All tools / Unit Converter20 inches to mm20 inches = 508 mmFormula1 inches = 25.4 mm, so 20 × 25.4 = 508Need another value? Use the full Unit ConverterOther inches → mm conversions1 inches → mm2 inches → mm3 inches → mm4 inches → mm5 inches → mm6 inches → mmReverse conversion20 mm → inchesRelated conversions1 km → miles1 miles → km1 cm → inches1 inches → cm1 cm → feet1 feet → cm