Quote to Cash · step 9 of 11
Raising the invoice
Converting a completed delivery into a demand for payment that the customer's systems can match and approve without a human having to intervene.
Also called: Billing · Sales invoicing · Revenue recognition trigger
- Owned by
- Credit Controller
- Also involved
- Despatch Coordinator, Inside Sales / Sales Coordinator
- Documents
- Sales Invoice, Credit Note, Packing Slip / Delivery Note
- Measured by
- Days Sales Outstanding (DSO)
What it is
The invoice is the formal demand for payment. It is also, for most companies, the point at which revenue is recognised, tax becomes due, and the debt starts ageing. Everything the chain has done up to now is unpaid work until this document is correct and accepted.
The word that matters is accepted. Raising an invoice is trivial; getting it through the customer's accounts payable process is the actual job. In any customer large enough to have a shared service centre, the invoice is matched automatically against their purchase order and their goods receipt, and if all three do not agree it is set aside — silently, and usually without anyone telling you.
So invoicing is less a finance task than a data task. The question is not 'is this invoice right?' but 'will this invoice match what the customer's system already believes?'
Why companies do it
Delivering goods creates a claim; the invoice is how that claim is asserted, evidenced and dated. It is also a legal document for tax purposes in most jurisdictions, with prescribed content. And it starts the payment clock — which is why the gap between despatch and invoice is pure lost cash, and why a two-day billing lag on a business turning over £20m costs roughly the same as giving every customer two extra days of free credit.
Inputs and outputs
What has to be there first
- The despatch record with actual quantity shipped — Despatch and shipment
- Proof of delivery — Despatch and shipment
Not required to raise the invoice, but required to defend it.
- The sales order: price, terms, references — Order entry
- The customer's purchase order number — Purchase Order (PO)
- Customer billing details, tax status and e-invoicing route — Finance master data
- Any agreed concessions or credits — Negotiation and revised offers
What it produces
- The invoice, issued to the customer — Sales Invoice
- An open receivable with a due date — Accounts receivable and collection
- Recognised revenue and tax liability — Finance
- A credit note where something was wrong — Credit Note
How it is done
01Invoice from the despatch, not from the order
The quantity on the invoice must be the quantity that physically left. This single rule prevents the most common matching failure there is, and it means an order that shipped in three parts produces three invoices, not one.
02Carry every reference the customer will match on
Their purchase order number, their part numbers, your delivery note number and date, the order line if their system uses line-level matching. These are not decoration — they are the join keys in someone else's database.
03Apply the correct price and the agreed terms
Price from the order as accepted, payment terms from the agreement, and any concession that was negotiated. An invoice at list price when a discount was agreed will be short-paid, and reconciling a short payment costs more than the discount did.
04Get the tax treatment right
Rate, registration numbers, place of supply, reverse charge, export evidence. Tax rules are jurisdictional and unforgiving, and an invoice with a tax defect can be rejected outright and has to be reissued — restarting the payment clock from the new date.
05Send it the way the customer can receive it
Post, PDF to a named inbox, EDI, or upload to their portal. Sending a PDF to the buyer who placed the order, when invoices must go to a shared service centre, is a common way to lose a month. Confirm the route once per customer and record it.
06Invoice the day the goods go
Every day between despatch and invoice is a day of free credit given away, and it is the easiest cash improvement available to most businesses because it requires no conversation with anyone.
07Attach or hold the supporting evidence
Delivery note, certification, timesheet, signed acceptance — whatever the customer's process demands. Some portals require the POD uploaded with the invoice; where they do not, keep it filed against the invoice for the query that arrives later.
08Credit and reissue properly when it is wrong
Do not amend an issued invoice. Raise a credit note referencing it, then issue a corrected invoice. Both documents need to exist for the customer's records, your tax records and the audit trail to agree.
What needs approval
Approvals only work when they happen before the commitment. Retrospective approval is a manager being told what has already been promised.
| Trigger | Approver |
|---|---|
| Credit note above a set valueCredit notes are where revenue quietly leaves; they need the same scrutiny as a discount. | Finance manager |
| Invoice raised before deliveryAdvance and milestone billing are legitimate but must be contractually agreed, not assumed. | Finance |
| Payment terms differing from the customer master | Credit control |
| Manual invoice raised outside the order flowThe highest-risk category — no order, no despatch, nothing to match against. | Finance manager |
Two identical invoices, sixty days apart
A worked example with real numbers.
Two suppliers deliver to the same customer on the same day, each for £7,354. Both parts were accepted without complaint. One is paid on day 30; the other on day 91.
Supplier A invoices on the day of despatch, from the despatch record: 388 units at £18.95, the customer's purchase order number 4500-887-2261, their part number, the delivery note number and date. It goes to the accounts payable inbox recorded in their customer master. The customer's system matches purchase order, goods receipt and invoice automatically, and it is approved without a human seeing it. Paid on day 30.
Supplier B invoices four days later during the weekly billing run, from the sales order: 400 units, because that is what the order said. The purchase order number carries a transposition from order entry. It is emailed to the buyer, who forwards it to accounts payable eleven days later.
The match fails twice — wrong quantity and unrecognised PO — and it lands in an exceptions queue. It is found on day 68 when credit control chases. The invoice is credited and reissued for 388 on day 71, with terms running from that date. Paid on day 91.
