The layout is the easy part of proforma invoice in excel. What makes a document a valid tax invoice is its content and its numbering, and that is where almost every free template falls down. This page covers both, and then offers you a way to stop maintaining the file at all.
A format is a layout. An invoice is a record.
A template gets the first bill out of the door, and for a business issuing two or three a month that is a perfectly reasonable answer. Nobody needs software to send three invoices.
What a file cannot do is remember. It will not stop you reusing a number, it will not notice that a customer was billed twice, and it will not tell you in April what was still unpaid in February. Every one of those is a matter of record-keeping rather than of layout.
So the useful way to read this page is: get the content right first, because that is a legal question, and only then decide whether a file or a system should hold it.
A proforma is not an invoice, and that is the point
A proforma is a quoted offer laid out like an invoice: this is what it will cost, these are the taxes that will apply, this is what you are agreeing to. It is sent before the supply, usually to get an approval or an advance released.
Because it is not a tax invoice, it must not be numbered in your tax invoice series and it does not create a tax liability. Nobody can claim input credit against it. Label it clearly as a proforma or a quotation so there is no chance of it being filed as the real thing — a document headed "Invoice" that was meant as an estimate is how a number gets claimed twice.
The useful discipline is to keep proformas in their own series — PI/25-26/001 and so on — and to raise the real tax invoice when the supply actually happens, carrying the same lines across so the figures cannot drift.
Spelling varies in searches — proforma, pro forma, and "performance invoice" for the same thing — but the document is the same, and so is the rule about keeping it out of the invoice series.
Doing this in Excel: what works and what will bite
Excel is genuinely good at this up to a point. The arithmetic is reliable, the layout is yours, and everyone already has it. If that is where you are starting, a few habits make the difference between a spreadsheet that lasts a year and one that goes wrong in a month.
Keep the data and the document apart: one sheet of invoice rows that you never format, one sheet that renders a chosen invoice for printing. Hold customers and items on their own sheets and pull them in by lookup rather than retyping, because a customer whose GSTIN is typed forty times is a customer whose GSTIN is wrong somewhere. Lock every formula cell and leave only the inputs open. Never let two people hold two copies.
What Excel cannot do, however carefully it is built, is guarantee a number. There is no mechanism that stops a cell being overtyped, no record of who changed what, and nothing that enforces the next number in the series. That is not a formula problem; a spreadsheet simply has no authoritative state.
So the honest reading is: build it properly, use it while it suits you, and treat the day two people need it at once as the day to move.
What you get here instead of a file
- Every mandatory field present, because the document is built from records rather than typed into a layout.
- One numbering series, issued centrally, consecutive, restarting each financial year — so a number cannot be used twice.
- Customers stored once with GSTIN, address and state, so the details are right on the fortieth invoice too.
- Items stored once with HSN or SAC, rate and tax.
- The tax derived, not chosen — CGST and SGST or IGST, from the place of supply against your registration state.
- A clean PDF to print, email or send on WhatsApp.
- An answer to "what is unpaid", which no template has ever been able to give.
- Your data exportable to CSV, Excel and JSON at any time, on every plan including the free one.
- Free — ₹0, no card, no expiry.
From a template to a proper invoice in about five minutes
- Start free now — an email address and a password, no card.
- Enter your business name, address and GSTIN once. These are the fields you have been retyping.
- Add a customer with their GSTIN and state, or import your whole list from the spreadsheet you already have.
- Add the items you sell with their HSN or SAC codes and rates.
- Set the invoice number your series should carry on from, so there is no gap and no restart.
- Raise the invoice. The number, the tax split and the totals are already filled in.
- Download the PDF, or send it straight to the customer.
The numbering rule, which is where templates fail first
The invoice number has to be a consecutive serial, unique within the financial year, not more than sixteen characters, and made only of letters, numbers, hyphens and slashes. One series, or clearly separated series if you genuinely need more than one — but each consecutive in itself.
A file cannot enforce any of that. The number is typed, which means it can be repeated, skipped or quietly rolled back when yesterday's invoice is edited into today's. A duplicate is not found at billing time; it is found at return time, in the month after the one it happened in.
The other half of the rule is that a cancelled invoice keeps its number. Deleting the row and reusing the number leaves a gap in your books and a figure in your customer's, and reconciling that is a long afternoon.
This is the single most practical argument for a system over a file, and it has nothing to do with features.
What goes wrong between the file and the return
The return is where billing errors become visible, and they arrive in a predictable order.
