Payments
Stripe Fee Calculator
Estimate Stripe processing fees and net payout, or work backwards to the amount to charge so you receive what you need.
Free tools · No sign-up
Smart Calculators for Payments, Business & AI
Calculate payment processing fees, GST, profit margins, and AI API costs with practical tools designed to help you make informed decisions.
Find a calculator
Search by name, category or what you want to work out.
Payments
All payments calculators →Work out card and wallet processing fees, net payouts and what to charge to receive a set amount.
Payments
PayPal Fee Calculator
Calculate PayPal commercial transaction fees for domestic and international payments, and the amount to invoice for a target net.
Business
All business calculators →Everyday maths for small businesses and sole traders: GST, profit, margin and markup.
Business
New Zealand GST Calculator
Add 15% GST to a price or extract GST from a GST-inclusive amount, with an adjustable rate.
Business
Profit Margin Calculator
Find gross profit, margin and markup from cost and selling price, or the price needed to hit a target margin.
AI Tools
All ai tools calculators →Estimate what large language model APIs will cost per request, per day and per month.
AI Tools
AI API Cost Calculator
Estimate AI API costs from input and output tokens, request volume and per-million-token prices for popular models.
Why use SmartCalcWorks?
Fee schedules and pricing pages are easy to misread. These tools do the arithmetic and show their working, so you can check every number.
Free to use
Every calculator is free, with no paywalls or usage limits.
Straightforward maths
Each tool shows the formula it uses, with worked examples you can check.
Transparent assumptions
Fee and price presets show their source and the date we last verified them.
Mobile-friendly
Designed for phones first, so you can check a fee at the counter or on the go.
No account needed
No sign-up, no email address, no API key. Just open a calculator and go.
Frequently asked questions
Are the calculators free?
Yes. Every calculator on SmartCalcWorks is free to use, with no account or sign-up required.
Where do the Stripe, PayPal and AI prices come from?
From the providers’ own public pricing pages. Each preset shows the date we last checked it and links to the source, so you can confirm it. If a rate isn’t right for your account, you can enter your own.
Are the results exact?
They are accurate for the formula and rates shown, rounded to the currency’s smallest unit. Real-world charges can differ because providers apply extra fees, rounding rules or account-specific pricing, so treat results as estimates.
How do I calculate GST in New Zealand?
To add 15% GST, multiply the GST-exclusive amount by 1.15. To find the GST inside an inclusive price, divide by 1.15 and subtract — or multiply by 3/23. Our GST calculator does both and lets you change the rate.
Is my data sent anywhere when I use a calculator?
No. The calculations run in your browser and the numbers you type are not sent to our servers. See the privacy policy for what information the website itself may log.
Is this financial or tax advice?
No. The calculators are general tools to help you estimate. For decisions about your business or taxes, check official guidance or speak to a qualified adviser.