The standard validity period for U.S. B1/B2 visas issued to Indian passport holders in Canada is ten years while allowing multiple entries. Each visit to the U.S. lets you stay six months as determined by immigration officers. The visa's usability period exists only for entering the U.S. since the stay duration is not restricted by time. After entering the US, you must check both your visa's expiration date and your I-94 record to prevent overstaying.