The Hub
Financial Calculators
Every money question boils down to a formula. Pick a calculator below and get the full breakdown, not just a headline number.
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Which financial calculator do you need?
Most personal finance questions fall into one of three buckets: borrowing money, growing money, or planning for a future goal. If you're taking on debt — a mortgage, an auto loan, or a personal loan — the loan calculator tells you the fixed monthly payment and the full amortization schedule, including how extra payments cut both time and total interest. If you're trying to understand how a balance grows — a savings account, a CD, or a taxable brokerage account — the interest calculator models compound growth with your choice of compounding frequency and recurring contributions. If you're thinking further out — how much you need saved by a target retirement age, and whether your current contribution rate gets you there — the retirement calculator projects your nest egg and checks it against a monthly income goal.
The math behind every calculator here
Every calculator on this site runs the same underlying arithmetic of money over time, applied in different directions. A loan calculator starts with a lump sum today and solves for the fixed payment that pays it off, with interest, by a set date — that's the amortization formula, M = P[r(1+r)^n] / [(1+r)^n − 1]. An interest or investment calculator starts with a payment plan — a starting balance plus optional recurring deposits — and solves forward for the ending balance, using the compound interest formula A = P(1 + r/n)^(nt). A retirement calculator chains that same forward projection across decades, then works backward from a desired monthly income to figure out the nest egg size needed to support it. None of these tools require an account or store your numbers — every calculation runs instantly in your browser as you type.
Common ways people use these financial calculators
A homebuyer might use the loan calculator as a mortgage calculator to compare a 15-year term against a 30-year term at different rates, then check what an extra $200 a month toward principal would save over the life of the loan. A saver might use the interest calculator to compare a high-yield savings account against a CD, adjusting the compounding frequency to see how much of a difference daily versus monthly compounding actually makes at realistic balances. Someone in their 30s or 40s might use the retirement calculator to answer a single practical question: at my current savings rate, will I have enough by 65 to replace a target monthly income — and if not, how much more would I need to contribute starting now to close that gap?
Reading the year-by-year breakdown
Every calculator here shows its work as a year-by-year table, not just a single final number, because the path matters as much as the destination. On the loan calculator, that table shows how the split between principal and interest shifts each year as the balance shrinks. On the interest calculator, it separates deposits from interest earned so you can see how much of your growth is really compounding versus your own contributions. On the retirement calculator, it tracks your balance year by year against a target, so a shortfall shows up early enough to adjust your plan rather than as a surprise decades from now. Reading that detail, rather than skipping straight to the headline result, is usually the difference between a calculator that just satisfies curiosity and one that actually informs a decision.
Frequently asked questions
Which calculator should I start with?
Start with whichever matches your immediate decision: the loan calculator for borrowing decisions like a mortgage or auto loan, the interest calculator for growing a savings or investment balance, or the retirement calculator if you're checking whether your long-term savings plan is on track for a specific income goal.
Are these calculators free to use?
Yes, every calculator on this site is completely free, requires no sign-up, and runs entirely in your browser. Nothing you enter is sent to a server or stored anywhere.
Do these calculators account for taxes?
No, by default each calculator works with pre-tax, nominal figures. Loan payments don't include property taxes or insurance escrow; interest and retirement projections don't deduct capital gains or income tax. Build a tax adjustment into your assumed rate if you want a more conservative, after-tax estimate.
Can I use more than one calculator for the same decision?
Often, yes. For example, someone deciding whether to pay off a mortgage early or invest the difference might run the loan calculator to see interest saved from extra payments, then run the interest calculator with the same monthly amount to compare potential investment growth over the same time horizon.
What calculators are coming next?
We're building out more specialized tools, including a dedicated student loan calculator, credit card payoff calculator, mortgage refinance calculator, and net worth tracker. The three live calculators above cover the most common day-to-day math in the meantime.