HashOnClick

HashOnClick is a Windows context menu tool that can provide the hash values of files. To get hash code, simply right click on the file, select "Calculate Hash Value", and click on the required hash algorith (MD5, SHA1, CRC32).

You can select multiple files to get hash codes of all of them together. If any of the codes are preset in Windows clipboard, they are displayed in blue colour; this feature is quite useful for finding duplicate files.