One running tax number, kept current
Bring your income in, one engine computes it, and your estimate stays live all year. Try the live number yourself below — estimates to plan with, not tax advice.
The whole loop at a glance
Your income
Every kind, in one place
Spaife’s engine
One calculation across all of it
One live number
Updates as you earn — with flags
Every kind of income, in one place
Most people now earn across several places at once, and each kind of income carries its own tax rules — the mix that breaks software built for the simple W-2 world. Spaife handles all of it.
Three ways to get it in
Connect — read-only
Link a broker, bank, or exchange. Spaife reads records; it never moves money.
Upload a CSV
Drop in an export from your broker, exchange, or sportsbook.
Enter manually
Add anything by hand — a 1099, a side gig, a prediction-market win.
Direct integrations are rolling out; you can always import by CSV or by hand in the meantime.
All of it collapses into a single estimate
The engine doesn't just total things up — it watches for the situations generic calculators quietly miss. A few of them:
W-4 Withholding Tuner
See whether you’re over- or under-withholding, and adjust before year-end instead of after.
CatchesYour paycheck withholding won’t cover your side income — Spaife shows the gap now, so you fix your W-4 instead of owing in April.
Wash-Sale Guard & TLH
Spot chances to use investment losses to lower your tax — while watching the 30-day wash-sale window.
CatchesYou sell a stock at a loss and rebuy within 30 days — the loss is disallowed. Spaife flags the wash sale before you trade.
Session Netting Optimizer
Group wins and losses by session to estimate the impact of your betting.
CatchesWin $10k and lose $10k betting: naive tools treat the full $10k as income. Spaife groups by session so the estimate reflects reality.
Multi-State Nexus Engine
See if a side gig or a move means you may owe tax in more than one state.
CatchesYou took a remote contract in another state — you may owe tax there too. Spaife flags the second-state return.
Honest about it: the engine produces estimates to help you plan — simplified while we're building, and never a substitute for a tax professional.
Watch your number move — and ask "what if"
Add income and the estimate recomputes instantly. Thinking about selling a stock at a loss, or itemizing instead of taking the standard deduction? Run the what-if and see the impact now — not next April. Try it:
Add income · run a what-if
12.9% effective · on $91,000 income
Estimated federal tax $11,773 on $91,000 of income, a 12.9 percent effective rate.Phantom income: you're taxed on the $10,000 sportsbook win even if you broke even. Try itemizing to deduct the losses →
Illustrative only — a simplified estimate to show how the number reacts, not tax advice. The real engine uses your actual records and full rules.
Want this running on your own income?
Free during early access · Estimates, not tax advice