1040 vs 1120 tax prep: what's the difference?
Definition Form 1040 is the U.S. individual income tax return; the 1120 series covers corporations, 1120 for C-corporations and 1120-S for S-corporations, while Form 1065 covers partnerships. A 1040 reports a person's income, deductions, and credits; an 1120-S or 1065 reports a business's income and passes it through to owners on a Schedule K-1, which then flows onto their 1040.
The practical difference for a firm is complexity and data flow: business returns require a clean set of books first, and pass-through returns connect to the owners' individual returns. Preparing them well means the bookkeeping and the returns are connected.
LucaLedger prepares 1040, 1120, 1120-S, and 1065 across 46 states + DC, with the books feeding the return.