Article
Accounts Payable Outsourcing Services: Hire, Outsource, or Automate?
Accounts payable outsourcing services are third-party providers who take over invoice processing, approval routing, and bill payment for your business. You hand them invoices; they key them in, route them for approval, and pay them on your schedule - for a per-invoice fee or a flat monthly rate. It is one of three ways to get invoices processed: do it yourself (or hire someone to), outsource it to a service, or run it through software that does most of the keying and checking for you.
If you are the person who currently pays the bills - owner, office manager, bookkeeper - and you are weighing these three paths, the honest answer is that the right one depends almost entirely on how many invoices you process a month and how much of the work is judgment versus data entry. This guide walks through what each option actually costs, what it gets you, and the volume threshold where the math changes.
What do accounts payable outsourcing services actually include?
Most AP outsourcing providers offer some version of the same core scope: they receive your vendor invoices (by email or a shared inbox), enter the data into your accounting system, route the invoice for your approval, and - once approved - schedule or execute the payment. Some also handle vendor onboarding, W-9 collection, and 1099 prep. What they generally do NOT do is make judgment calls about whether an invoice is correct: a human on your side still has to catch a rate that does not match the contract or a bill for work that was never delivered, because the outsourcer is checking that the invoice looks complete, not that it is right.
What does it cost to process an invoice today, with no outsourcing?
Before comparing outsourcing to anything, it helps to know the baseline. APQC's cross-industry benchmarking, based on data from 5,846 organizations, puts the median cost to process a single accounts payable invoice at $6.00 - covering labor, overhead, and the time it takes from receipt to payment. That figure is for the process itself, independent of who or what is doing it; it is the number every outsourcing or software pitch is ultimately trying to beat.
A second number matters just as much and almost never gets mentioned in the "cost per invoice" conversation: APQC's benchmarking also finds that a median organization sees 1.5% of its annual disbursements go out as duplicate or erroneous payments. That is not a processing cost - it is money that actually left the bank account and should not have. Any honest comparison of hiring, outsourcing, or software has to account for both: the hours spent processing invoices, and the leakage that happens when nobody catches an error before it is paid.
What does it cost to hire someone to do AP in-house?
If you hire a dedicated accounts payable specialist, Robert Half's own published salary data puts typical base pay in the roughly $53,000 to $68,000 range depending on market, with most mid-size metro areas clustering around $55,000 to $61,000. That is base salary only - it does not include payroll taxes, benefits, equipment, or management time, all of which add meaningfully to the real cost of the role. It also assumes you can find and retain someone, and that the role has enough volume to justify a full-time hire.
What does accounts payable outsourcing cost, and what do you get for it?
Outsourcing providers typically price one of two ways: a per-invoice fee, which falls as volume rises, or a flat monthly retainer scaled to your invoice count. The appeal is that you are not managing an employee, you can usually scale the service up or down with volume, and a provider with a dedicated AP team may process invoices faster than a generalist doing it between other tasks. The tradeoff is that you are handing financial data to a third party, you still need someone on your side approving payments and catching the invoices that do not match the agreement, and most outsourcers price and staff for standard PO-based processing - not for subcontractor, SOW, or time-and-materials billing, which is common for services firms and requires reading the actual contract terms, not just matching a PO number.
What does AP software cost and change, compared with outsourcing?
AP software automates the data entry and approval routing that a human or an outsourcer would otherwise do by hand, and increasingly it also checks the invoice against the purchase order, the contract, or the rate card before it is approved - catching the kind of discrepancy a busy approver might miss. Software usually scales on a flat or per-seat/per-invoice subscription rather than a labor-based fee, which tends to make it cheaper than a human-labor model (hire or outsource) once volume is high enough to justify the setup. The work does not disappear - a person still reviews what the software flags and approves every payment - but the hours spent on manual entry and first-pass checking shrink substantially. One overview of what AP software actually checks walks through how 2-way, 3-way, and 4-way matching work and where each stops short of reading the full agreement.
