diff --git a/spec/std/big/big_decimal_spec.cr b/spec/std/big/big_decimal_spec.cr
index 8708d0f5f9c9..8db3d444d8dc 100644
--- a/spec/std/big/big_decimal_spec.cr
+++ b/spec/std/big/big_decimal_spec.cr
@@ -337,36 +337,50 @@ describe BigDecimal do
     bd2 = BigDecimal.new(-123, 5)
     bd3 = BigDecimal.new(123, 0)
     bd4 = BigDecimal.new(-123, 0)
+    bd5 = "-123.000".to_big_d
+    bd6 = "-1.1".to_big_d
 
     bd1.to_i.should eq 0
     bd2.to_i.should eq 0
     bd3.to_i.should eq 123
     bd4.to_i.should eq -123
+    bd5.to_i.should eq -123
+    bd6.to_i.should eq -1
 
     bd1.to_u.should eq 0
     bd2.to_u.should eq 0
     bd3.to_u.should eq 123
     bd4.to_u.should eq 123
+    bd5.to_u.should eq 123
+    bd6.to_u.should eq 1
 
     bd1.to_f.should eq 0.00123
     bd2.to_f.should eq -0.00123
     bd3.to_f.should eq 123.0
     bd4.to_f.should eq -123.0
+    bd5.to_f.should eq -123.0
+    bd6.to_f.should eq -1.1
 
     bd1.to_i!.should eq 0
     bd2.to_i!.should eq 0
     bd3.to_i!.should eq 123
     bd4.to_i!.should eq -123
+    bd5.to_i!.should eq -123
+    bd6.to_i!.should eq -1
 
     bd1.to_u!.should eq 0
     bd2.to_u!.should eq 0
     bd3.to_u!.should eq 123
     bd4.to_u!.should eq 123
+    bd5.to_u!.should eq 123
+    bd6.to_u!.should eq 1
 
     bd1.to_f!.should eq 0.00123
     bd2.to_f!.should eq -0.00123
     bd3.to_f!.should eq 123.0
     bd4.to_f!.should eq -123.0
+    bd5.to_f!.should eq -123.0
+    bd6.to_f!.should eq -1.1
   end
 
   it "hashes" do
@@ -435,6 +449,9 @@ describe BigDecimal do
 
     it { -2.01.to_big_d.ceil.should eq(-2) }
     it { -2.91.to_big_d.ceil.should eq(-2) }
+
+    it { "-123.000".to_big_d.ceil.value.should eq(-123) }
+    it { "-1.1".to_big_d.ceil.value.should eq(-1) }
   end
 
   describe "#floor" do
@@ -445,6 +462,9 @@ describe BigDecimal do
     it { 2.11.to_big_d.floor.should eq(2) }
     it { 2.91.to_big_d.floor.should eq(2) }
     it { -2.91.to_big_d.floor.should eq(-3) }
+
+    it { "-123.000".to_big_d.floor.value.should eq(-123) }
+    it { "-1.1".to_big_d.floor.value.should eq(-2) }
   end
 
   describe "#trunc" do
diff --git a/src/big/big_decimal.cr b/src/big/big_decimal.cr
index 611d5e87c568..be67bb744938 100644
--- a/src/big/big_decimal.cr
+++ b/src/big/big_decimal.cr
@@ -260,7 +260,8 @@ struct BigDecimal < Number
     in_scale(new_scale.scale)
   end
 
-  private def in_scale(new_scale : UInt64) : BigDecimal
+  # :nodoc:
+  def in_scale(new_scale : UInt64) : BigDecimal
     if @value == 0
       BigDecimal.new(0.to_big_i, new_scale)
     elsif @scale > new_scale
@@ -291,7 +292,8 @@ struct BigDecimal < Number
   def ceil : BigDecimal
     mask = power_ten_to(@scale)
     diff = (mask - @value % mask) % mask
-    (self + BigDecimal.new(diff, @scale))
+    value = self + BigDecimal.new(diff, @scale)
+    value.in_scale(0)
   end
 
   def floor : BigDecimal
@@ -331,11 +333,7 @@ struct BigDecimal < Number
 
   # Converts to `BigInt`. Truncates anything on the right side of the decimal point.
   def to_big_i
-    if self >= 0
-      self.floor.value
-    else
-      self.ceil.value
-    end
+    trunc.value
   end
 
   # Converts to `BigFloat`.