Purchase order approval process: how to route, escalate and record every PO

In the three-site example below, a $12,000 equipment purchase takes 3 working days to approve if it climbs every level in turn, 1 day if the deciding approver and the capex review sign at the same time, and 8 days on the every-level route if the VP of Operations is on leave for a week and nobody covers.

The limits are the same each time. What changes is how the request moves between approvers.

What is a purchase order approval process?

A purchase order approval process is the set of rules that takes a purchase from request to approved order. It decides who sees the request, in what order, and what happens at each decision.

Many organisations approve at the requisition stage, before a buyer raises the PO. The difference between a purchase requisition and a purchase order matters here: the requisition asks permission, and the purchase order commits the money with a supplier. Some add a second check when the final price differs from the estimate.

The process sits on top of an approval matrix, which sets who can approve how much. This guide covers how a request moves through it. US federal internal control standards treat this as a core control. Only people acting within their authority should commit an organisation's money, and riskier transactions can need sign-off from more than one level (GAO Green Book, 2025, table 1).

How do you route a PO by amount, site and role?

Work out the route from the amount, the site, the requester's role and the category of spend. Then send it to the lowest role whose limit covers it, plus any specialist the category needs.

The example uses the Approval Matrix Builder's sample limits: Site Manager $2,500, Regional Ops Director $15,000, VP Operations $50,000, CFO $250,000. Three sites share one regional director. Hillcrest is the smallest, so its site manager's limit is $1,000. Category rules come from the same sample: off-catalogue buying and capital equipment approve at half the usual limits, and capital equipment can't be signed at a site.

The two $1,840 rows show why site matters: the same order stops at Northgate's manager but goes to the regional director from Hillcrest. The off-catalogue row shows category at work: Riverside's manager can sign $2,500 of contracted supplies but only $1,250 off catalogue, so $1,600 goes up a level.

The capital purchase skips two levels. Site managers can't approve capital spend, and the regional director's limit for it is $7,500. The VP's is $25,000, so the VP decides.

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Should approvals run in sequence or in parallel?

Run approvals in sequence when a later approver needs an earlier decision. Run them in parallel when each person checks something different. A VP and a capex reviewer look at different questions, so neither needs to wait for the other.

The time each route takes is a simple sum:

In sequence: elapsed time = t₁ + t₂ + … + tₙ

In parallel: elapsed time = the longest single t

Here t is how long each approver takes to decide. If an approver is away and nobody covers, their t includes every day they are out.

Take the $12,000 capital purchase from Riverside. Assume each approver decides within one working day.

Skipping levels that add nothing saves a day per level. A named delegate saves the whole absence.

What happens when an approver rejects a PO?

A rejected request goes back to the requester with a written reason, to fix and resubmit or to drop.

Treat "change this" and "no" as two outcomes. The first sends the request back for editing, for a wrong budget code, a missing quote or too many units. The second ends it. The reason stays on record in both cases, and the approval matrix guide explains what those reasons tell you over time.

Then decide where a resubmitted request goes. If the amount, category, site or supplier changed, run the route again from the start, because the earlier sign-offs were given on a different request. If only the paperwork changed, such as an attached quote, it can return to the person who rejected it.

Does a PO need re-approval if it changes after approval?

Yes, when the change could alter the decision. Set the triggers in advance so buyers don't judge each case:

• The total rises past a tolerance, such as 10%. Riverside's $1,600 off-catalogue order comes back from the supplier at $1,790. That is 12% more, so it goes back to the regional director.
• The new total crosses a limit. A Northgate order that grows from $2,400 to $2,600 is only 8% higher, but it now needs the regional director.
• The supplier, category or delivery site changes. Each can change the route or the risk.

A lower total or a later delivery date rarely needs a new decision. Either way, record the before and after values.

Who approves when the approver is away?

A named delegate approves for a set period, and the record shows whose authority they used. If no delegate is named, the request sits in an empty inbox until someone notices.

Four rules keep delegation safe:

1. Name the delegate in advance, usually a peer or the next level up.
2. Give it dates. Delegation ends when the approver returns.
3. Never delegate to the requester, or to anyone who would then approve their own purchase. Segregation of duties in purchasing explains the conflicts to avoid.
4. Keep the limit honest. If the delegate's own limit is lower than the request, either the delegation grants the higher limit in writing or the request goes up a level.

How long should PO approval take?

Set a response target for each level, such as one working day at a site and two for central roles, and escalate when it is missed.

A simple escalation rule: remind the approver when the target passes, then send the request to their delegate or the next level up at twice the target. Escalate upwards only. A higher approver can sign a smaller amount. A lower one can't sign a larger one.

Slow approval is expensive. In our cost per purchase order example, chasing and giving approval was the costliest single step: $13.00 of the $73.60 each PO cost. At the invoice end, our early-payment discount example collects $60,025 a year with two-day approvals and $13,705 with nine-day ones.

Can managers approve purchase orders on a phone?

They should be able to. Site and area managers spend most of the day away from a desk.

Mobile approval works when the approver sees everything on one screen: items, quantities, total, budget code, reason and route. Approving should take one tap, and rejecting should require a reason. Approval workflow software does this better than email, where a reply is hard to tie to one version of the request.

What should the approval record show?

It should let an auditor answer five questions without asking anyone: who approved, when, which version, under which rule, and on whose behalf. Record:

• The route worked out at submission, and the rule that produced it.
• Each decision, with the approver, the time and the amount they saw.
• Any delegate, and who they were covering.
• Every escalation, rejection reason and re-approval, with before and after values.

Keep the log append-only, so entries are added but never changed. A procurement audit trail built that way lets finance rebuild any purchase.

How to set up a PO approval process in seven steps

1. Start from your approval matrix. If you don't have one, build it first with the approval matrix guide.
2. List the routing inputs: amount, site, role and category. Note any site that needs different limits.
3. Route to the deciding level plus any specialist. Add a lower level only if it knows something the deciding approver doesn't.
4. Choose sequence or parallel for each route. Specialists usually go in parallel.
5. Write the rejection and re-approval rules, including the tolerance that triggers a new decision.
6. Name a delegate for every approver and set response targets with escalation.
7. Review monthly by site: time per level, rejection reasons and escalations. A level that always escalates needs a different approver or limit.

When this process doesn't apply

Four kinds of spending need a different route.

• Emergencies. A burst pipe at night needs a plumber now. Allow the purchase, then require approval within a working day.
• Call-offs against a standing order. The approval happens once, when the blanket purchase order is set up.
• Invoices with no PO, such as utilities. These follow an invoice approval workflow instead.
• Very small teams. With one buyer and one owner, a written limit and a monthly review may be enough.

For the bigger picture of buying across locations, see our guide to multi-site procurement.

Sources

• US Government Accountability Office, Standards for Internal Control in the Federal Government (GAO-25-107721), May 2025, table 1 under paragraph 10.04, "Authorization of transactions".