Calculators
Free, no signup, nothing stored — every one runs in your browser and shows the formula it uses, so you can check the arithmetic yourself.
Available
Portfolio overlap
Four funds is not four investments. See what your holdings actually add up to once the overlap between them is accounted for.
Compound growth
What a starting balance plus monthly contributions becomes over time, and how much of the result is growth rather than deposits.
Fund comparison
Two funds, side by side, by return and cost — and what a fraction of a percent a year compounds into.
Roth vs traditional
Same contribution, taxed now or taxed later — compared on spendable money after tax, using your own rates.
In progress
Annual fee break-even
How much category spending a card's fee actually requires before the rewards clear it.
Savings rate to retirement
How many working years a given savings rate implies, independent of income.