About SavingsGoal

SavingsGoal publishes free personal finance calculators that show their working: the formula, the assumptions, and the limits of what the output can tell you.

Why this site exists

Most online financial calculators return a number and nothing else. You cannot tell whether interest compounded monthly or annually, whether contributions landed at the start or the end of the period, or whether the projection was adjusted for inflation. Those choices routinely move the answer by tens of thousands of dollars over a long horizon.

Every tool here publishes the equation it evaluates and states its assumptions in plain language next to the result. Where a simplification is made — ignoring taxes, assuming a constant rate of return — it is named rather than buried.

Editorial and review process

Calculators are written and reviewed by the SavingsGoal Team, a small group with 10+ years of combined experience in personal finance and fintech. Each tool goes through the same sequence before publication:

1. The underlying formula is sourced from standard financial mathematics — future value of an annuity, the Fisher equation, present-value discounting — and documented on the page itself.
2. The implementation is checked against independently computed reference values across a spread of inputs, including the boundary cases of a zero interest rate and a zero contribution.
3. Explanatory copy is reviewed for accuracy and for the distinction between arithmetic fact and financial opinion.
4. Pages carry a visible last-updated date and are re-reviewed when prevailing rates or the tax treatment of an account type change materially.

Methodology and sources

Financial formulas used across the site come from standard time-value-of- money mathematics as taught in corporate finance. Historical return ranges quoted in the guides reflect long-run broad-market index performance; prevailing savings and certificate-of-deposit yields reflect published rates at the time of each page's last review. Rate figures are illustrative reference points, not offers, quotes, or forecasts.

Primary sources:

• SEC Investor.gov — compound interest and time-value-of-money mechanics underlying the compound interest, savings goal, and Rule of 72 calculators.
• SEC Investor.gov — Dollar-Cost Averaging — the investing strategy behind the dollar-cost averaging calculator.
• SEC Investor.gov — Savings Goal Calculator — the same savings-goal math used by the savings goal timeline calculator.
• Consumer Financial Protection Bureau — the debt-to-income ratio used by the 28/36-rule house affordability calculator.
• Consumer Financial Protection Bureau — private mortgage insurance (PMI) conventions used by the mortgage payment and house affordability calculators.
• Consumer Financial Protection Bureau — Regulation Z repayment-disclosure conventions behind the minimum-payment formula used by the credit card payoff calculator.
• Federal Reserve Bank of St. Louis (FRED) — S&P 500 index data behind the long-run broad-market return ranges cited in the guides.
• FDIC National Rates and Rate Caps — the published deposit-rate context behind the high-yield savings and certificate-of-deposit calculators.

How the calculations run

Every calculation executes in your browser using JavaScript. Nothing you type is transmitted to a server, logged, or stored. Inputs are mirrored into the page's query string so a result can be bookmarked or shared as a link — that link contains your figures, so treat it as you would any other personal information before sending it to someone.

How the site is funded

SavingsGoal is funded by display advertising. We do not accept payment for recommendations, do not run affiliate links to banks or brokerages, and do not rank products. Advertisers have no influence over the content of any calculator or guide. Details of the ad technology used are set out in theprivacy policy.

Browse the calculators

Every tool on the site works the same way — the formula, assumptions, and worked examples are on the page alongside the calculator. Start with the full index of every calculator, or jump straight to a topic:Budgeting ·Savings ·Compound Growth ·Debt Payoff ·Mortgage ·Retirement. New to budgeting? Try the 50/30/20 calculator, the compound interest calculator, or the savings goal timeline. Thesitemap lists every page in one flat index for crawlers and humans alike.

Corrections

If a calculation looks wrong, we want to know. Email hello@savingsgoal.org with the page, the inputs you used, and the result you expected. Confirmed errors are corrected and the page's updated date revised. See the contact page for what else we can help with.