Calculators for fees, costs and everyday money questions
Toolantern works out the numbers people usually guess at: what eBay or PayPal takes from a sale, what an AI app will cost to run each month, how long a credit card balance takes to clear. Put in your figures and you get the answer along with the math behind it. It all runs in your browser, and there is nothing to sign up for.
- Jacket sold
- $100.00
- Shipping paid by buyer
- $10.00
- eBay fees
- −$16.41
- Postage label
- −$9.00
- What you paid for it
- −$40.00
You keep$44.59
Work out your own saleAll tools
Seller & payment fees
- PayPal Fee CalculatorWhat PayPal takes from a sale, or what to charge to receive an exact amount.
- Stripe Fee CalculatorStripe's fee on any payment, with international, ACH, Terminal and add-on fees.
- Square Fee CalculatorMonthly Square fees on the Free, Plus and Premium plans, and which one pays off.
- Etsy Fee CalculatorEvery Etsy fee on a sale, plus your real profit and margin.
- eBay Fee CalculatoreBay final value fees by category, ad fees and your profit per sale.
- Card Processing Fee ComparisonStripe vs Square vs PayPal: monthly processing cost at your volume.
Personal finance
- Coast FIRE CalculatorHow much you need invested today so you could stop saving and still retire on time.
- FIRE CalculatorYour FIRE number and the age you could stop working, from income and spending.
- Credit Card Payoff CalculatorMonths to clear a card balance and the interest it costs, or the payment that clears it by a date.
- Debt Snowball vs AvalancheYour debt-free date and total interest with each method, from your own list of debts.
- 401(k) Match CalculatorYour employer match, what you're leaving behind, and the contribution rate that gets all of it.
- Roth vs TraditionalWhich account leaves more to spend in retirement, based on your tax rate now and later.
Social media
AI & API costs
Why Toolantern
Each calculator uses the rates the company itself publishes and says when they were last checked. Fees and prices change, so that date matters. The eBay, Etsy, PayPal, Stripe and Square calculators were last checked on October 7, 2026.
Under every tool there is the formula, a worked example and a short list of what it leaves out, such as negotiated rates or currency conversion. If a result looks wrong, you can follow the example and check it by hand.
Nothing you type is sent anywhere. The math happens on your own device. If there is a calculation you keep doing on the back of an envelope, send it in and it may become the next tool.
Frequently asked questions
Are Toolantern tools really free?
Yes. Every tool is free to use with no account.
Is my data private?
Calculations run in JavaScript on your own device. What you type into a tool is not sent to our servers or stored. See the privacy policy for details.
How current are the prices in the AI cost tools?
Each pricing tool shows the date its rates were last checked against the providers' official pricing pages. AI prices change often, so always confirm before committing to a budget.
Can I suggest a tool?
Please do. Use the contact page to describe the calculation you need and who it is for.