diff --git a/UBigInt.pas b/UBigInt.pas
index 7d22c07..5a31b72 100644
--- a/UBigInt.pas
+++ b/UBigInt.pas
@@ -78,6 +78,8 @@ type
     class property Zero: TBigInt read GetZero;
     function CompareTo(constref AOther: TBigInt): Integer;
     function TryToInt64(out AOutput: Int64): Boolean;
+    // TODO: ToString is currently for debug output only.
+    function ToString: string;
     class function FromInt64(const AValue: Int64): TBigInt; static;
     class function FromHexadecimalString(const AValue: string): TBigInt; static;
     class function FromBinaryString(const AValue: string): TBigInt; static;
@@ -498,6 +500,21 @@ begin
   end;
 end;
 
+function TBigInt.ToString: string;
+var
+  i: Integer;
+begin
+  if FIsNegative then
+    Result := '-'
+  else
+    Result := '';
+  for i := 0 to Length(FDigits) - 2 do
+    Result := Result + '(' + IntToStr(FDigits[i]) + ' + 2^32 * ';
+  Result := Result + IntToStr(FDigits[Length(FDigits) - 1]);
+  for i := 0 to Length(FDigits) - 2 do
+    Result := Result + ')';
+end;
+
 class function TBigInt.FromInt64(const AValue: Int64): TBigInt;
 var
   absVal: Int64;