Finance Calculators
🧮 Finance Calculators
Click any calculator to open it. Inputs on the left update results on the right instantly. Download your results as CSV or PDF.
Budget planner
Income vs expenses, surplus or deficit
Mortgage
Monthly payment, interest, amortization
Investment comparison
Compare growth across savings, bonds, stocks, real estate, crypto
Compound interest
How your money grows over time
Rent vs buy
True 5-year cost comparison
Budget Planner
Track income and expenses, find your monthly surplus or deficit
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Monthly income
$
$
Monthly expenses
$
$
$
$
$
$
Total monthly income$6,500
Total monthly expenses$3,500
Savings rate46%
Monthly surplus / deficit$3,000
Expense breakdown
📚 Understanding the terms
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Inputs
Monthly incomeAll money coming in each month. Enter take-home pay (after taxes), not your gross salary.
Monthly expensesEverything you spend — fixed (rent, loans) and variable (groceries, dining). Most people underestimate expenses.
Savings as an expenseTreat savings like a bill — pay yourself first. Include 401k contributions and emergency fund deposits as expense lines.
Results
SurplusIncome exceeds expenses. Money left over to save, invest, or pay down debt.
DeficitExpenses exceed income. Spending more than you earn — unsustainable without cutting costs or increasing income.
Savings ratePercentage of income going to savings or left as surplus. Financial experts recommend saving at least 20% of take-home pay.
Expense breakdownEach expense as a percentage of total spending. Shows where to focus if you want to cut costs.
Mortgage Calculator
Monthly payment, total interest, amortization
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Loan details
$
$
%
%
Additional costs
$
$
$
Total monthly payment
$2,632
Principal + interest + taxes + insurance + HOA
Principal & interest
$2,088
Tax & insurance
$517
Loan amount
$320,000
Total interest paid
$431,676
Total cost of home
$751,676
HOA (monthly)
$0
Payment breakdown
Amortization — first 12 months
Mo.
Payment
Principal
Interest
Balance
Estimates only. Check live mortgage rates →
📚 Understanding the terms
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Inputs
Home priceThe total purchase price of the home you want to buy.
Down paymentCash paid upfront. The rest becomes your loan. Higher down payment = smaller loan and lower monthly payments.
Down payment %Your down payment as a percentage of the home price. Below 20% usually means paying PMI (private mortgage insurance), which adds to your monthly cost.
Loan termHow many years to repay the loan. 30 years = lower payments but far more interest. 15 years = higher payments but much less interest total.
Interest rateWhat your lender charges annually to borrow. Even a 0.5% difference can save or cost tens of thousands over 30 years.
Property taxLocal government tax based on your home's value. Your lender collects it monthly in an escrow account and pays it when due.
Home insuranceProtects against damage and theft. Lenders require it. National average is $1,200-$2,000 per year.
HOA feeMonthly fee in condos and planned communities for shared amenities. Enter 0 if your home doesn't have one.
Results
Total monthly paymentEverything you pay monthly — principal, interest, taxes, insurance, and HOA. The real number to compare against your budget.
Principal & interestThe core mortgage payment. Principal reduces what you owe. Interest is the lender's fee. Most early payments are interest — this shifts over time.
Total interest paidAll interest over the life of the loan. On a 30-year mortgage, this often exceeds the original home price.
Total cost of homeHome price plus all interest. The true cost of buying — much more than the purchase price alone.
Amortization table
PrincipalPortion reducing your loan balance. Starts small, grows larger every month.
InterestPortion going to your lender. Dominates early payments. Extra early payments save significantly over the loan life.
BalanceWhat you still owe after each payment. Drops slowly in early years — normal for all fixed-rate mortgages.
Investment Comparison
See how the same money grows differently depending on where you put it
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Your investment
$
$
What we're comparing — rates are editable
Projected value after 15 years
Growth comparison
Based on historical average annual returns. Past performance does not guarantee future results. Higher returns generally come with higher risk and volatility. Check live Bond Yields & Mortgage Rate →
📚 Understanding the terms
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Inputs
Amount to investThe lump sum you have today to put into an investment.
Monthly additionOptional ongoing contribution. Regular investing, even small amounts, compounds significantly over long time horizons.
Time horizonHow many years before you need the money. Longer horizons favor higher-growth, higher-volatility options since there is more time to recover from downturns.
Interest rate (% field)The small editable box next to each vehicle below. Pre-filled with a default average, but you can change it to test your own assumption — a different bond yield, a more conservative stock return, or your actual savings rate.
