The decision desk
Not a calculator. A decision.
Answer-first frameworks for the financial decisions people actually search for: refinance, rent vs. buy, affordability, debt vs. investing and more. Every page states the framework first, then works a real example with real numbers, before pointing you to the calculator to run your own.
Mortgage decision
Should I refinance my mortgage?
The break-even math, and when a lower payment isn't actually cheaper.Housing decision
Should I rent or buy?
How your time horizon flips the cost comparison.Mortgage decision
How much house can I afford?
The budget you can approve versus the budget you should.Debt & investing decision
Should I pay down debt or invest?
Comparing a guaranteed rate against an uncertain one.Retirement decision
How much do I need to retire?
The 4% rule, and how your savings rate changes the timeline.Loan decision
How expensive is this loan, really?
Why APR — not the advertised rate — is the number that matters.Inflation scenario
What happens if inflation is 5%?
The same savings, run at 3%, 5% and 7% inflation.Investing scenario
What if my investment return is lower than I expect?
Why the return assumption matters more than most people think.Explore more resources
All calculators
Browse 40+ financial calculators organized by life event.
Visit the calculator index →Financial guides
Plain-language explanations of the formula and methodology behind every calculator.
Read the guides →Financial glossary
Learn essential terms: options Greeks, investment strategies and mechanics.
Read the glossary →