I got tired of doing rough napkin math on whether to elect S-Corp for my LLC, so I built a calculator over the weekend.

Most tools I found either ignore state/city taxes, charge you for the answer, or require creating an account to see anything useful. TakeHome runs entirely in your browser (no sign-up, no analytics, no server-side storage) and updates every number in real time as you drag sliders.

What it models: - LLC self-employment tax vs. S-Corp FICA on W-2 salary

- QBI deduction (Section 199A) with SSTB phase-out

- Solo 401(k) with SECURE 2.0 rules (traditional/Roth/split, catch-up limits by age bracket)

- Self-employed health insurance deduction

- S-Corp admin/compliance cost comparison

- NY State income tax, franchise tax, PTET

- NYC UBT (LLC), GCT (S-Corp), PIT with IT-219 credit

You can save scenarios, compare any two side by side (it shows exactly which inputs differ and the dollar impact), and run multi-dimensional "what-if" experiments.

There's also an AI mode where you describe a scenario in plain English and it generates the experiment for you.

The tax engine is ~2,000 lines of TypeScript with no external dependencies. Stack is React 19, MobX, Tailwind v4, deployed on Cloudflare Workers. AI feature uses Claude Haiku.

Caveats: NY/NYC taxes are fully modeled; for other jurisdictions it's directionally correct at the federal level (SE vs. FICA, QBI, 401k analysis are location-independent). Standard deduction assumed. SSTB assumed for QBI. Not financial advice, treat it as prep for a conversation with your CPA.

I've added detailed tooltips on every computed line item with formulas, IRS code references, and source links. Every number shows its work.

Interested in feedback, especially if you spot tax logic errors. Also curious whether I should prioritize other states (CA, TX, FL?) or itemized deduction support next.

https://takehome.money