All calculators
Numbers-first utilities: live HYSA rates, compound math, inflation-adjusted real returns, AI subscription cost analysis. No sign-ups, no paywalls, no “what to buy” advice — just the math, in your browser.
AI
4 toolsAI Tool Free Tier Limits
What you can actually do without paying. Free-tier limits, model access, training-data policy across 14 major AI tools.
Open tool →AI Model API Pricing
Per-million-token cost across GPT-4o, Claude 3.5, Gemini 1.5, Mistral. Input cost, output cost, and context window.
Open tool →AI Model Release Timeline
When each major AI model shipped — vendor, context window, and what was notable about the release.
Open tool →AI Subscription Total Cost Calculator
Add up what your stack of AI subscriptions actually costs per year — across paid seats, usage caps, and hidden API spend — and see the per-month equivalent versus a single power-user seat.
Open tool →Rates
1 toolMath
6 toolsCompound Interest Calculator
See how a balance grows over time with compounding. Adjust starting amount, monthly contributions, return rate, and frequency.
Open tool →Inflation-Adjusted Real Return Calculator
Convert nominal returns or APYs into real, inflation-adjusted purchasing power. See what your money actually buys after CPI erosion over your time horizon.
Open tool →Loan Amortization Calculator
Get the monthly payment, total interest, and balance schedule for any fixed-rate loan. Useful for mortgages, auto loans, and personal loans — runs in your browser with no signup.
Open tool →Effective APY Calculator
Convert any quoted nominal interest rate into a true Annual Percentage Yield (APY) based on how often it compounds. See exactly how 4.50% APR with monthly compounding compares to 4.50% APR daily.
Open tool →Rule of 72 — Doubling Time Calculator
Estimate how long it takes for an investment or balance to double at a given annual return rate. Compare the Rule of 72 shortcut against the exact compound-interest answer side-by-side.
Open tool →CAGR Calculator — Compound Annual Growth Rate
Compute the Compound Annual Growth Rate (CAGR) between any starting and ending value over a given period. Compare CAGR against the total return, the Rule of 72 doubling shortcut, and the exact doubling time.
Open tool →Planning
3 toolsPersonal Savings Goal Tracker
Track progress toward a savings goal as the top APY changes. Local-only — your goal is stored in your browser.
Open tool →Savings Goal Calculator
Figure out how much to save each month to reach your financial goal, factoring in your current savings and expected returns.
Open tool →Mortgage Affordability Calculator
Find the maximum home price you can afford based on income, existing debts, down payment, mortgage rate, and the standard 28/36 housing-cost rules. Includes property tax and insurance in the math.
Open tool →Savings
1 toolHow these tools work
Every calculator runs entirely in your browser — no inputs leave the page, no account required. Data sources, comparison framework, and verification cadence are documented in our Methodology. Pre-publication standards in our Editorial Standards.