Accounts payable cost per invoice calculator

By Nicolau Matarrodona, founder · Published 29 April 2026 · Updated 24 October 2026

The accounts payable cost per invoice is the annual cost of the process (team hours at their hourly cost, including the hours spent resolving exceptions) divided by the invoices of the year. With this calculator's starting assumptions (36,000 invoices a year, 12 minutes per invoice, 20% with an exception taking 45 extra minutes and EUR 30 an hour) the result is EUR 378,000 a year and EUR 10.50 per invoice. Replace each assumption with your own: the formula is in plain sight and the figures you type are neither sent nor stored.

Calculate with your assumptions

Supplier invoices per year

invoices

All companies in the group, with and without a purchase order.

Minutes of manual work per invoice

min

Open, record, check against the purchase order and delivery note, request approval and file an invoice with no issues.

Invoices with an exception

Price or quantity difference, missing delivery note, possible duplicate, wrong tax data.

Extra minutes per exception

min

Calls to purchasing and the warehouse, e-mails to the supplier, corrective invoices.

Team cost per hour (including social charges)

EUR/h

Employer cost, not gross salary.

Working hours per person per year

According to the collective agreement and working week.

Scenario: exception-free invoices that no longer need manual handling

You choose it. It is not a measured figure for any tool.

Hours per year in accounts payable12,600 h

Annual cost of the processEUR 378,000

Cost per invoiceEUR 10.50

Full-time people7.2

Scenario: hours freed2,880 h

Scenario: cost freedEUR 86,400 (1.6 people)

The formula, with no black boxes

base_hours       = invoices × minutes_per_invoice ÷ 60
exception_hours  = invoices × %_exceptions × minutes_per_exception ÷ 60
total_hours      = base_hours + exception_hours
annual_cost      = total_hours × cost_per_hour
cost_per_invoice = annual_cost ÷ invoices
people           = total_hours ÷ hours_per_person_per_year

scenario: hours_freed  = invoices × (1 − %_exceptions) × %_scenario × minutes_per_invoice ÷ 60
          cost_freed   = hours_freed × cost_per_hour
          people_freed = hours_freed ÷ hours_per_person_per_year

The calculator uses no external figure: every number comes from the fields and you can change it. The starting values are round assumptions for a mid-sized group, not market averages or results of any customer.

The starting calculation, step by step

Step	Calculation	Result
Hours with no issues	36,000 × 12 ÷ 60	7,200 h
Exception hours	36,000 × 20% × 45 ÷ 60	5,400 h
Total hours	7,200 + 5,400	12,600 h
Annual cost	12,600 h × EUR 30	EUR 378,000
Cost per invoice	EUR 378,000 ÷ 36,000	EUR 10.50
Full-time people	12,600 h ÷ 1,760 h	7.2
Scenario: hours freed	36,000 × 80% × 50% × 12 ÷ 60	2,880 h
Scenario: cost freed	2,880 h × EUR 30	EUR 86,400

The most useful reading of the example is not the total but its split: exceptions are 20% of the invoices and take 43% of the hours. Reducing the number of exceptions (with more purchases on a purchase order and recorded delivery notes) usually moves the cost more than speeding up the recording of invoices that already match.

Want to see it with your own invoices? Request a demo with your own invoices

How to choose each assumption

Minutes per invoice. Measure it with a sample: time 20 normal invoices end to end, from arrival until they are ready to pay, and use the average.
Exception rate. Count, over one month, the invoices that could not be approved first time for any reason. If there is no record, that is already a finding.
Minutes per exception. Include the time of purchasing, the warehouse and the approvers, not only that of the accounts payable team. It is the part of the cost that is most often underestimated.
Cost per hour. Use the employer cost (salary plus social charges) divided by the effective hours of the year.
Scenario. It is a question, not a promise: "what would happen if half of the invoices that already match no longer needed a person?". Enter the percentage you consider prudent for your company.

What this calculator does not measure

Money paid in excess. An invoice that charges more than the purchase order price, or a quantity that was not received, does not cost minutes: it costs its difference. The invoice and delivery note reconciliation guide works through invoices that do not match, with the difference in euros.
Duplicate payments. See how duplicate invoices are detected.
The new work of mandatory B2B e-invoicing in Spain. According to the Spanish Tax Agency calendar, from 6 October 2027, 2028 or 2029, depending on the bracket, the recipient will have to report the rejection and the payment of each invoice (Royal Decree 238/2026, articles 10 and 12). See the e-invoice reception guide.
The cost of the tool. ininvoice does not publish prices: it prepares a tailored proposal based on volume, companies and ERP (how the proposal is prepared).

Frequently asked questions

How is the cost per supplier invoice calculated?

The annual cost of the accounts payable process (hours of the team and of the people who resolve exceptions, at their hourly cost) divided by the invoices received in the year. The calculator on this page applies that formula to the assumptions you enter.

Where do the starting values come from?

They are round assumptions for a mid-sized group, not market averages or customer results. They are there so the calculator shows an example; every one of them can be changed.

Does the calculator store my data?

No. The calculation runs in the browser and the figures you type are neither sent nor stored; only the fact that someone used the calculator is recorded.

Why does it not calculate the return on investment?

Because the return depends on the price of the tool, and ininvoice prepares tailored proposals based on volume, companies and ERP. The calculator gives the current cost and a scenario of freed hours with the percentage you choose.