The scratchpad that does the math for you

Type your numbers the way you'd scribble them — 32 hrs @ 110, +18%, split by 4 — and the total updates as you type. Free, no signup, and nothing you type ever leaves your browser.

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What people work out here

Sum & Carry is a plain-text calculator for the sums that are too small for a spreadsheet and too fiddly for a phone calculator — the ones where you need to see your working, label each line, and change a number without starting again.

Splitting costs

A restaurant bill with the tip on top, a month of shared house bills, or a weekend away where four people paid for different things. Add the lines, add a percentage, then write split by 4 to see the per-person share.

Quoting work

Hours at a rate, a rush fee as a percentage, minus the deposit already paid. Write design work 32 hrs @ 110 and the multiplication happens for you, so the client sees the same working you did.

Budgeting

Money in as positive lines, money out as negative ones, and the total at the bottom is what's left. Change one figure and everything below it re-reads instantly.

Property numbers

Monthly rental cash flow, a fix-and-flip margin, or a debt service coverage ratio. Name a line with a colon and reuse it further down — dscr: noi / annual debt service

The whole syntax, in one table

There is nothing to learn beyond this. Any line without a number becomes a heading, so you can write notes and section titles in among your figures.

You typeWhat happens
rent 1200Adds 1,200 to the total, labelled “rent”
deposit -2000Subtracts 2,000
32 hrs @ 110Multiplies a quantity by a rate
tip +18%Adds 18% of the running total above it
vacancy -5%Takes 5% off the running total
15% of 4000A share of a figure you state yourself
split by 4Shows the running total divided four ways
budget 1.5kk and m expand to thousands and millions
noi: rent - costsNames a line so you can reuse it below
Phase twoAny line without numbers becomes a heading

Guides

Worked walkthroughs for the sums people bring here most often. Each one opens the scratchpad with the numbers already in it.

Common questions

Is Sum & Carry free?

Yes, completely, with no account and no usage limit. The site is paid for by the single advertisement on the page.

Do my numbers get sent anywhere?

No. The whole calculator runs inside your browser as plain JavaScript. There is no server to send anything to, so nothing you type is uploaded, logged or readable by anyone else. Your sheets are kept in your own browser's local storage and stay on your device.

How does the share link work if nothing is uploaded?

The sheet is encoded into the web address itself. Sending the link sends the working, because the numbers travel inside the URL rather than through a database. That does mean a very long sheet makes a very long link.

What does the “=” symbol mean in the results?

It marks a worked-out figure — a named line, a split, or a ratio. Those are shown for reference and are deliberately never added into the total, so a subtotal can't be counted twice.

Can I use it for invoices or quotes I send to clients?

Yes. Export will copy the sheet as a plain-text email summary or a Markdown table, or print it to PDF with the totals laid out. It is a scratchpad rather than accounting software, so check anything that matters before you send it.

Does it work offline?

Once the page has loaded, yes — the calculator itself needs no connection. Your saved sheets are already on your device.

Can I change the currency?

Yes, with the selector above the results. It guesses from your browser's region the first time and then remembers your choice. The symbol is display only, so you can also switch it off entirely and work in plain numbers.