A king size mattress measures 76 inches wide by 80 inches long. While the king size is the widest standard mattress size, it’s not the longest. Queen and king beds have the same length of 80”, and California king beds are longer, measuring 72” x 84”. Opt for the longer Cali king if you’re tall or if you have pets curl up at your feet during the night.
There are mattresses wider than a standard king, including the Alaska king, Texas king, and Wyoming king. These beds measure 108” x 108”, 80” x 98”, and 84” x 84”, respectively. However, most mattress brands don’t offer these specialty sizes.