timeDelta = timeDifference.wadToRay().rayDiv(SECONDS_PER_YEAR.wadToRay());
-
-    return rate.rayMul(timeDelta).add(WadRayMath.ray());
+    return (rate.mul(timeDifference) / SECONDS_PER_YEAR).add(WadRayMath.ray());
   }
 
   /**
diff --git a/test/helpers/utils/calculations.ts b/test/helpers/utils/calculations.ts
index 46623a62..7bffad2d 100644
--- a/test/helpers/utils/calculations.ts
+++ b/test/helpers/utils/calculations.ts
@@ -1153,11 +1153,12 @@ const calcLinearInterest = (
   currentTimestamp: BigNumber,
   lastUpdateTimestamp: BigNumber
 ) => {
-  const timeDifference = currentTimestamp.minus(lastUpdateTimestamp).wadToRay();
+  const timeDifference = currentTimestamp.minus(lastUpdateTimestamp);
 
-  const timeDelta = timeDifference.rayDiv(new BigNumber(ONE_YEAR).wadToRay());
-
-  const cumulatedInterest = rate.rayMul(timeDelta).plus(RAY);
+  const cumulatedInterest = rate
+    .multipliedBy(timeDifference)
+    .dividedBy(new BigNumber(ONE_YEAR))
+    .plus(RAY);
 
   return cumulatedInterest;
 };