Back to the Agency vs In-house Cost Modeler guide
Agency vs In-house Cost Modeler
Most comparisons put a salary next to a retainer and stop there. This one loads both sides properly, counting employer burden, recruitment, ramp, tooling, attrition and the management time nobody books, then prices the hybrid too.
Agency vs In-house Cost Modeler
LivePrices all three routes properly, including employer burden, recruitment, ramp, tooling and the management time nobody books. Most comparisons stop at salary versus retainer, which is why most of them are wrong.
In-house team
$1.9M
$51,524/mo avg · 100% coverage
Agency retainer
$689k
$19,149/mo avg · 100% coverage
Hybrid (in-house lead + agency delivery)
$1.4M
$37,786/mo avg · 100% coverage
Cumulative cost
Where the lines cross is the month the cheaper route changes. Below that month, the ranking above is reversed.
In-house teamAgency retainerHybrid (in-house lead + agency delivery)
The agency route stays cheaper across the whole horizon
Loaded properly, with burden, recruitment, tooling and management time included, the in-house team does not overtake the retainer inside 36 months. Retain the agency, but negotiate knowledge transfer into the contract so you are not renting institutional memory indefinitely.
Where the money goes
The lines that get left out of a napkin comparison are usually the ones that decide it.
In-house team
Salaries + employer burden
28% burden on 4 roles
$1.6M
Recruitment
18% of first-year salary, incl. replacements
$111k
Tooling & data
$65k
Management time
12 hrs/mo of leadership time
$52k
Total over 36 months
$1.9M
Agency retainer
Retainer
5% annual escalation
$619k
Onboarding / strategy fee
$12k
Pass-through tooling & media fees
$32k
Your management time
6 hrs/mo
$26k
Total over 36 months
$689k
Beyond cost
Two routes at the same price are not the same decision.
| In-house | Agency | Hybrid | |
|---|---|---|---|
| Total cost | $1.9M | $689k | $1.4M |
| First-year cost | $671k | $228k | $468k |
| Cost of first 6 months | $388k | $119k | $256k |
| Months to full output | 5 | 1 | 5 |
| Capability coverage | 100% | 100% | 100% |
In-house team
- Institutional knowledge compounds inside the business rather than inside a vendor
- Full-time attention and same-day turnaround on priorities
- Cost per hour falls every year the team stays
- Each departure costs a replacement fee plus 4 months of ramp
- Capability gaps require another hire, not a phone call
- Fixed cost that does not flex down when the plan changes
Agency retainer
- Full capability set live in weeks, not quarters
- Cost flexes with the contract instead of the payroll
- Pattern recognition from work across many comparable accounts
- Knowledge leaves with the contract
- Your account team is shared, and priority follows the largest client
- Retainer escalates annually while the scope quietly stays flat
Hybrid (in-house lead + agency delivery)
- Strategy and accountability stay in-house; execution capacity flexes
- An internal owner keeps agency work honest and briefed properly
- Cheapest route to full capability coverage in the first year
- Requires a strong internal lead, because the model collapses without one
- Two cost centres to manage, and a boundary that has to be policed
- Handoffs between internal and agency work add coordination overhead
Per-role salary overrides
$
4 month ramp · agency equivalent $6,500/mo
$
2 month ramp · agency equivalent $5,500/mo
$
3 month ramp · agency equivalent $4,800/mo
$
2 month ramp · agency equivalent $4,200/mo
The number this model cannot give you
Cost is the easy half. The hard half is whether the work gets done well, and that depends on who is accountable for it. An agency with a weak internal counterpart produces activity rather than outcomes; an in-house hire without senior support produces the same. Whichever route the arithmetic favours, budget for one person whose job is to own the outcome: 9 distinct capabilities need someone holding them together.