Financial Calculators Suite

Select a calculator below to get started with your financial planning.

Loan Calculator

Calculate monthly payments and total interest for any loan.

Loan calculator: worked example

Default values — $10,000 loan, 5% annual interest, 5-year term — run through the standard amortization formula:

M = P × r × (1+r)ⁿ / [(1+r)ⁿ − 1]

where P = 10,000, r = monthly rate = 0.05/12 ≈ 0.0041667, and n = 60 months.

M = 10,000 × 0.0041667 × (1.0041667)^60 / [(1.0041667)^60 − 1]
  ≈ $188.71 per month

Over 60 payments that's $11,322.74 total, meaning $1,322.74 goes to interest and $10,000 to principal. The tool's amortization table shows this breaking down monthly: in month 1, of the $188.71 payment, $41.67 is interest (10,000 × 0.0041667) and $147.04 is principal; as the balance shrinks, more of each fixed payment goes to principal.

Investment calculator: how compounding is applied

This calculator compounds monthly and adds your monthly contribution at the end of each period, using two separate future-value formulas added together: FV of the lump sum principal, plus FV of an ordinary annuity for the recurring contributions. With $1,000 initial, $100/month, 7% annual return, over 10 years, the principal alone grows to roughly $2,010, and the $12,000 in total contributions (100 × 120 months) plus that growth compounds to a projected future value in the tool's output — the "Interest Earned" line isolates exactly how much came from growth versus your own deposits.

Mortgage calculator: what's estimated versus calculated

The monthly principal-and-interest figure uses the same amortization formula as the loan calculator, applied to (home price − down payment). Property tax (1.2% of home price annually) and home insurance (0.35% annually) are flat assumptions baked into the script, not pulled from any real tax authority or insurer — treat those two line items as rough estimates only, since actual local property tax rates vary widely by county and state.

Limitations shared across all three

None of the three calculators account for extra payments, rate changes mid-term, loan origination fees, or taxes on investment gains. The loan calculator's amortization table only displays the first 12 months even for longer terms, to keep the table a manageable size.