SigFigs[numString_String] := Module[
  {chkString, numNum, fractionLength, firstPosition, sigFigs},
  (* Created by NJG, Sat Mar 22 2008 *)
  (* Updated by NJG, Sun 28 Aug 2011 *)

  chkString = numString; (* must make copy to alter input string *)
  chkString = StringReplace[chkString, ","->""]; (* toss commas *)

  numNum = ToExpression[chkString];
  If[! NumberQ[numNum], Return["Error: "<>chkString<>" is not a number."]];

  If[numNum < 1, (* DECIMAL fraction *)
   splitNum = StringSplit[numString, "."];
   fractionLength = StringLength[splitNum[[2]]];
   firstPosition = Ceiling[Abs[Log[10, numNum]]];
   sigFigs = (fractionLength + 1) - firstPosition;
  ];

  If[numNum >= 1, 
   If[StringMatchQ[numString, "*.*"],
    (* DECIMAL number *)
    chkString=StringReplace[chkString, "."->""]; (* toss decimal pt *)
    sigFigs = StringLength[chkString],
    (* Else INTEGER number *)
    noTrailZeros = NumberForm[ToExpression[StringJoin[".", chkString]], 
      StringLength[chkString]];
    splitNum = StringSplit[ToString[noTrailZeros], "."];
    sigFigs = StringLength[splitNum[[2]]]
   ]
  ];

  Return[sigFigs]
]