You'll need to use a gauge like this:
Or take them to a brake shop and have them measured.
2015 BMW M4— Mineral White on Sakhir Orange/Black DCT
2012 BMW S1000RR — Racing Red/Alpine White
2009 BMW M3 Coupe — Alpine White on Fox Red, DCT - Sold
2003 BMW M3 — Carbon Black on Black, 6MT - Sold
1995 BMW M3 Coupe — Cosmos Black on Black - Sold