Free calculators
for the math you actually run.
AI subscription cost-of-ownership, live HYSA APY comparison, inflation-adjusted real returns. No signup, no advice — just the numbers, with our methodology in plain text.
The calculators
Each tool runs in your browser. No data leaves the page.
AI Subscription Cost
Add up what your stack of AI subscriptions costs per year — across paid seats, API spend, and add-ons.
AI Free Tier Limits
What you can actually do without paying. Limits, models, and training-data policy across 14 major AI tools.
API Pricing Reference
Per-million-token cost across GPT-4o, Claude 3.5, Gemini 1.5, Mistral. Input, output, and context window in one table.
AI Model Timeline
When each major AI model shipped — vendor, context window, and what was notable. From ChatGPT 2022 through latest.
Loan Amortization
Monthly payment, total interest, and balance schedule for any fixed-rate loan. Mortgages, auto, personal.
HYSA APY Comparison
Side-by-side APY, fees, and signup bonuses across the top online banks and neobanks. Live data.
Inflation Real Return
Convert nominal returns or APYs into real, inflation-adjusted purchasing power over your time horizon.
Compound Interest
See how a balance grows over time with compounding. Adjust contributions, return rate, frequency.
Savings Goal
Enter a target amount and timeline; get the monthly contribution needed at current rates.
Goal Tracker
Track progress toward a savings goal as APY rates change. Live HYSA-rate aware.
Emergency Fund
Calculate how big your emergency fund should be based on monthly expenses and risk profile.
Effective APY
Convert any nominal APR into a true APY based on compounding frequency. Compare daily, monthly, quarterly side-by-side.
Mortgage Affordability
Find the maximum home price you can afford based on income, debts, down payment, and the 28/36 housing-cost rules.
Rule of 72
Estimate how long it takes to double your money — Rule of 72 shortcut alongside the exact compound-interest answer.
What this site is and isn't
What we publish
Free calculators that take your inputs and return a concrete number. The math, the sources, and the assumptions are documented on every tool page. We update vendor pricing and rate data on a published cadence.
What we don't
Stock picks, retirement-strategy recommendations, tax-planning advice, or paid placements. Run your own numbers; if the decision is consequential, take them to a licensed professional.