Do I need a business tax extension or a personal tax extension for my single-member LLC?

It depends on what type of LLC you have. For Federal income tax purposes, a multi-member LLC is classified as a “partnership” by default (unless it specifically elects to be treated as a corporation). A multi-member LLC classified as a partnership should request a business tax extension (IRS Form 7004) to get 5 extra months to file. A multi-member LLC classified as a corporation should also request a business tax extension, which provides 6 extra months to file a corporation return. On the other hand, a single-member LLC is classified as a “disregarded entity” by default (unless it specifically elects to be treated as a corporation). When a single-member LLC is treated as a disregarded entity, that means its activities are reported on the owner’s individual income tax return (Form 1040). So if you have a single-member LLC, you only need one (1) personal tax extension (IRS Form 4868) to cover yourself and your business, which gives you 6 extra months to file your return.