Blog · Choosing software

Why purchase orders in email and spreadsheets break

Published 8 October 2026 · 6 min read

A purchase order template, a spreadsheet with a numbering column and approvals in email threads will carry a small team a long way. It breaks in predictable places: duplicate numbers, orders edited after they were sent, approvals that leave with the person, and nobody able to say what has been committed this month. It starts to hurt once more than one person raises orders or approves them. Keep your supplier list and your limits; move the numbering, the approvals and the record of each order into a system.

The setup small teams start with

It usually looks like this. There is a purchase order (PO) template: a document with the company’s name at the top, a few lines for items and a total. There is a spreadsheet, often called the PO log, with columns for the number, the date, the supplier, the amount and who asked. And there is email. Someone writes “can I order this?”, a manager replies “yes, go ahead”, and the requester fills in the template, takes the next number from the log and sends the PDF to the supplier.

Nothing about this is wrong. It costs nothing, everyone understands it, and when one person does all the buying it is as reliable as that person. The trouble is that each step depends on someone remembering the next one, and the steps aren’t connected. The number in the log, the approval in an inbox and the PDF the supplier received are three separate records, and nobody checks them against each other.

Where it fails

The failures are rarely dramatic. They show up as a question nobody can answer quickly, or a supplier invoice that doesn’t match anything.

• Two people take the same number. Both open the log, both see that the last order was 0412, and both send 0413. The supplier now has two different orders with one number, and an invoice quoting it could belong to either.
• The template is edited after it was sent. Someone opens last week’s order to reuse it, changes the quantity and saves over the file. The copy on the shared drive no longer matches what the supplier has, and nobody can tell which version was approved.
• The approval lives in an inbox. The “yes” is a reply in one manager’s mailbox. When that manager leaves, or the auditor asks who signed off a large order, the evidence goes with the mailbox, or takes an afternoon to find.
• Nobody can say what has been committed this month. The log has amounts, but only if everyone filled them in, in the same currency and consistently with or without tax. Orders sent but not yet invoiced are invisible to anyone looking at the accounts.
• The same quote gets ordered twice. A quote is forwarded to two people, or a requester resends because they didn’t hear back. Nothing records that the quote was already ordered, so both orders go out, and the second turns up as a delivery nobody expected.
• The supplier invoices a name that isn’t the buying entity. A group with two companies, or a trading name and a legal name, uses one template. The supplier invoices whatever name is on the order, the invoice reaches a company that didn’t buy anything, and someone has to ask for it to be reissued.

Failure, cause and fix

Each failure has a plain cause, and the fix is usually to take one step out of people’s hands.

When it starts to hurt

The setup holds while one person raises orders and one person approves them. It starts to strain at the first of these:

• A second person starts raising orders, so two people can reach for the same number.
• Who approves depends on the amount, so the requester has to work out who to ask.
• There is a second site or a second company, so the template and the log need to know which one is buying.
• The month-end question “what have we ordered that hasn’t been invoiced?” takes more than a few minutes to answer.
• Someone who approved orders leaves, and their mailbox goes with them.

Volume matters less than hand-offs

People expect the setup to fail when orders pile up. It tends to fail earlier, when orders pass between people. A team sending a few orders a week with three requesters and two approvers will run into more of the problems above than one person sending fifty, because the failures come from hand-offs, not from typing.

So the useful test isn’t how many orders you send. It is how many people touch an order between “we need this” and the supplier receiving it, and how many places the record of that journey is kept.

What to keep from the spreadsheet

The spreadsheet usually holds three things worth keeping, and they are the slowest part of any change to rebuild.

• Your supplier list. Names, legal names, the email address orders go to, VAT numbers and payment terms. Clean it before you move it: merge duplicates, mark the suppliers you actually use, and drop the ones you haven’t bought from in a year.
• Your limits. Who can spend how much without asking, and who approves above that. If this lives in people’s heads, write it down now; it is the rule a system will enforce. How to set approval limits walks through it.
• Your last PO number. Note it, so the new sequence doesn’t overlap the old one. How to number purchase orders covers formats.

What needs a system

Keep the old log, read-only, as the record of past orders, and finish the open orders there. You don’t need to import years of history to start; you need the suppliers, the items you buy often and the people who approve. How to move purchase orders out of a spreadsheet covers the move step by step.

You don’t need a large procurement system to fix the failures above. You need something that does a short list of things every time, without anyone remembering to. At minimum, a replacement should:

• Issue the PO number itself, once, when the order is created.
• Route each request by its amount, so the requester doesn’t pick their own approver, and stop anyone approving their own request.
• Record each approval against the request: who, when and at what amount.
• Keep the quote and supporting documents on the request, so the approver sees what they are agreeing to.
• Lock an issued order. A change is a revision with a history, not an edit to a file.
• Print the right buying entity’s legal name and address on each order.
• Show every order in one list with its status, so committed spend is a filter, not a project.

Anything beyond that is optional

Goods receipt, invoice matching and budgets are useful to teams that will use them every day. For many small teams they add steps that nobody keeps up, and the team drifts back to email. Start with the list above, and add more only when a real problem asks for it. How to choose purchase order software goes through those choices.

Questions

Can we keep using a spreadsheet for purchase orders?

Yes, while one person raises and sends orders and approvals are simple. Give the numbering to one person, keep approvals in one shared place rather than personal inboxes, and save every sent PO as a PDF that nobody edits. Once more people are involved, those rules get harder to keep.

Is an email approval good enough for audit?

An email shows that someone agreed, but it is hard to find, lost when a mailbox is closed, and doesn’t show which version of the order was approved. Auditors generally want the approval tied to the specific order and amount. Check with your auditor what they expect.

How do we stop duplicate purchase order numbers?

Have one source issue the numbers: a single person, or a system that assigns the number when the order is created. Never let people type the next number themselves.

When should a small business move purchase orders off spreadsheets?

When more than one person raises orders, when approvals depend on the amount, or when you buy for more than one company or site. Any one of those is usually enough to make the hand-offs fail.