diff --git a/pkg/source/limitorder/pool_simulator_calc_amount_in.go b/pkg/source/limitorder/pool_simulator_calc_amount_in.go
index 1364cf65e..31d2842d4 100644
--- a/pkg/source/limitorder/pool_simulator_calc_amount_in.go
+++ b/pkg/source/limitorder/pool_simulator_calc_amount_in.go
@@ -167,7 +167,7 @@ func (p *PoolSimulator) calcMakerAssetAmountBeforeFee(order *order, makingAmount
 
 func divCeil(a, b *big.Int) *big.Int {
 	// (a + b - 1) / b
-	a = new(big.Int).Add(a, b)
-	a = new(big.Int).Sub(a, big.NewInt(1))
+	a.Add(a, b)
+	a.Sub(a, big.NewInt(1))
 	return a.Div(a, b)
 }