I have hired a lot of SDRs in-house over the last 18 years. The first ten taught me how to do it. The next thirty taught me how to do it badly without realising. The thing nobody tells you when you make the hire is that the salary is not the whole cost.
I want to make the case both ways here. There is a strong, honest argument for hiring SDRs in-house, institutional knowledge, brand voice, full control of the pipeline function. There is also a strong, honest argument against, five costs most CFOs miscalculate that compound across the first year of a programme.
The five costs that get missed
Recruitment. The CIPD puts the median cost per hire for a non-senior private sector role at £2,000. Then there is your senior team's time on shortlisting, interviewing, reference-checking and onboarding, which never shows up on an invoice.
Ramp. The Bridge Group's 2025 SDR report puts ramp at 3.0 months, so the first quarter of the year-one spend pays for a rep who is still learning the job. If you forget this in the model, you are quietly flattering the in-house case.
Tech and data. Data, a sequencer, a dialler and LinkedIn Sales Navigator come to about £3,770 a seat a year on our estimate from vendor list prices, and a laptop, phone and desk add about £1,000. They are small lines next to the salary, and most internal cost models still forget them entirely.
Manager bandwidth. Every SDR needs a manager for 1:1s, pipeline reviews, call coaching and performance management. The Bridge Group's 2025 report puts the average span at 6.4 reps per manager, and the ONS puts median sales manager pay at £57,625, or £66,840 once employer costs are added. Spread across 6.4 reps, that is £10,440 of management cost per SDR per year. Done badly, you save the management cost and pay it back twice in attrition.
Attrition. The Bridge Group's 2025 report puts average SDR tenure at 1.9 years. When someone leaves, you pay the recruitment line again and sit through the ramp again, so expect to pay for both within two years.
Stack all of this honestly, with employer National Insurance and pension on top of the salary, and an entry-level SDR on £40,000 on-target earnings outside London costs £63,473 in year one. An experienced SDR on £52,000 costs £77,581. Every line, with its source, is in the model on our lead generation pricing guide.
What the maths looks like, side-by-side
We built that model because I kept seeing the same conversation with founders: they would compare an agency retainer to an SDR's salary and conclude in-house was obviously cheaper. The retainer was the full cost. The salary was not. On the model, £40,000 of on-target earnings becomes £63,473 in year one, and that is cost, not output.
The five missing costs above are what most in-house calculations leave out. Add them honestly and most founders finish with a different mental model than they started with.
When in-house is genuinely the right call
I do not run an outbound agency to convince everyone to outsource. In-house is the right call when:
You have a senior sales leader with real bandwidth to manage and coach. The number-one predictor of in-house SDR success is having someone in the building who has done it before. Without that person, the function drifts.
Your product needs deep technical or domain expertise to sell well. Outsourced SDRs are good at qualified curiosity. They are not good at deep technical demos. If your sales motion needs the SDR to understand your product at depth, you need them on the inside.
Your brand voice is part of the moat and you do not want it filtered through anyone else. Some founders have a strong, distinctive way of talking to their market and the SDR work needs to sound like the founder. Done in-house, this is achievable. Done at agency arm's length, harder.
Your average deal size is large enough that one closed deal pays for the SDR's full year-one cost, not just the salary.
When outsourced is the right call
You need pipeline now. With ORRJO, outreach begins within 2 weeks of kickoff, and first qualified meetings typically land within 2 weeks of launch. In-house, you recruit first and then ramp, and The Bridge Group's 2025 SDR report puts ramp alone at 3.0 months. If your runway or your board pressure does not allow a hiring process plus a quarter of ramp at full SDR cost, the choice is made for you.
You don't have a senior sales leader who has run an SDR team before. Hiring SDRs without an experienced manager is the single most reliable way to set them up to fail. Better to outsource until you have built the in-house leadership.
You want to test a new market or segment before committing to permanent headcount. Outsourcing is a way to validate that the market responds before you put fixed cost on the books.
Your team is small enough that the recruitment, management, and infrastructure tax of building in-house is disproportionate. Below ~10 SDRs, the agency model usually has better unit economics.
The honest summary
Both paths work. Both fail. The choice is rarely the one that gets made on a single-line CFO comparison. The five costs above are what most internal models miss, and the five conditions above are what most decisions skip. Run the maths properly, decide deliberately, and most of the agonising goes away.
If you want a senior pair of eyes on your specific situation, internal or outsourced, no preference, book a 30-minute call. We will tell you honestly which way the maths runs for you, and if it is in-house, we will help you sequence the build.
