King-size pillows are larger than standard pillows, measuring approximately 20 inches by 36 inches. They are designed to provide ample support and comfort for those who sleep on a king-size bed or prefer extra space while resting. These pillows can be filled with various materials, including memory foam, down, or synthetic fibers, catering to different sleep preferences. King-size pillows are also popular for decorative purposes, often used as back support on larger beds or sofas.