Build a free invoice generator in Google Sheets with Claude and Apps Script

This post shows you how to get a free invoice generator in Google Sheets without writing any code yourself. You paste one prompt into Claude, answer its questions about your business, and it writes an Apps Script that turns a blank sheet into an invoicing tool: a form for each invoice, a dropdown of your services, PDFs filed in Google Drive and a log of every invoice you make.

I built this for a client who wanted very simple invoicing, with everything tracked in one Google Sheet and no subscription to Xero or QuickBooks. The demo in the video uses a car detailing business. Below are the steps, what you need, and where a sheet like this stops being enough.

What the invoice sheet does

Once the setup has run, your sheet has an invoice page and a new menu. This is what the version in my video does:

• Client details at the top: name, company, email, phone and address.
• A dropdown of your services on each line. Pick one, set the quantity, and the rate fills in from your price list.
• Line totals and an invoice total worked out for you, plus a notes box at the bottom.
• An Invoice tools menu with four options: set up the template again, preview the invoice, save it as a PDF, or start a new invoice.
• A preview showing your business name, the invoice number, the due date, who it's billed to, the line items and your notes.
• PDFs saved automatically into a Google Drive folder named after your business.
• An invoice log holding each invoice number, invoice date, client, total, a link to the PDF and when it was created.

What you need before you start

• A Google account. Google Sheets and Apps Script (the code editor built into Sheets) cost nothing.
• A Claude account, to write the script.
• The invoice generator prompt, which is free. It's a Google Doc anyone with the link can open.
• Your business details: the business name, the services you sell, a price for each, your currency and your tax setting.

Once it's built, running it costs nothing, because the script lives inside your own Google Sheet and runs under your Google account. Claude is only there to write the code at the start.

How to build the free invoice generator in Google Sheets

Give Claude your business details

Open the prompt, fill in your business details at the top, and paste the whole thing into Claude (this starts at 0:30 in the video). If you leave something out, Claude asks for it. It works through the business name, the services, a price for each one, the currency and the tax.

For the demo I gave the car detailing business three services: a wash at $20, a ceramic coat at $50 and a full detail at $100. I set the currency to USD and tax to none, only to keep the demonstration simple.

Claude then writes the full Apps Script. In my recording it took about three to four minutes. Under the code it adds a few next steps on setting it up, and they're worth reading if you get stuck later.

Paste the code into Apps Script

This is the part at 1:28 in the video, and it's all copy and paste:

1. 1Copy all of the code Claude wrote.
2. 2Open a new, blank Google Sheet. It doesn't need a name.
3. 3Go to Extensions, then Apps Script, and the script editor opens.
4. 4Select the placeholder code already in the editor (Ctrl+A on Windows, Cmd+A on a Mac) and delete it, so the editor is empty.
5. 5Paste in Claude's code and press Save.

Run the setup and allow permissions

Beside the Run button there's a dropdown listing the script's functions (2:00 in the video). Choose the setup one (in my version it was the function that sets up the invoice template), then press Run.

Google asks you to review permissions before the script can touch anything, since it builds pages in your sheet and saves files to your Drive. Sign in with the same Google account that owns the sheet.

The setup then builds the pages and the custom menu the invoicing needs. I said in the video to expect a couple of minutes. When it's done, a setup complete box appears back in the sheet. Press OK and the invoice page is ready.

Making your first invoice

1. 1Fill in the client's details: name, company, email, phone and address.
2. 2On each line, pick a service from the dropdown and type the quantity. The rate and line total fill in, and the invoice total updates.
3. 3Add any notes at the bottom.
4. 4If you can't see the Invoice tools menu, refresh the page. I had to refresh before it showed up.
5. 5Choose Invoice tools, then preview the invoice, and read every line before it goes anywhere.
6. 6Choose save as PDF. The file goes into your business's invoices folder in Google Drive, and the invoice log gets a row with a link to it.

For my test (from 2:56 in the video) I typed in a made-up client with a London address. The preview pulled through the business name, invoice number, due date, the billed-to details, the line items and the note, laid out as a finished invoice. The Drive folder and the invoice log follow at 3:44.

The log is what makes this more useful than a template you copy by hand. Every invoice number, date, client and total sits in one tab, each with a link to its PDF. Finding last month's invoice for a client means filtering one list instead of opening files one by one.

Where this invoice sheet falls short

This makes and files invoices. That's the whole job, so be clear about what sits outside it before you cancel any software.

• No bank feeds and no tax return. It won't pull in your bank transactions or prepare your taxes. If you need either, you still want accounting software such as Xero or QuickBooks.
• Check the tax yourself. I set tax to none for the demo, so the video never shows a tax line. If you charge VAT or sales tax, give Claude your rate in the prompt and check the totals on a test invoice before you send a real one.
• Sending is still manual. The version in the video saves a PDF to Drive. It doesn't email it, so you attach it and send it yourself.
• The log doesn't track payment. Its columns are the invoice number, date, client, total, PDF link and created time. Nothing there says whether an invoice has been paid, so chasing late payers is still on you.
• Your version won't match mine exactly. Claude writes the script fresh each time, so menu names, layout and the setup function's name can differ from the video.
• Prices come from a fixed list. Each line takes its rate from the services you gave Claude, which suits set prices like a wash or a full detail. If you quote a different price for every job, test how your version handles a one-off rate first.

My rule of thumb: if the main thing you'd pay accounting software for is producing invoices, this sheet covers it. Once you need bank feeds or help with your tax return, that's the point to move to proper accounting software.

Taking it further

The obvious next step is sending. Apps Script can run more automation, so you can add a button that emails the invoice you've picked straight to that client. I mention it at 4:14 but didn't build it in the video. The route is the same: ask Claude for the extra function and add it to the same Apps Script project.

For bigger versions of the same idea, see how a crane hire firm's billing time dropped by 15 hours a week, or how a property firm runs agreements and invoice chasing from one pipeline move.

If you'd like invoicing like this built for your business and connected to the tools you already use, book a free call and I'll go through what you need.