You can now check USCIS processing times online at the USCIS web site. All you need to enter is your form number, and the office processing your case. USCIS has made processing times easier to understand and provide a more realistic date range.
The processing time range is how long it is taking for USCIS to process your type of case from the date they received it. USCIS processes cases in the order they receive them, and they normally update this information monthly. The estimated time range displayed is based on data captured over the last two months.
For more information about case processing times and how to reading your receipt notice, view the USCIS web page, Case Processing Times.