22 Free Calculators
Plan your mortgage, retirement, rent vs. buy decisions, rental income, and debt payoff. 22 free financial calculators — no sign-up required.
Core Financial
Mortgage, loans & investments
Real Estate & Specialty
Property income & veteran benefits
Gig Economy
True earnings after expenses & taxes
Planning & Decisions
Retirement & rent vs. buy
Everyday Finance & Business
Cars, savings, inflation & break-even
Most financial calculators fail their user in the same way: they return a confident-looking number built on an input the person guessed at. A mortgage payment is only as accurate as the property tax and insurance figures behind it, and a retirement projection is mostly a bet on one assumption — the return rate you typed in.
So before trusting any output on this page, get these three inputs right. They drive nearly all the variance in the result:
| If you're asking… | Use | The input that matters most |
|---|---|---|
| What will my monthly payment be? | Mortgage Calculator | Property tax rate and insurance |
| How much house can I actually afford? | Home Affordability | Existing monthly debt payments |
| Should I rent or buy? | Rent vs Buy | How many years you'll stay |
| Which debt do I pay off first? | Debt Payoff | Interest rate on each balance |
| Will I have enough to retire? | Retirement Calculator | Assumed real return rate |
| Is this rental property worth it? | Rental Cash Flow | Vacancy and maintenance reserves |
| What is my side gig really paying? | Gig Earnings | Mileage depreciation and self-employment tax |
Lenders generally want housing costs at or under 28% of gross monthly income, and total debt payments at or under 36%. Our affordability calculator applies both. A number that clears 28% but blows past 36% means existing debt — not income — is the binding constraint, and paying that down raises your budget faster than earning more.
New landlords routinely subtract only the mortgage from rent and call the difference cash flow. Realistic underwriting also reserves for vacancy (typically 5–8% of gross rent), maintenance (1% of property value per year is a common rule of thumb), capital expenditures, and property management if you won't self-manage. Those four line items frequently turn an apparent $300/month profit into a loss.
Rideshare and delivery pay is gross revenue, not take-home. Subtract the IRS standard mileage rate for vehicle cost, then 15.3% self-employment tax on the remainder, then income tax. Our gig calculators do this, which is why the effective hourly rate they return is usually far below the platform's advertised figure.
On a 30-year mortgage at 7%, you pay roughly the same amount in interest as the entire loan principal. Cutting the term to 15 years raises the monthly payment about 45% but cuts total interest by more than half — which is why the amortization table matters more than the monthly payment.
Are these financial calculators accurate?
The math is exact — these use standard amortization, compound interest, and tax formulas, and each result is checked against published references. Accuracy of the output depends entirely on your inputs. A mortgage payment computed from a guessed property tax rate will be wrong no matter how good the formula is.
Do you store the numbers I enter?
No. Every calculator here runs entirely in your browser using JavaScript. Nothing you type is transmitted to a server, logged, or saved. You can confirm this by loading a calculator, disconnecting from the internet, and using it normally — it still works.
What return rate should I use for retirement projections?
Use a real (inflation-adjusted) rate rather than a nominal one, so the answer is in today's dollars. Historically 6–7% real is a defensible assumption for a stock-heavy portfolio over multi-decade periods. If your portfolio holds significant bonds, lower it. Running the projection at 5%, 6%, and 7% tells you more than any single number.
Why does the mortgage calculator show a higher payment than my lender quoted?
Lender quotes often show principal and interest only. Our calculator includes property taxes, homeowners insurance, and PMI where applicable, because those are part of what you actually pay each month. That full figure — often called PITI — is the one to budget against.
Should I use the debt avalanche or snowball method?
Avalanche (highest interest rate first) always costs less in total interest — that is arithmetic. Snowball (smallest balance first) closes accounts sooner, which some people find more motivating. The debt payoff calculator shows both timelines and the exact dollar difference, so you can decide whether the motivational benefit is worth the cost.
Is a rental property still worth buying at current rates?
It depends almost entirely on the purchase price relative to rent, not on the rate alone. Run the cash flow calculator with honest vacancy and maintenance reserves. If the property only works with zero vacancy and no repairs, it doesn't work.
Browse Other Categories