About
This site exists to give UK small-business owners, freelancers and side-hustlers fast, trustworthy answers to the recurring number questions that quietly decide whether a business works: what do I need to sell to break even? what should I charge? how long does my cash last? is this investment actually worth it?
These are not hard questions mathematically. The problem is that the answers are usually buried — behind a sign-up wall, inside a spreadsheet you have to build yourself, or under so much filler that you can't tell whether the underlying maths is even right. The aim here is the opposite: the answer in one screen, the method shown in plain English next to it, and nothing asked of you in return.
Who this is for
People running real, small operations who need a defensible number to make a decision today — pricing a product, deciding whether to take a contract, working out if there's enough cash to make payroll, sense-checking a marketing spend. It is deliberately not aimed at accountants or analysts who already have their own models; it's for the owner who needs the same answer those models would give, without the overhead.
How the calculators are built
Every calculator runs entirely in your browser. The figures you type never leave your device — there is no account, no server, no tracking of your inputs, and nothing is stored anywhere. Each tool is a small, single-purpose program whose calculation is a pure, isolated function. That function is covered by automated tests that check it against hand-worked expected results, and the same function is what runs in your browser. In other words, the number you see on screen is the exact number that was verified in testing — not a separate implementation that might have drifted.
On every calculator page the formula is written out, followed by a fully worked numeric example using real figures, so you can reproduce the result by hand and confirm it. If a calculation can break down — a divide-by-zero, an input that has no valid answer — the tool says so explicitly instead of showing a confident but meaningless figure.
How tools are chosen
Tools are added where the maths is stable and well established (contribution- margin break-even, gross margin, return on investment, loan amortisation, and similar). Stable maths matters: it means a calculator stays correct without constant maintenance, and it means the result does not depend on rules that change from year to year or on circumstances we never asked you about.
What these tools are — and are not
They are decision-support tools that apply standard formulas to the numbers you provide. They are not financial, tax, accounting or legal advice, and they cannot see the specifics of your situation. Tax treatment in particular varies by circumstance and changes over time, which is precisely why the calculators here stay on the operational side of the line. For any decision with material financial or legal consequences, treat the output as a well-reasoned starting point and confirm it with a qualified professional who knows your full picture.
Honesty about money
Some pages link to relevant third-party software, such as bookkeeping tools. Where a link is an affiliate link we say so plainly on the page, and we only include one where the product is genuinely relevant to that calculation. An affiliate arrangement never changes a calculator's maths, its result, or what it suggests. The calculation is the product; the links are not allowed to bend it.
Feedback
If a calculator ever returns a result you believe is wrong, that matters more to us than anything else on the site — accuracy is the entire point. A contact route is published here once the site's domain and mailbox are set up.