The most secure solution is to use an offline VCF Splitter Tool that runs on your own Windows OS. This means you won't be exposing any contact data online. Free web tools typically ask you to upload full vCard files, which can be a problem for sensitive data because uploading exposes it. An advanced solution like
WholeClear Split vCard Software allows you to split vCard files offline, without knowingly exposing your contacts. This
split vCard tool support all the vCard versions (2.1, 3.0, 4.0) and keep all the fields: phone numbers, emails, images, notes, etc. Whether you want to break a VCF file by contact count or specific filter, this tool processes bulk files with complete accuracy and zero data loss. For privacy-focused users, offline processing is the only reliable and professional way to handle vCard file splitting.