Gradient
Free financial calculators that show their work. Transparent math, live market data, and shareable deep links for every scenario you model.
Mortgage Calculator
Estimate your monthly mortgage payment with a complete breakdown of principal, interest, taxes, insurance, and PMI. Explore 15- and 30-year terms, view the full amortization schedule, and share any scenario as a deep link.
Investment Property
Cash flow projections, cap rate, cash-on-cash return, and a side-by-side comparison against index fund investing over your hold period.
Rent vs Buy
Compare the true cost of renting versus buying over time with monthly cashflows, net worth trajectories, and breakeven analysis.
Retirement
Safe withdrawal rate modeling with inflation adjustments, contribution schedules, and portfolio depletion projections.
Debt Payoff
Compare avalanche and snowball repayment strategies for up to five debts. See which saves more interest and when you'll be debt-free.
Enter your numbers
Adjust any input with sliders or text fields. Results update instantly as you explore different scenarios.
See the math
Every result includes step-by-step derivations showing the formulas, assumptions, and intermediate values used.
Share a link
All inputs are encoded in the URL. Copy the address bar to share your exact scenario — no account required.
Why Transparent Math
Most financial calculators give you a single number without explaining how they got there. That is a problem when the number influences a decision worth hundreds of thousands of dollars. Gradient takes the opposite approach: every calculation shows its work, including the formulas, the assumptions, and the step-by-step derivation that produces the result.
When you can see exactly how a monthly payment is calculated — or why one debt repayment strategy saves more interest than another — you are in a better position to question the assumptions, adjust the inputs, and make an informed choice. Financial literacy does not require a finance degree. It requires tools that respect your intelligence enough to show their reasoning.
Gradient's calculation engines are also available as public API endpoints that accept JSON and return structured results. AI assistants, spreadsheets, and custom integrations can use the same math that powers the interactive calculators on this site.