Run the numbers in seconds.
Margins, VAT, discounts and percentages, plus unit and live currency converters — practical tools for the everyday numbers, all in your browser.
Work out profit, margin and markup from cost and sale price.
What is the Calculators & Converters?
BYAFT Calculators & Converters is a free set of everyday calculators and converters that run instantly in your browser. Work out profit margin and markup, add or remove VAT/tax, apply discounts, find a percentage change, split a bill, calculate break-even, convert between units, or convert currencies at live rates — no spreadsheets and no sign-up.
Each tool updates as you type and shows the numbers that matter, so you can price a product, check an invoice, convert a measurement or settle a bill in seconds.
How to use the Calculators & Converters
- 1Pick a toolChoose a calculator (Margin, VAT, Discount, Percentage, Tip, Break-even) or a converter (Unit, Currency).
- 2Enter your numbersType in the figures — costs, prices, rates, quantities or amounts — using the labelled fields.
- 3Read the resultResults update instantly. No formulas to remember and nothing to calculate by hand.
What you can use it for
- Pricing a product and checking your margin and markup
- Adding or removing VAT/tax on a quote or invoice
- Working out a discount or a percentage change
- Converting units or currencies at live rates
- Splitting a bill or finding how many sales cover your costs
Frequently asked questions
Are the tools free?
Yes. Every calculator and converter is free to use with no sign-up and no limits.
What can I calculate or convert?
Profit margin and markup, VAT/tax (add or remove), discounts, percentage change, tip and bill splitting, break-even point, plus a unit converter and a live currency converter.
Are the currency rates live?
Yes. The currency converter uses live mid-market (European Central Bank) reference rates, refreshed regularly; the conversion itself runs in your browser.
What's the difference between margin and markup?
Markup is profit as a percentage of cost; margin is profit as a percentage of the selling price. The Margin & markup calculator shows both from the same figures.
Is my data sent anywhere?
The calculators and unit conversions run entirely in your browser. The currency converter fetches exchange rates from our server, but your amounts are never uploaded.
Do I need to install or sign up?
No. Everything works instantly in any modern browser with nothing to install.