The 5 vehicles compared — defaults shown, all rates editable
Savings accountDefault 0.5% matches the FDIC national average for traditional savings accounts. High-yield savings accounts currently offer closer to 4%, a different product worth shopping for separately. Edit the rate to match your actual account.
Bonds (10-Year Treasury)Default 4% reflects a recent multi-year average. The actual yield moves daily and has ranged roughly 1% to 6% over the past 25 years. Edit to today's rate using the live dashboard link below, or your own assumption.
Real estate (historical average)Default 6% approximates long-run U.S. home price appreciation. Excludes rental income, maintenance, and transaction costs, and varies enormously by location. Edit to reflect your local market.
S&P 500 (historical average)Default 10% is the commonly cited long-run average including dividends, before inflation. Year to year returns vary enormously, including sharply negative years. Edit to use an inflation-adjusted (~7%) assumption if you prefer.
Crypto (illustrative)Default 15% is shown for comparison only and is not a real average — cryptocurrency has no stable long-term return. Treat any number here as a rough illustration of high volatility, not a forecast.
Results
Projected valueWhat your investment could grow to under each vehicle's historical average return, assuming the rate holds steady. Real results will vary year to year.
Risk levelA general guide, not a guarantee. Higher potential return usually comes with higher potential for loss, especially over short time periods.
Why the gap looks so largeSmall differences in annual return compound dramatically over long periods. This is the same compounding effect from the Compound Interest calculator above, just applied to different rates.
Compound Interest Calculator
See how your savings or investments grow over time
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Your investment details
$
$
%
Final balance
$0
After 20 years
Starting amount
$10,000
Total contributions
$120,000
Interest earned (money your money made)
$0
Growth milestones
Returns not guaranteed. Assumes fixed rate, excludes taxes and inflation.
📚 Understanding the terms
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Inputs
Starting amountMoney you have today to invest. Even a small amount grows significantly over time with compounding.
Contribution amountHow much you add at each interval you select below. Consistency matters more than the starting balance; small regular contributions have an enormous impact over time.
Contribution frequencyHow often you add the contribution amount — weekly, biweekly (every 2 weeks), monthly, quarterly, or annually. Interest also compounds on this same schedule, so more frequent contributions and compounding both modestly increase your final balance.
Annual interest rateExpected yearly return. The S&P 500 has historically returned ~7% after inflation. Savings accounts currently offer 4-5%.
Years to growTime invested. This is the most powerful factor — doubling your investment period can more than double your final balance.
Results
Final balanceTotal value at the end — starting amount, all contributions, and all interest earned combined.
Interest earnedMoney your money made for you without working. The longer you wait, the larger this becomes relative to your own contributions.
CompoundingEarning interest on your interest. Year 1 you earn interest on your balance. Year 2 on a larger balance. This snowball effect accelerates dramatically over decades.
Rent vs Buy Calculator
Compare the true 5-year cost of renting versus buying
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🏠 Buying
$
%
%
$
$
%
🏢 Renting
$
%
$
%
5-year net cost of buying
$0
After equity & appreciation
5-year net cost of renting
$0
After investment gain
Calculating...
Home value in 5 years
$0
Equity built
$0
Total rent paid
$0
Investment gain on down payment
$0
5-year comparison. Assumes 3% closing costs. Excludes maintenance and tax deductions. Check live mortgage rates →
📚 Understanding the terms
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Buying inputs
Home appreciation rateHow much the home's value grows per year. U.S. historical average is 3-4% annually, varies significantly by location.
Closing costsFees paid when purchasing — typically 2-5% of price. This calculator uses 3% automatically. A significant upfront cost that takes time to recoup.
Renting inputs
Annual rent increaseHow much rent rises each year. National average ~3%, varies by market. Rising rent erodes renting's financial advantage over time.
Investment return on down paymentIf renting, you keep the down payment and can invest it. The S&P 500 has returned ~7% annually historically.
Results
Net cost of buyingTotal buying costs minus equity and appreciation gained. Lower number = buying was more financially advantageous.
Net cost of rentingTotal rent paid minus investment gain on down payment kept. Lower number = renting was more financially advantageous.
Equity builtHow much of the home you own after 5 years — down payment + principal paid + appreciation. Wealth renters don't accumulate.
The bigger pictureBuying offers stability and forced savings through equity. Renting offers flexibility and lower upfront cost. Run the numbers, but factor in your life goals too.