Hire, outsource, or software: a side-by-side comparison
| In-house hire | Outsourced AP service | AP software | |
|---|---|---|---|
| Typical cost basis | Base salary roughly $53,000-$68,000 (Robert Half), plus payroll taxes, benefits, and management time | Per-invoice fee or flat monthly retainer, scales with volume | Flat or per-invoice subscription, scales with volume |
| Who still makes judgment calls | Your hire | You or your team, even after the provider processes the invoice | You or your team, with software flagging exceptions |
| Checks against the contract/rate card | Only if the person knows to | Rarely - most price for PO-based processing | Increasingly, in tools built for agreement-level matching |
| Data stays in-house | Yes | No - shared with a third party | Yes, inside your own accounting system |
| Best fit | Steady, moderate volume; want a dedicated owner of the process | Overflow or seasonal volume; no interest in managing headcount | Growing volume; want to absorb the work before adding headcount |
| Baseline cost per invoice to beat | $6.00 median, APQC | Varies by provider and volume | Varies by vendor and plan |
How many invoices a month changes the math?
Volume is the real variable. Below roughly 200 invoices a month, the fixed costs of any of these options - setup time, onboarding a vendor, implementing software, training a new hire - often outweigh the labor hours saved, and the honest answer may be that your current process, done carefully, is still the right one. Above that volume, the math usually tips toward outsourcing or software, because the per-invoice savings start to outweigh the fixed cost of switching. If you are below that line and still drowning in invoices, the problem is more likely a process issue (no clear approval chain, invoices arriving in six different inboxes) than a volume issue, and it is worth fixing that before paying for a solution to a different problem.
When does it make sense to absorb the work instead of hiring?
The calculation most owners actually run is not "what does this cost instead of a salary" - it is "what does this let me put off." If your invoice volume is approaching the point where the person currently paying bills (you, a bookkeeper, an office manager) is spending a day or more a week on it, software or an outsourced service can absorb that load before you need to add a dedicated AP hire. That is a different claim than replacing anyone: a person still reviews and approves every payment either way. The honest reason to make this move before hiring is the leakage, not just the hours - a firm processing a few hundred invoices a month at the 1.5% median duplicate/erroneous rate APQC reports is losing real money to errors nobody caught, on top of the time spent processing. The software or service that absorbs the work pays for itself twice: first in the hours back, then in the overbilling or duplicate payment it catches before it goes out the door.
For services firms paying subcontractors on an SOW or a rate card rather than a clean PO, that second point matters more than it does for a typical product company, because most of what gets missed - a rate that does not match the signed rate card, a line item outside the scope of work - never shows up as a duplicate payment. It shows up as an invoice that looks completely normal and gets approved anyway. A benchmark breakdown of what one invoice actually costs to process goes deeper into where that $6.00 median goes and how recovered overbilling changes the return on any of these options.
Frequently asked questions
Is accounts payable outsourcing cheaper than hiring an AP specialist?
It depends on volume. Outsourcing typically prices per invoice or as a flat retainer that scales with volume, while an in-house hire costs a fixed salary - roughly $53,000-$68,000 base - regardless of how many invoices arrive that month. At low volume, outsourcing or software is usually cheaper than a full-time hire; at high, steady volume, a dedicated hire can be more cost-effective per invoice.
Does an AP outsourcing provider check invoices against my contracts?
Most do not. Outsourcing providers are generally built around standard purchase-order-based processing: matching an invoice to a PO and sometimes a receipt. Checking an invoice against a signed SOW, contract, or rate card - which is where overbilling on subcontractor and time-and-materials work tends to hide - usually still falls to someone on your team unless you are using a tool built specifically for agreement-level matching.
What is the average cost to process one invoice?
APQC's cross-industry benchmarking, based on 5,846 organizations, puts the median cost at $6.00 per invoice, covering labor, overhead, and processing time from receipt to payment.
How many invoices a month justifies automating or outsourcing AP?
As a rough threshold, automation or outsourcing tends to pay off above roughly 200 invoices a month; below that, the fixed cost of switching often outweighs the labor hours saved, and a well-run manual process can still be the right call.
Will AP software or an outsourcing service replace my bookkeeper?
No - and that is by design. Every payment still needs a person to approve it; software and outsourcing services absorb the data entry, routing, and first-pass checking so the person who pays your bills is not doing it all by hand, not so that role disappears.
Do duplicate payments really add up to a meaningful amount of money?
Yes. APQC's Open Standards Benchmarking finds that a median organization sees 1.5% of its annual disbursements go out as duplicate or erroneous payments - money that was paid and should not have been, separate from the labor cost of processing the invoice in the first place.