Check the Journal Citation Reports (JCR) to find the most recent impact factors of journals.
Journal Citation Reports or JCR (just as Web of Science a product of Thomson Reuters) lists impact factors of journals. You can search for a specific journal or a group of journals by subject. Please use Chrome or Firefox. JCR does not perform well in Internet Explorer.
Search by subject: choose a subject from the list. Close the pop-up. Click on 'submit' at the left bottom of the page.