Why this exists
A short, honest account of what this is, where the idea came from, and what it deliberately does not try to be.
The gap it fills
There is a whole class of sums that are too small to justify a spreadsheet and too fiddly for a phone calculator. Quoting a job. Splitting a bill four ways when one person didn't drink. Working out whether a flat covers its own mortgage.
A phone calculator handles the arithmetic but forgets everything the moment you press equals, so you cannot check your working or change one figure without starting again. A spreadsheet remembers everything but demands you build it first (cells, references, formulas) before it will tell you anything at all.
What most of these sums actually want is a napkin: write the lines down in words, put the numbers next to them, and see the total. That is all this is.
Where the idea comes from
It is not an original one, and it would be strange to pretend otherwise.
Much love and inspo to Soulver, which popularised the idea of a calculator you type into like a notepad, has been doing it well since 2007, and is still the best example of the form. If you are on a Mac and want the properly powerful version of this, go and buy Soulver. It does considerably more than mine does and it is worth the money.
Several other good tools work the same way: Numi, Parsify, CalcNote, OpalCalc, NoteCalc. This is a small, free, web-based take on a well-established idea, not a new invention.
So why build another one
Because I move between machines all day, and almost all of the good ones are tied to a single platform. Soulver and Numi are Mac and iOS. OpalCalc is Windows. I work across macOS and Linux, and the sums this handles are exactly the kind you want to do right now, in the ten seconds before you forget the numbers.
A tool that only exists on one of my machines is a tool I stop reaching for. So the requirement was a browser tab: nothing to install, nothing to license per device, no sync account to set up, and the same thing on whatever I happen to be sitting in front of — including a phone. Everything else about the design follows from wanting it to load instantly and work everywhere.
I built it for myself and still use it most days. That is the whole origin story.
What is different here
The design choices that are genuinely this site's own all point the same way: towards working you hand to somebody else.
- Reference figures never get double counted. Lines marked
=(a named subtotal, a split, a ratio) are shown for reference and are deliberately excluded from the total. This is the rule the whole tool is built around, because silently counting a subtotal twice is how a quote goes out wrong. - Sheets sit side by side. Separate jobs stay separate without separate files.
- Sharing sends the working, not the answer. The whole sheet is encoded in the link, so the person receiving it can see how you got there and change a number themselves.
- Exports are built for sending. A plain-text email summary, a Markdown table, or a printed PDF, because the point of a quote is that someone else reads it.
- It runs anywhere there is a browser. macOS, Linux, Windows, a phone. No install, no per-device licence, no sync account. The same tool on whichever machine you are actually sitting at.
- It is free and needs no account. Nothing to install, and it keeps working once the page has loaded.
What it is not
It is not accounting software, and it is not advice. It does arithmetic on figures you type, and it will happily add up numbers that are wrong. Anything that matters (a quote you send, a property you buy) should be checked, and checked with a professional where the stakes justify it.
It also will not grow into a suite. There is no roadmap towards accounts, sync, teams or a subscription. The value is that it opens instantly and does one thing, and most of the ways to make money from it would cost exactly that.
How it pays for itself
There is one advertisement on the page, and that is the whole business model. No subscription, no upsell, no email capture.
The thing worth being precise about is privacy, because a calculator that quietly read your numbers would be a genuinely bad thing to put on the internet. The entire calculator runs inside your browser as plain JavaScript. There is no server to send anything to. Your sheets are stored in your own browser and stay on your device. Visitor numbers come from Cloudflare Web Analytics, which sets no cookies, stores nothing on your device and cannot follow you to another site. The advertising is Google AdSense, and consent for it is handled by Google's own certified consent tool: visitors in the EEA, UK and Switzerland get a message with a plain Do not consent button next to the accept one, and refusing means no advertising cookies are set. I would rather that message were mine, but Google requires a certified one to serve ads in Europe at all, so it is theirs.
That is not a promise about intentions. It is just how the thing is built, and you can read the page source and confirm it.
Who made it
Sum & Carry is built and run by Pete Burgess. Corrections, bugs, and arguments about whether a tip should be calculated before or after tax are all welcome at pete@sumandcarry.com.