All tools / Unit Converter4 inches to mm4 inches = 101.6 mmFormula1 inches = 25.4 mm, so 4 × 25.4 = 101.6Need another value? Use the full Unit ConverterOther inches → mm conversionsinchesmm1 inches25.4 mm2 inches50.8 mm3 inches76.2 mm5 inches127 mm6 inches152.4 mm7 inches177.8 mmReverse conversion4 mm → inchesRelated conversions1 km → miles1 miles → km1 cm → inches1 inches → cm1 cm → feet1 feet → cm