Ask a retail support leader what a contact costs them and you will usually get a number derived from salary divided by contacts handled. That number is wrong by a wide margin, and it is wrong in a consistent direction: it is always too low. Which matters, because it is the number that gets set against a vendor quote in a finance meeting, and the comparison decides the outcome.

This post rebuilds the calculation from public data, shows it on a realistic retail volume, and then sets it against outsourced pricing. It also covers the three situations where the comparison flips and in-house wins.

The four cost lines most retailers leave out

A fully loaded cost per contact has nine components. Most internal calculations include five. The four that get dropped are the four that move the number most.

Building the retail cost per contact properly

Step 1: the fully loaded hourly cost

The US Bureau of Labor Statistics publishes both halves of this. The Occupational Outlook Handbook puts the median hourly wage for customer service representatives at $21.53 as of May 2025, across 2,666,000 US jobs. The Employer Costs for Employee Compensation release for June 2026 shows that for office and administrative support occupations in private industry, wages account for 68.7% of total compensation and benefits for 31.3%.

Benefits therefore add 45.6% on top of wages, a multiplier of 1.456. Applied to the median wage: $21.53 x 1.456 = $31.35 per hour worked.

A technical note that matters

BLS expresses these costs per hour worked, not per hour paid. Paid leave is already inside the benefits figure and already spread across worked hours. Do not add a separate holiday and sick leave adjustment on top, or you will double-count.

Note also that $31.35 is a derivation from two BLS releases, not a figure BLS publishes. Show your working when you use it.

Step 2: the attrition multiplier

ContactBabel’s 2024 US Contact Center Decision-Makers’ Guide, based on a survey of 189 US contact centre managers and directors, found mean annual agent attrition of 31% and a median of 24%. SQM Group puts agent replacement cost at 30% to 50% of a new agent’s annual salary, covering hiring, training and time to productivity.

Take the conservative end of both. At 24% attrition and a 30% of salary replacement cost, on a $44,770 median annual wage:

• Replacement cost per departing agent: $44,770 x 30% = $13,431
• Annual replacement cost per seat: $13,431 x 24% = $3,223
• Added to hourly cost at 2,080 hours: roughly $1.55 per hour, or a further 5% on the loaded rate.

At the mean attrition of 31% and a 50% replacement cost, the same calculation adds $3.34 per hour. The range between the conservative and the aggressive assumption is more than double, which is why the assumption belongs in the model as a visible input rather than buried in a total.

Step 3: productive hours, not paid hours

An agent paid for 2,080 hours a year does not handle contacts for 2,080 hours. Subtract training, coaching, team meetings, system downtime and the shrinkage that every workforce management plan already accounts for. Most retail support operations land between 65% and 80% productive time. At 75%, your $31.35 hourly cost becomes an effective $41.80 per productive hour before supervision, technology or facilities.

Step 4: the overhead layer

Add supervision at your actual ratio, quality assurance headcount, licence costs per seat, and facilities or remote-equipment cost. These vary enough between businesses that a published benchmark is not useful. What is useful is insisting they appear in the calculation at all, because a vendor quote includes every one of them and an in-house number that omits them is not a comparison.

Worked example: 40,000 contacts a month

A mid-market retailer handling 40,000 contacts a month, at an average handle time of 7 minutes plus 1 minute of after-contact work, needs roughly 5,333 productive agent hours per month. At 75% productive time, that is about 7,111 paid hours, or 41 full-time agents.

Check every assumption in that table

Wages, benefits and attrition are derived from the BLS and ContactBabel sources listed at the end. Supervision ratio, licence cost and facilities cost are illustrative and will not match your business. Replace them before you use this in a board paper. The point of the table is the structure, not the total.

For reference, ContactBabel’s 2026 US guide puts the average cost of an inbound call at $7.20, which is close to the $6.98 above. That is reassuring but not confirmation, because the composition behind ContactBabel’s figure is not disclosed publicly.

The same volume, outsourced

Against a true in-house cost of roughly $7 per contact, the outsourced comparison depends almost entirely on delivery region. Using published 2026 hourly ranges and the same 5,333 productive hours per month:

Read that table carefully, because it is easy to misread. US onshore outsourcing is not reliably cheaper than doing it yourself. The saving in the offshore rows is real and large, and it buys a different service: a different time zone, a different accent profile, and a quality outcome that depends entirely on the vendor’s attrition and training rather than on the hourly rate.

The hourly ranges come from a vendor-published pricing guide, so they are directional. Any serious comparison replaces them with actual quotes on your actual scope.

Where the comparison flips

Three situations where the in-house number wins even at a higher cost per contact.

1. Contacts that generate revenue. If your agents convert pre-purchase conversations into orders at a measurable rate, cost per contact is the wrong metric entirely. Measure contribution per contact instead, and an in-house team with product depth usually wins.
2. Volume below a vendor’s minimum. Under roughly ten full-time equivalents, you pay a minimum commitment and receive shared agents. The unit economics stop working and so does the quality.
3. When the support conversation feeds merchandising. If buying decisions change because of what support hears, the information is worth more than the cost difference. Outsource the delivery and returns volume and keep the pre-purchase conversation.

Seven questions that make a vendor quote comparable

• Is the rate per agent hour, per productive hour, or per contact? These are three different numbers.
• What productive-time assumption sits behind a per-hour quote?
• Are supervision, QA and workforce management inside the rate or billed separately?
• Are technology licences included, and whose platform is it?
• What is the minimum commitment, and what happens to the rate if volume falls?
• How is peak or burst capacity priced, and with how much notice?
• What is the transition cost, and is any part of it billed to us?

The short version

Build your in-house number properly before you look at a single quote. Nine cost lines, an explicit attrition assumption, and productive hours rather than paid hours. Once the real figure is on the table, the outsourcing decision usually gets simpler and occasionally reverses. Either outcome is better than comparing a vendor’s full cost against your partial one.

Sources

• US Bureau of Labor Statistics, Occupational Outlook Handbook, Customer Service Representatives. Median wage $21.53 per hour, May 2025. https://www.bls.gov/ooh/office-and-administrative-support/customer-service-representatives.htm
• US Bureau of Labor Statistics, Employer Costs for Employee Compensation, June 2026, Table 4, office and administrative support, private industry. https://www.bls.gov/news.release/ecec.t04.htm
• ContactBabel, The 2024 US Contact Center Decision-Makers’ Guide, 16th edition, n=189. Attrition data, 2023. https://assets.ringcentral.com/us/report/us-dmg-2024.pdf
• ContactBabel, The 2026 US Contact Center Decision-Makers’ Guide. Average inbound call cost $7.20. https://www.contactbabel.com/the-us-contact-center-decision-makers-guide/
• SQM Group, Call Center Attrition Rate. Replacement cost at 30% to 50% of annual salary. https://www.sqmgroup.com/resources/library/blog/call-center-attrition-rate
• Crescendo, Outsourced Call Center Pricing Guide for 2026. Vendor published, directional only. https://www.crescendo.ai/blog/outsourced-call-center-pricing-guide