Start with the question
All eleven calculators
Borrowing and debt
Loan & Mortgage Calculator
Monthly payment, total interest and the full amortization schedule for a mortgage, auto, personal or student loan.
Credit Card Interest Calculator
How much interest your card charges each day from your balance, APR and due date, and what paying the minimum really costs.
Debt Payoff Planner
Avalanche against snowball on your own list of debts: total interest and the date you are debt-free under each.
Pay and jobs
Paycheck Calculator
Take-home pay after federal and state tax, Social Security, Medicare and 401(k), for all 50 states.
Salary Comparison Calculator
Which offer really pays more once taxes, commute and expenses come out of both.
Saving and retirement
Savings Calculator
How a balance grows with monthly deposits and compound interest, and how long it takes to reach a goal.
Retirement Calculator
Your projected nest egg from current savings, contributions, expected return and retirement age.
Everyday money
Percentage Calculator
X% of Y, what percent one number is of another, percentage change, and percent to decimal.
Tip Calculator
The tip and each person's share, with quick presets and a bill split for any group size.
Cars
Gas vs EV Cost Calculator
The yearly fuel cost of a gas car against an electric one from MPG, gas price and your electricity rate.
Used Car Value Calculator
Reliability by generation, cost per remaining mile and the mileage sweet spot, comparing up to three listings.
Interest is the number to watch
Most of the money decisions these calculators cover come down to interest — paying it or earning it — and to time. The same rate that makes a savings balance grow quietly makes a carried credit card balance grow against you. The Credit Card Interest Calculator shows that cost per day, which is usually more persuasive than an annual percentage. The Loan & Mortgage Calculator shows how much of each early payment goes to interest rather than the balance, and the full schedule makes it clear why extra payments early in a loan save the most.
If you are carrying more than one debt, the order you pay them in matters. The Debt Payoff Planner puts the two common strategies side by side on your real balances: avalanche targets the highest rate first and costs the least overall, snowball clears the smallest balance first for quicker wins. Seeing both with your own numbers is more useful than any rule of thumb.
What you earn, not what you’re offered
A salary figure is not what reaches your bank account. The Paycheck Calculator takes out federal and state income tax, Social Security, Medicare and retirement contributions to estimate take-home pay for any of the 50 states. When you are choosing between two offers, the Salary Comparison Calculator goes further and subtracts commute and other costs from both, because the higher number on paper is not always the better job.
Saving for later
Compound interest rewards starting early, because each year’s growth earns growth of its own. The Savings Calculator shows how a balance grows with regular deposits and how long it takes to reach a goal, and the Retirement Calculator projects a nest egg from what you have, what you add and when you plan to stop. Change one input at a time — a few more years, a slightly higher contribution — and the result shows which lever moves your future most.
Everyday numbers and your car
Not every money question is a big one. The Percentage Calculator handles discounts, raises and changes, and the Tip Calculator splits a bill fairly. For car decisions, the Gas vs EV Cost Calculator compares a year of running costs, and the Used Car Value Calculator turns a listing price and mileage into a cost per remaining mile so two cars can be compared fairly.
Your numbers stay with you
Salaries, balances and debts are exactly the kind of figures people are wary of typing into a website. All eleven calculators run entirely in your browser and make no network request with what you enter. Like every StashGrid page, they also load Google ads and analytics; the full picture is in the privacy policy. These are estimates to help you decide, not financial advice.
Questions
Which is better, the avalanche or the snowball method?
The avalanche method pays extra toward the highest-interest debt first, which minimises the total interest you pay. The snowball method pays off the smallest balance first, which gives quicker wins and can make it easier to stick with the plan. The Debt Payoff Planner runs both on your own debts side by side so you can see the difference in interest and in the date you become debt-free.
How is credit card interest calculated?
Most US cards divide the APR by 365 to get a daily rate, apply it to each day's balance, and charge the total at the end of the billing cycle. That is why a balance carried for part of a month still costs interest. Paying the full statement balance by the due date usually avoids interest on purchases because of the grace period. The Credit Card Interest Calculator shows the daily charge for your own balance and APR.
Is the paycheck calculator exact?
No calculator can match every pay stub exactly. It estimates take-home pay after federal and state income tax, Social Security, Medicare and 401(k) contributions. Your real pay also depends on your W-4 choices, local taxes and employer benefits, so treat the result as a close estimate rather than a guarantee.
How much do I need to save for retirement?
It depends on when you want to stop working, what you already have, how much you add each month and the return you expect. The Retirement Calculator projects your balance at retirement from those inputs so you can see whether you are on track and how much a change in contributions or retirement age moves the result.
Do these calculators store my numbers?
No. All eleven calculate in your browser and make no network request with what you enter, so your salary, balances and debts are never sent to StashGrid. Like every StashGrid page, they also load Google ads and analytics, as described in the privacy policy.