The work was identical. The difference was four fields and one send route.
| Cause | Days added |
|---|---|
| Weekly billing run instead of daily | 4 |
| Sent to buyer rather than accounts payable | 11 |
| Quantity mismatch — invoiced 400, received 388 | — |
| Transposed purchase order number | — |
| Sat unnoticed in exceptions queue until chased | 53 |
| Credit and reissue restarted 30-day terms | 23 |
| Total delay against Supplier A | 61 |
The point
None of the 61 days involved a customer refusing to pay or disputing the goods. Every one of them was created inside the supplier, and every one was created before the invoice was sent.
Common mistakes
MistakeMissing or wrong purchase order number
Why it happens: It was mistyped at order entry, or the customer issued a new PO and nobody updated the sales order. The invoice arrives and matches nothing.
What to do instead: Make it a mandatory field, print it on the acknowledgement so the customer can correct it early, and check it against the current PO before the invoice goes out.
MistakeInvoicing before the goods arrive
Why it happens: Month end is approaching and the revenue is wanted in this period. The invoice reaches the customer before their goods receipt exists, so the match fails and the invoice is rejected rather than held.
What to do instead: Invoice on despatch, and resist the month-end pull. Revenue recognised on an invoice that gets rejected is revenue you will reverse next month anyway.
MistakeSending the invoice to the person who placed the order
Why it happens: That is the contact everyone knows. In large organisations they have no role in payment and will forward it, eventually, or not.
What to do instead: Record the invoicing route as customer master data, separately from the buyer. Confirm it at account opening and again after any reorganisation on their side.
MistakeAmending an invoice instead of crediting it
Why it happens: It is faster and the customer has not paid yet anyway. Now two versions of one invoice number exist, tax records disagree, and both parties' audit trails are broken.
What to do instead: Credit in full, reissue with a new number. It takes a minute longer and is the only version that survives an audit or a dispute.
MistakeBatching invoices weekly
Why it happens: It is administratively tidy. It also means the average invoice is issued three and a half days after despatch, on every invoice, forever.
What to do instead: Invoice daily, or on despatch automatically. On a business invoicing £20m a year, removing a three-day lag frees roughly £165,000 of cash permanently.
MistakeNo proof of delivery when the query comes
Why it happens: The invoice was raised from the order, the POD was never filed against it, and the query arrives 70 days later when the driver's paperwork is gone.
What to do instead: File the POD with the invoice at the moment of issue. The cost is seconds; the alternative is crediting an invoice you were entitled to be paid.
Where the work happens
- ERP or accounting system
- E-invoicing networks and customer portals
- EDI
- Document storage for PODs and certificates
Terminology
- Three-way match
- The customer's automated check that purchase order, goods receipt and invoice all agree. Failing it is the usual reason a correct invoice is not paid.
- Payment terms
- When payment is due — 30 days net, 60 days end of month, and so on. End-of-month terms are materially longer than they look.
- Credit note
- A document reducing or cancelling an issued invoice. The correct mechanism for fixing an invoice that has already gone out.
- Self-billing
- An arrangement where the customer raises the invoice on your behalf from their goods receipt. Removes matching failures and removes your control.
- Milestone billing
- Invoicing against agreed stages rather than delivery, common on long projects and capital equipment.
- Retention
- A percentage withheld from each invoice until an agreed date or event, typically released long after the work is complete.
- Aged debt
- Outstanding invoices grouped by how overdue they are. The starting point of every collection conversation.
Common questions
›What has to appear on an invoice?
Legally, the requirements are jurisdictional and usually include your identity and tax registration, the customer's details, a unique sequential number, the date, a description of what was supplied, the amounts and the tax. Commercially, you also need the customer's purchase order number, their part references and the delivery note number — because those are what their system matches on, and an invoice that is legally perfect but unmatchable still does not get paid.
›When should an invoice be raised?
On despatch, for goods sold on delivery terms. Earlier only where the contract genuinely provides for advance or milestone billing. Later is simply lost cash — the payment terms do not start until the invoice is issued.
›Why do correct invoices go unpaid?
Almost always a matching failure rather than a dispute: a purchase order number that does not exist in their system, a quantity that disagrees with their goods receipt, a price that differs from their approved order, or delivery to a site that was booked against a different order. The invoice sits in an exceptions queue, and in most organisations nobody is responsible for telling the supplier.
›Can you change an invoice after issuing it?
No — you credit it and reissue. Amending an issued invoice breaks the sequence, breaks the tax record and leaves two documents with the same number in circulation. It is one of the few genuinely hard rules in the chain.
›What is self-billing and should you agree to it?
The customer raises the invoice themselves from their goods receipt and pays it. It eliminates matching failures completely, which is a real benefit. It also means the amount is calculated from their records, so any error in their receipt quantity or their price becomes your problem to detect. It works well where the pricing is simple and the volume is high.
›How much does slow invoicing actually cost?
It is arithmetic: annual revenue ÷ 365 × days of delay is the cash permanently tied up. A business turning over £20m that invoices three days after despatch has roughly £164,000 sitting in that gap, every day of the year. Unlike almost every other cash improvement, closing it requires no negotiation with anyone.
Tools for this
Downloadable, self-contained, and yours to keep — they run in a browser with no account and no data leaving your machine.
- Invoice GeneratorFreeCreate professional invoices for any country: 40+ currencies, VAT / GST / HST / sales-tax handling, tax-inclusive or tax-exclusive pricing, per-line discounts, and a built-in invoice register with paid / outstanding charts. Runs entirely in your browser. No installation, no account, no upload.
- Accounts Receivable AgingFreeAge your unpaid invoices into buckets, see what is overdue and by how far, work out days sales outstanding, and print a chase list for whoever is collecting. Runs in your browser. Nothing is uploaded.
Reviewed 2026-08-15. Nothing here is legal, tax or accounting advice — contractual and tax practice varies by jurisdiction.