Invoice Approval Routing: How to Route Invoices by Amount, Department and PO

The three things that decide where an invoice goes

Amount, cost center and PO status decide almost every routing rule; vendor, GL account and entity rules handle the exceptions.

Routing factors
Factor	What it decides	Example rule
Amount	The level of authority needed	Over $25,000 also needs the controller
Department or cost center	Whose budget the cost hits, so who approves	Marketing invoices go to the marketing budget owner
PO status	Whether the spend was already approved	Matched PO invoices within tolerance skip approval
Vendor	Special handling for sensitive vendors	Legal fees always go to the general counsel
GL account	Review of specific spend types	Capital expenditure accounts go to the controller
Entity or location	Who has authority in each company	UK entity invoices go to the UK finance lead

Most organizations already have a delegation of authority. The approval matrix is that policy applied to invoices, written precisely enough that a system or a new AP clerk can follow it without asking.

Example invoice approval matrix

This example uses four amount bands and routes by role, so the matrix survives people changing jobs.

Example approval matrix for non-PO invoices
Invoice amount	First approver	Second approver	Notes
Up to $2,500	Budget owner of the cost center	None	Recurring utilities can be pre-approved by contract
$2,500 to $10,000	Budget owner	Department head	Department head can delegate during absence
$10,000 to $50,000	Department head	Controller	Controller checks coding and budget
Over $50,000	Department head	CFO	Board policy may require more for capital items

Example thresholds for illustration. Set yours from your own delegation of authority and invoice volumes.

PO-backed invoices: approve once, at the PO

When an invoice matches its purchase order and receiving record within tolerance, the spend was already approved, so a second approval adds delay without adding control.

The approval happened when the PO was raised and approved. Three-way matching then confirms the invoice charges what was ordered, at the agreed price, for what was received. If all three agree within your tolerance, the invoice can go to payment. If they do not, it goes to an exception queue for the buyer or requester, not through the normal approval chain. See how three-way matching works.

How much this saves depends on your PO coverage. In Ardent Partners’ State of ePayables 2025, 65.4% of invoices were linked to a PO on average, rising to 84.0% for Best-in-Class AP teams against 47.3% for all others. The rest are non-PO invoices that need approval by a budget owner.

Non-PO invoices: route to the budget owner

A non-PO invoice has had no prior approval, so it goes to the owner of the budget it is charged to, with higher amounts escalating by band.

Code first, then route. The cost center and GL account decide the approver, so coding has to happen before routing.
Recurring contracts. Rent, software subscriptions and utilities can be approved once per contract, with invoices checked against the contract amount.
Unknown cost center. Send it to AP or the controller to code, not to a guessed approver.

Delegation, reminders and escalation

Every approver needs a delegate for absences, every invoice needs a time limit, and every rule set needs a fallback approver for invoices nothing else covers.

Keeping approvals moving
Control	How it works
Delegation	An approver names a delegate with at least the same authority, for a set date range.
Reminders	Automatic reminders after a set time, for example two business days.
Escalation	After a deadline, the invoice moves to the approver’s manager or the next authority level.
Fallback approver	Invoices no rule covers go to a named role, such as the controller, never to nobody.
Month-end priority	Invoices for the closing month are flagged so they are approved before cut-off.

Slow approvals are one of the main reasons invoices miss the cut-off. See the AP month-end close guide.

Segregation of duties and the audit trail

The person who requests a purchase should not approve its invoice, and the person who approves an invoice should not release the payment.

Requester, approver and payer are different people. Block self-approval in the system, not just in policy.
Vendor master changes are separate. Whoever approves invoices should not be able to change vendor bank details.
Record every decision. Who approved, when, at what amount and under which rule. Auditors test this trail.
Approve invoices and payments separately. Payment approval is its own control; see payment run approvals and controls.

To check your controls, take the AP audit readiness assessment.

