In-house marketing vs agency: the hire, against revenue

In-house marketing vs agency is usually argued as salary against fee. For a brand that already sells online and runs marketing with one to three people, the useful comparison is each option as a share of online revenue. Below a certain revenue, the in-house hire is the most expensive line in the business.

A salary leaves out what the employer pays on top. A fee means nothing until it is set against what the store sells. Put both over the same revenue and the decision stops being a matter of taste.

This post prices one growth hire in Spain, sets it against a worked store and gives the revenue line where the hire starts to make sense.

In-house marketing vs agency is decided by each option's annual cost as a share of online revenue. One growth manager in Spain costs about €58,200 a year with employer contributions: 28.5% of a store selling €204,000 online. The hire only shrinks to what typical companies spend on marketing staff from about €3.45M.

Key takeaways

• Compare in-house marketing vs agency as a share of online revenue, not as salary against fee.
• A growth manager in Spain averages €44,736 a year; with employer contributions of about 30%, the hire costs about €58,200.
• On a store selling €204,000 a year online, that one hire is 28.5% of revenue and 3.7 times a typical marketing budget.
• To cover its own cost in revenue, the hire has to lift conversion from 1.0 to about 1.29 orders per 100 sessions in year one.
• Divide salary × 1.30 by your online revenue, and run any agency quote through the same line before choosing.

In-house marketing vs agency: the wrong comparison

The usual version of this decision puts a salary next to a monthly fee and picks the smaller number. It fails twice. The salary is not what the hire costs, because the employer pays contributions on top. And neither number means anything until it is set against what the store sells online.

A brand with one to three people in marketing feels the second part most. Every euro of fixed cost comes out of the same online revenue that pays for ads, stock and the next launch. The right unit is the share: annual cost divided by annual online revenue, for the hire and for the agency alike.

Share of revenue = annual cost ÷ annual online revenue × 100

What a growth hire really costs

Start with the salary. Jooble, a job search engine, puts the average growth manager salary in Spain at €44,736 a year, or €3,728 a month, with a range from €29,448 to €64,008, on job offers as of 29 July 2026.

Then add what the employer pays. Spain's Social Security lists the company's share for 2026 as 23.60% for common contingencies, 5.50% for unemployment on a permanent contract, 0.20% for the wage guarantee fund and 0.60% for training. That adds up to 29.90%, before a work-accident premium that depends on the activity and that the employer pays alone. Round it to 30%:

Annual cost of the hire = salary × 1.30
€44,736 × 1.30 ≈ €58,200 a year, about €4,850 a month

Use the salary the role would actually be offered. A senior hire near the top of the range, at €64,008, costs about €83,200 a year once the 30% is added. A junior one near €29,448 costs about €38,300, and usually needs someone senior to decide what to work on.

That figure still leaves out the laptop, the tools, the months spent hiring and the months before the new person knows the store. None of it shows up on a payslip. All of it comes before the first result.

The hire on a €204,000 store

The worked store this blog uses, as an example: 300,000 sessions a year, a €68 average order and 1 order for every 100 sessions. That makes 3,000 orders and €204,000 of online revenue a year.

Share of the hire = €58,200 ÷ €204,000 × 100 ≈ 28.5%

Out of every €100 the store sells online, about €28.50 goes to one person before a single product ships.

Gartner's 2025 CMO Spend Survey of 402 marketing leaders, as Chief Marketer reported it, puts marketing budgets at an average of 7.7% of total revenue. On this store, that would be about €15,700 a year for all of marketing: ads, tools, content, people and agencies together. The single hire costs 3.7 times that.

Then the hire has to earn its cost back. At €68 an order, €58,200 is about 856 extra orders a year. On 300,000 sessions, that means 0.29 more orders per 100 sessions, from 1.0 to about 1.29, in year one. That is counted in revenue, before any margin. A tenth of a point on this store is worth €20,400 a year, so the hire needs almost three of them just to cover itself.

Before choosing either option, a Conversion Audit ranks the first decisions on the store's own numbers, in five business days.

