The four basic pillow sizes are standard, queen, king and euro. A standard pillow measures 20 by 26 inches, a queen measures 20 by 30 inches, a king measures 20 by 36 inches, and a euro measures 26 by 26 inches.
Pillows are further categorized by degree of firmness. Soft pillows provide light support and are recommended for those who prefer to sleep on their stomachs. For those who sleep on their backs, medium-support pillows effectively hold the head in alignment with the body and allow for comfortable sleep. For people who sleep on their sides, firm and super firm pillows provide the support required to hold the head and neck at a relaxed angle during sleep.