U-Pb dating of calcite is an emerging but rapidly growing field of application in geochronology with great potential to inform problems in landscape, basin, and mountain belt evolution, through age determination of diagenetic cements, vein mineralization, and geological formations difficult to date otherwise. In this brief, we present isotope dilution U-Pb isotope measurements on a sample of calcite (WC-1) that has been and will continue to be used as a reference material for in situ U-Pb Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICP-MS) dating, and which is suitable to be distributed to the geochronological community. We present in situ measurements using LA-ICP-MS to demonstrate the suitability of WC-1 for use as a U-Pb dating reference material, in spite of it not being isotopically homogeneous. The WC-1 calcite sample is 254.4 ± 6.4 Ma old and comprised 85–98% radiogenic lead. It presents a suitable reference material that can facilitate dating of calcite ranging in age from Precambrian to late Neogene age.