Run the agency quote through the same line

An agency is priced the same way. Ask what the fee includes: the hours, the people and who decides what gets worked on. Then take the quote, multiply the monthly fee by 12 and divide by online revenue. A quote of €2,000 a month, as an example, is €24,000 a year: 11.8% of the worked store. That is lower than the hire, and still above the 7.7% a typical company spends on all of its marketing.

Gartner's survey also splits that budget: labor takes about 22 of every 100 marketing dollars, and agencies about 21. On a store this size, the problem is not the hire or the retainer on its own. It is any fixed monthly cost of that weight, paid before anyone knows where the store loses orders.

What the money buys matters as much as the amount. A retainer billed for tests the traffic cannot finish is the trap that a conversion rate optimization agency's pricing hides. A hire with no target for customer acquisition cost is a salary looking for a job.

In-house marketing vs agency: the revenue line

The same formula, solved for revenue, says when the hire starts to make sense:

Revenue line = annual cost of the hire ÷ the share of revenue you accept

Two lines come out of the survey's own numbers:

• €58,200 ÷ 0.077 ≈ €756,000. Below that online revenue, one growth salary costs more than a typical company's whole marketing budget.
• €58,200 ÷ 0.077 ÷ 0.219 ≈ €3.45M. Only from there does the hire shrink to the share typical companies spend on all their marketing staff, about 1.7 of every 100 euros of revenue.

Between those two lines, the question is which seat is empty, and the fractional CMO or growth team comparison sorts it with four questions. Below the first line, the hire is the most expensive line in the business. The work that comes first is finding where the store loses orders, which is what a UX audit reads and prices.

The number for your own store

Share of the hire = salary × 1.30 ÷ annual online revenue × 100
Conversion it must add = salary × 1.30 ÷ average order ÷ annual sessions × 100

On the worked store: 28.5% of revenue, and 0.29 more orders per 100 sessions in the first year.

What to do by Monday: take the salary you would offer, multiply it by 1.30 and divide by last year's online revenue. Do the same with the agency quote on your desk. If either result is above the 7.7% a typical company spends on all of marketing, the store is not ready for that fixed cost yet. The first euro goes to finding where it loses orders.

Work through this with your own numbers

I run an online store that sold [annual online revenue] last year, from [annual sessions] sessions at an average order of [average order value]. I am choosing between hiring a growth person in-house at a salary of [salary offered] and an agency that quoted [monthly fee] a month. Calculate the annual cost of the hire as salary × 1.30, to include employer contributions, and the agency's annual cost as the monthly fee × 12. Express each one as a share of my online revenue. Then calculate how many extra orders a year, and how many more orders per 100 sessions, the hire would need to cover its own cost in revenue. Compare both shares with a marketing budget of 7.7% of revenue, and tell me whether my store is ready for either fixed cost or should first find where it loses orders. Show every step of the arithmetic.

FAQ

Is it cheaper to hire in-house or use a marketing agency?

It depends on online revenue, not on the salary or the fee alone. Divide each option's annual cost by annual online revenue. One growth manager in Spain costs about €58,200 a year with employer contributions, which is 28.5% of a store selling €204,000 online and under 2% of one selling €3.45M.

How much does a growth manager cost in Spain?

Jooble puts the average growth manager salary in Spain at €44,736 a year, on job offers as of July 2026. The employer adds about 30% in Social Security contributions, so the annual cost is about €58,200, or €4,850 a month, before tools and hiring time.

At what revenue does an in-house marketing hire make sense?

Solve the share for revenue: annual cost of the hire divided by the share you accept. With Gartner's 7.7% average marketing budget, one €58,200 hire equals a whole typical budget below about €756,000 of revenue, and only reaches the typical share for marketing staff from about €3.45M.

What are the pros and cons of an in-house marketing team vs an agency?

An in-house team knows the brand and stays, but it is a fixed cost that starts before the first result. An agency can start faster and stop, but a retainer billed by the month can pay for work the traffic cannot finish. Either way, compare them as a share of online revenue first.

That's what the Conversion Audit maps: five business days, $500, and the map stays with you whether or not you hire anyone next.