Every number computed, not asserted

Money math that answers for your situation, not the average person’s.

Most money advice is written once for the average reader and updated quarterly. These tools compute a different answer for every person who opens them, and the numbers you type never leave your device.

Try it on your own numbers

Zero if your state has no income tax. This is the field that decides the answer — set it to 0 and watch the winner change.

After tax, the winner is

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Compared against the 3-month Treasury at 4.19%, the real yield published by the U.S. Treasury on September 23, 2026. Runs entirely in your browser.

Five questions worth getting right

How long would your money last? Runway, and the buffer size your income actually calls for. high-yield savings Avalanche or snowball — and what does the easier one cost? Avalanche (highest rate first) is always cheaper. balance transfer Where should idle cash sit? Compared after tax, which is the only comparison that decides anything. brokerage / Treasury Are you actually on track? Measured against what you plan to spend, inflated to the year you retire — not a vague multiple of today’s salary. brokerage / advisor What can you actually afford? Two rules bind a mortgage: housing cost alone, and housing plus every other debt payment. mortgage

Why these answers differ from a comparison table

After tax

The advertised rate is the wrong number

Treasury interest is exempt from state income tax; savings interest is not. For most people who pay state tax, ranking by advertised APY puts the options in the wrong order.

Your buffer

Three to six months answers nothing

An emergency fund insures against the time taken to replace income. A contractor and a tenured salary earner need different numbers, so we compute both.

Binding constraint

Which rule is actually capping you

Affordability is limited either by your income or by your other debt. Which one decides whether paying off the car raises your ceiling at all. Nobody says.

Priced, not argued

What the easier debt plan costs

Snowball beats avalanche on motivation and loses on arithmetic. We put the gap in dollars so it is a decision you make rather than one you drift into.

Today's reference rates

Straight from the U.S. Treasury and Freddie Mac, dated, with the source named. A model trained last year cannot tell you these.

3-month Treasury · 2026-09-23

4.19%

Exempt from state and local income tax.

30-year fixed mortgage · 2026-09-17

6.95%

Freddie Mac Primary Mortgage Market Survey.

All rates

The full dataset →

Six Treasury tenors and both mortgage terms, machine-readable, with an append-only history.

Worth reading first

Your emergency fund is probably the wrong size Three to six months is the most repeated number in personal finance. It is also advice that ignores the only variable that matters. high-yield savings The 4.15% account that loses to a 3.98% one Comparison tables rank savings products by advertised rate. For most people who pay state income tax, that ranking is wrong. brokerage / Treasury What is actually capping what you can afford Two rules limit a mortgage. Lenders apply both and tell you the result. Which one is binding changes what you should do next — and it is the part nobody says out loud. mortgage
Plainly: we are a publisher, not an advisor. These are calculators and general education, built without knowledge of your circumstances. They are not personalized investment, tax, or legal advice. We earn commissions from some financial institutions when readers open accounts through our links, and that never changes what the math returns.