While they recommend that you use the last pay stub for your substitute W-2, if this is not possible, your best estimate of wages and withholding is acceptable. However, you have to tell the IRS how you determined the amounts.
If you have your check amounts, you may be able to find a check calculator and back in to the withholding amounts.
You can always contact the IRS for assistance at 1-800-829-1040 and they will try to contact the employer or send you the substitute W-2 form. You can also complete this form yourself.
