Why this exists
What this is, why I built it, and what it doesn't try to be.
The gap it fills
Some math is too small for a spreadsheet and too fussy for a phone calculator. Working out what to quote a client. Splitting a check four ways when one person didn't drink. Seeing whether the rent on a place would cover its mortgage.
A phone calculator does the arithmetic, then forgets it the second you hit equals. You can't check your work, and you can't change one number without starting over. A spreadsheet remembers everything, but you have to build it first — cells, references, formulas — before it tells you anything.
Most of this wants a napkin. Write the lines down in words, put the numbers next to them, see the total.
Why I built it
Typing into a calculator like it's a notepad isn't a new idea. Soulver, Numi, CalcNote and OpalCalc are all good at it, and I took the inspiration happily. The problem was using one everywhere. The best of them are locked to a single platform, and I move between macOS, Linux and a phone all day. The ones that ran in a browser were either too thin to be useful or fussier than the math I was doing, and none of them were much to look at.
A tool that only exists on one of my machines is a tool I stop reaching for. So it had to be a browser tab: nothing to install, no license per device, no sync account to set up, and the same thing on whatever I'm sitting in front of. Everything else about the design comes out of wanting it to load fast and work everywhere.
I built it for myself and I still use it most days.
What's different here
The design all points the same way: toward work you can hand to someone else.
- Reference figures never get double counted. Lines marked
=— a named subtotal, a split, a ratio — are shown for reference and left out of the total. It's the rule the whole tool is built around, because 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 work, not the answer. The whole sheet is encoded in the link, so whoever gets 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's a browser. macOS, Linux, Windows, a phone. No install, no per-device license, no sync account.
- It's free and needs no account. Nothing to install, and it keeps working once the page has loaded.
What it isn't
It isn't accounting software and it isn't advice. It does arithmetic on the numbers you type, and it'll 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 when the stakes are high enough.
It also won't grow into a suite. There's no roadmap toward 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
One ad on the page. That's the whole business model. No subscription, no upsell, no email capture.
Privacy is the part worth being precise about, because a calculator that quietly read your numbers would be a bad thing to put on the internet. The whole calculator runs in your browser as plain JavaScript. There's no server to send anything to. Your sheets are stored in your own browser and stay on your device. Visitor counts come from Cloudflare Web Analytics, which sets no cookies, stores nothing on your device, and can't follow you to another site. The ads are Google AdSense, and consent for them 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 get set. I'd rather that message were mine, but Google requires a certified one to serve ads in Europe at all, so it's theirs.
None of that is a promise about intentions. It's how the thing is built, and you can read the page source and check.
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 all go to pete@sumandcarry.com.