Finance calculators that show their work
Twenty free calculators for the money questions that actually come up — growing savings, comparing loans, planning a payoff, converting a salary. Every tool opens with a worked example already calculated, and every page explains the formula in plain English below it.
Try it now: Compound Interest mini-calculator
Future value $0
Open the full Compound Interest Calculator → (growth chart, compounding options, full explanation)
Interest & Growth
Compound Interest Calculator
See how savings grow with compound interest and regular monthly deposits.
Simple Interest Calculator
Interest on the original principal only — the I = Prt formula, computed instantly.
APR Calculator
The rate that includes fees — compare loan offers on their true cost.
APY Calculator
Turn a stated rate into the yield you actually earn, compounding included.
CAGR Calculator
The smoothed yearly growth rate between any start and end value.
Savings Calculator
Project a starting deposit plus monthly savings, growing at interest.
Savings Goal Calculator
Work backwards from a target: the exact monthly deposit to get there on time.
Future Value Calculator
What today's money becomes later at a given rate and frequency.
Investment Calculator
Project an initial investment plus monthly contributions at a set return.
Interest Rate Calculator
Know the start, end, and time? Solve for the rate in between.
Loans & Mortgage
Loan Calculator
Monthly payment, total interest, and true total cost for any fixed-rate loan.
Mortgage Calculator
The full monthly payment: principal, interest, property tax, insurance, and PMI.
Auto Loan Calculator
Car payments figured from the real amount financed — after down payment and trade-in.
Amortization Schedule Calculator
Year-by-year table of principal, interest, and remaining balance for any loan.
Loan Payoff Calculator
Your debt-free date — and how much interest extra payments erase.
Everyday Money
Percentage Calculator
All three everyday percentage questions: X% of Y, what percent, and find the whole.
Percentage Change Calculator
Percent increase or decrease between two values, direction included.
Sales Tax Calculator
Add tax to a price — or back the tax out of a price that already includes it.
Salary to Hourly Calculator
Convert annual salary to an hourly wage (and weekly/monthly equivalents).
Tip Calculator Calculator
Tip and total with per-person split — plus a percent-off discount mode.
Money Guides
How Compound Interest Works
Interest on interest, explained — and why $5,000 plus $150 a month can become $112,987.
How Much Should You Save Each Month?
Work backwards from a goal to the exact monthly deposit it takes to get there.
How to Build an Emergency Fund
Three to six months of essentials: how to size it, where to keep it, and how long it takes.
What Is CAGR?
The compound annual growth rate — why 60% over 5 years is 9.86% a year, not 12%.
How to Pay Off a Loan Faster
The strategies that save real interest: $100 extra a month ends a loan 13 months early.
15-Year vs 30-Year Mortgage
One $350,000 loan, both terms compared — a $247,608 interest difference.
How Amortization Works
Why early payments are mostly interest, and how the split flips over the loan's life.
How Extra Payments Save Interest
$200 extra a month on a mortgage saves $109,927.51 — here is the mechanism.
APR vs APY
The true cost of borrowing vs the true yield on saving, both worked out in full.
How to Convert Salary to Hourly Pay
The 2,080-hour method for comparing salaries, hourly jobs, and freelance rates.
Why MoneyCalculatorHQ?
Most calculator sites give you a number and nothing else. MoneyCalculatorHQ is built on a different premise: a number you do not understand is a number you cannot trust. So every calculator here arrives pre-loaded with a realistic example, shows its breakdown immediately, and is followed by a complete explanation — what the concept is, the exact formula with every variable defined, a worked example whose figures match the tool above it to the cent, and honest answers to the questions people actually ask.
There are no accounts, no sign-ups, and no fees. The tools run entirely in your browser: the figures you type never leave your device. Our authors write the explanations, a reviewer checks the math, and every page carries its byline and update date so you can see exactly whose work you are reading.
One boundary we state plainly: these are educational estimate tools, not financial advice. They will make you faster and more accurate at money arithmetic — for decisions with real consequences, pair them with a qualified professional who knows your situation. Start with the Compound Interest Calculator, the Mortgage Calculator, or whichever question brought you here.