A king-size flat sheet measures 274 cm x 259 cm and fitted sheet 193 cm x 203 cm. For a California king sheet the measurements are 259 cm x 284 cm for a flat sheet and 183 cm x 213 cm for a fitted sheet so the California king sheets are narrower but longer than king-size sheets. If you are buying the sheets in a set, they will usually come with two pillowcases measuring 51 cm x 102 cm each.