Place of supply recorded wrong, so a supply is reported in the wrong state and the tax head is wrong. A missing customer GSTIN, which silently moves a B2B supply into the B2C summary where it cannot be claimed. HSN codes left blank on some lines, so the summary table cannot be built. A combined tax figure that has to be unpicked line by line. And duplicated or missing invoice numbers, which is the one that takes longest to resolve.
None of these is hard to avoid at the moment of billing. All of them are expensive to fix a month later, because by then the customer has their copy and may have filed against it.
That asymmetry — cheap to prevent, costly to correct — is the real case for capturing an invoice properly the first time.
Credit notes, debit notes, and fixing a wrong invoice
An issued tax invoice is not something to edit. If the value was too high, or goods came back, the correction is a credit note that references the original invoice. If it was too low, a debit note. Both carry their own numbers and both appear in your return.
There is a deadline on the credit note that matters: the adjustment has to be declared by the return for the relevant month of the following financial year, or by the annual return, whichever comes first. Past that, the note exists commercially but the tax cannot be adjusted.
Software that lets you quietly retype an invoice raised last month is not doing you a favour.
Reverse charge, exports and the supplies that behave differently
Not every supply is a straightforward taxable sale. Some notified supplies put the tax liability on the recipient rather than the supplier. Exports and supplies to an SEZ can be made under a bond or LUT without payment of tax, or with tax and a refund claimed afterwards. Composition dealers cannot charge tax at all and must say so on the bill.
Each of these changes what the invoice has to say — the reverse charge marking, the LUT reference, the "composition taxable person" declaration. They are not exotic cases; most businesses hit at least one.
The fields are on the invoice in Billixo whether or not you use them, so the day you need one you are not looking for a workaround.
The AI, and what it is actually for
The useful application of AI to billing is not a chatbot. It is the twenty minutes a day spent retyping things that already exist on paper.
- Scan a supplier bill. Photograph it; the lines, the GSTIN, the tax and the totals come back as a draft you check rather than a form you fill.
- Find the HSN code. Describe the product in plain words and get a code to confirm, instead of scrolling a list of eleven thousand.
- Ask about your own numbers. "What is outstanding over sixty days?" answered from your data, not a manual.
- Write the reminder. A polite, specific chase for an overdue invoice, ready to send on WhatsApp.
Nothing is sent anywhere until you ask for it, and the platform runs on whichever model it has been configured with — including one hosted on your own server.
Where this fits in a working day
Morning: yesterday’s supplier bills get photographed and become purchase records. Through the day: invoices go out as goods do, shared on WhatsApp before the customer has left. End of the week: the receivables list says who to call. End of the month: the GST summary is a download, not a project.
None of that requires a new habit, which is the point. A billing system that needs discipline to work is one that stops working the first busy week.
The price, plainly
Free is ₹0 and stays ₹0. The paid plans are bought for a fixed term, paid once, with no auto-renewal and no card kept on file — when a term ends the account drops back to Free until you decide to buy again.
There is no per-invoice charge, no per-user surprise on the free plan, and no feature that is technically included but practically throttled. What the plan says you get is what you get.
Compare the plans on the home page, or just start free now and look at the ceiling from the inside.
Where your data lives
On the server this platform is installed on. Every record carries a company identifier and every query is scoped to the signed-in account at the framework level, so one business cannot read another’s data by any route, including a crafted one.
Sign-in is rate limited, sessions can be restricted to one device per user, and passwords are stored hashed. Exports are available on every plan, free included: if you ever want to leave, your data leaves with you.
Frequently asked questions
Will my existing invoice numbers carry on?
Yes. You set the number the series should continue from when you start, so there is no gap and no restart in the middle of a financial year. That is usually the first thing to get right when moving off a file.
Can I get my data back out?
Yes, on every plan including the free one — CSV, Excel and JSON. Records you cannot export are not records you own, so this is not a paid feature.
Is a template invoice legally valid?
A document is valid if it carries the content the law requires, whatever produced it — a printed book, a spreadsheet or a system. The format is not the issue; the missing fields are. Most free templates are short of place of supply, an HSN or SAC per line, or the tax heads shown separately, and any one of those makes the document deficient.
Can more than one person use it?
On the paid plans, yes — team logins with their own credentials. The Free plan is a single login, which suits a one-person operation and is usually the first limit a growing business hits.
Is my data shared with anyone?
No. It sits in this installation, scoped to your company. AI requests only happen when you explicitly ask for one, and nothing is sent anywhere otherwise.
See it working on your own bills
The fastest way to judge billing software is to bill with it. Photograph one supplier invoice, raise one sales invoice, and look at the PDF your customer would receive.
Open the software demo → — free account, no card, about a minute to set up.
More details on the home page → — what it does, what it costs, and where the limits are.
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