Common approval routing mistakes

Most slow approval processes have too many approvers, approvals done by email, and no rule for the invoices that fit nowhere.

Too many approvers. Each extra approver adds days and weakens ownership.
Email approvals. Replies are hard to find, easy to forge and leave no reliable audit trail.
No fallback. Invoices without a matching rule sit in AP until someone notices.
Re-approving matched PO invoices. This doubles work on the invoices with the strongest controls.
Names instead of roles. Rules break when people change jobs.

How to design your approval matrix

Start from your delegation of authority, route by role, handle PO-backed invoices separately, and test the matrix against real invoices before you publish it.

1
Step 1
List your invoice types: PO-backed goods, PO-backed services, non-PO operating expenses, recurring contracts and one-off capital purchases.
2
Step 2
Set amount bands that match your delegation of authority, usually three or four bands rather than one per manager.
3
Step 3
Assign an approver role to each band and department or cost center, using roles (budget owner, department head, controller, CFO) instead of named people.
4
Step 4
Decide how PO-backed invoices that match within tolerance are handled: no further approval, or a single confirmation by the requester.
5
Step 5
Add rules for exceptions to the pattern: specific vendors, GL accounts, entities or projects that always need a particular approver.
6
Step 6
Define delegation for absences, reminders, an escalation path and a fallback approver for invoices no rule covers.
7
Step 7
Check segregation of duties, test the matrix against last month’s invoices, then publish it and review it at least once a year.

For more practical advice, read invoice approval workflow best practices and how to automate invoice approval workflows.

Approval routing in Aequo AP

Aequo AP routes invoices by rules on amount, department and vendor, sends reminders, flags invoices past their approval deadline and records every decision in an audit trail.

When no rule matches, Aequo AP suggests an approver based on who approved similar past invoices, and someone on your team chooses whether to assign it. It is never assigned automatically.

Frequently asked questions

How should invoice approvals be routed?

Route each invoice by three things: its amount, the department or cost center it is charged to, and whether it is backed by a purchase order. Amount sets the level of authority needed, the cost center sets whose budget it is, and a matched PO can reduce or remove approval because the spend was already approved when the PO was issued.

What is an invoice approval matrix?

An invoice approval matrix is a table that says who must approve an invoice based on its amount, department, invoice type and sometimes vendor or GL account. It is the written version of your delegation of authority for payables.

Do PO-backed invoices need approval?

Often not a second full approval. The spend was approved when the purchase order was issued, so an invoice that matches the PO and the receiving record within tolerance can go straight to payment, or need only a quick confirmation. Invoices that do not match go to an exception queue instead.

Who should approve non-PO invoices?

The budget owner for the cost center being charged, with higher amounts escalating to a department head, the controller or the CFO under your amount bands. Non-PO invoices have had no prior approval, so they always need at least one.

How many approvers should an invoice have?

As few as your controls allow, usually one or two. Every extra approver adds delay and makes each approver assume someone else checked the details. Add approvers for higher amounts and higher-risk spend, not as a default.

What happens when an approver is out of office?

A good routing setup lets approvers delegate to a named person for a set period, sends reminders when an invoice waits too long, and escalates to the next level of authority after a deadline. Delegation should never go to someone without the authority for that amount.

What is the difference between invoice approval and payment approval?

Invoice approval confirms the charge is valid and should be recorded as a liability. Payment approval confirms which approved bills are paid, when and from which account. They are separate controls and should usually be done by different people.

Automate matching, approvals and exception handling

Aequo AP captures invoices, matches them to purchase orders and receipts, routes approvals and flags duplicates and exceptions, then syncs with QuickBooks Online, Xero, FreshBooks or Zoho Books.

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Sources

Checked on October 22, 2026. Vendor capabilities and prices change; confirm current details with each vendor.

Ardent Partners, The State of ePayables 2025: AP's Unfinished Journey — Web-based survey of 204 AP professionals and their organizations. Source of the share of invoices linked to a PO.