diff --git a/decimal.go b/decimal.go
index 22f49e58..475161dc 100644
--- a/decimal.go
+++ b/decimal.go
@@ -897,6 +897,7 @@ func (d Decimal) Round(places int32) Decimal {
 // Example:
 //
 //     NewFromFloat(545).RoundUp(-2).String()   // output: "600"
+//     NewFromFloat(500).RoundUp(-2).String()   // output: "500"
 //     NewFromFloat(1.1001).RoundUp(2).String() // output: "1.11"
 //     NewFromFloat(-1.454).RoundUp(1).String() // output: "-1.4"
 //
@@ -906,6 +907,10 @@ func (d Decimal) RoundUp(places int32) Decimal {
 	}
 
 	rescaled := d.rescale(-places)
+	if d.Equal(rescaled) {
+		return d
+	}
+
 	if d.value.Sign() > 0 {
 		rescaled.value.Add(rescaled.value, oneInt)
 	}
@@ -918,6 +923,7 @@ func (d Decimal) RoundUp(places int32) Decimal {
 // Example:
 //
 //     NewFromFloat(545).RoundDown(-2).String()   // output: "500"
+//     NewFromFloat(-500).RoundDown(-2).String()   // output: "-500"
 //     NewFromFloat(1.1001).RoundDown(2).String() // output: "1.1"
 //     NewFromFloat(-1.454).RoundDown(1).String() // output: "-1.5"
 //
@@ -927,6 +933,10 @@ func (d Decimal) RoundDown(places int32) Decimal {
 	}
 
 	rescaled := d.rescale(-places)
+	if d.Equal(rescaled) {
+		return d
+	}
+
 	if d.value.Sign() < 0 {
 		rescaled.value.Sub(rescaled.value, oneInt)
 	}
diff --git a/decimal_test.go b/decimal_test.go
index 7d4a38f1..72750abb 100644
--- a/decimal_test.go
+++ b/decimal_test.go
@@ -1022,6 +1022,7 @@ func TestDecimal_RoundUpAndStringFixed(t *testing.T) {
 		{"5", 1, "5", "5.0"},
 		{"5", 0, "5", ""},
 		{"500", 2, "500", "500.00"},
+		{"500", -2, "500", ""},
 		{"545", -1, "550", ""},
 		{"545", -2, "600", ""},
 		{"545", -3, "1000", ""},
@@ -1046,6 +1047,7 @@ func TestDecimal_RoundUpAndStringFixed(t *testing.T) {
 		{"-5", 1, "-5", "-5.0"},
 		{"-5", 0, "-5", ""},
 		{"-500", 2, "-500", "-500.00"},
+		{"-500", -2, "-500", ""},
 		{"-545", -1, "-540", ""},
 		{"-545", -2, "-500", ""},
 		{"-545", -3, "0", ""},
@@ -1111,6 +1113,7 @@ func TestDecimal_RoundDownAndStringFixed(t *testing.T) {
 		{"5", 1, "5", "5.0"},
 		{"5", 0, "5", ""},
 		{"500", 2, "500", "500.00"},
+		{"500", -2, "500", ""},
 		{"545", -1, "540", ""},
 		{"545", -2, "500", ""},
 		{"545", -3, "0", ""},
@@ -1135,6 +1138,7 @@ func TestDecimal_RoundDownAndStringFixed(t *testing.T) {
 		{"-5", 1, "-5", "-5.0"},
 		{"-5", 0, "-5", ""},
 		{"-500", 2, "-500", "-500.00"},
+		{"-500", -2, "-500", ""},
 		{"-545", -1, "-550", ""},
 		{"-545", -2, "-600", ""},
 		{"-545", -3, "-1000", ""},