Short answer: if you need pipeline in the next quarter, an outbound agency gets you there faster and cheaper to start. An in-house SDR wins later — once your sales motion is proven and you’re past roughly £3–5M ARR. The decision isn’t about budget. It’s about what stage you’re at.
Here’s the honest maths on both, and the exact point where the answer flips.
Key takeaways
- A fully-loaded in-house SDR costs roughly £75k–£100k a year and takes about 3 months to ramp before they produce real pipeline.
- An outbound agency typically runs £4k–£7k a month, starts outreach in 2–4 weeks, and carries no hiring or attrition risk.
- Agencies win on speed and risk early. In-house wins on control and cost once your motion is repeatable.
- Neither fixes a weak offer or a vague ICP. Sort that first or both will underperform.
What does an in-house SDR actually cost?
More than the salary line. A sales development rep in the UK might have a base of £35k–£45k, but once you add commission, employer taxes, tooling (data, sequencer, LinkedIn Sales Navigator), onboarding and management time, the fully-loaded cost lands closer to £75k–£100k a year. US teams run higher again — The Bridge Group’s SDR research puts fully-loaded cost north of $95k.
Then there’s ramp. The Bridge Group pegs SDR ramp at around three months, and that’s after you’ve spent a month or two hiring. So from “let’s hire” to “consistent booked meetings” is realistically four to five months.
You’re also carrying the risk. SDR tenure is famously short. If they leave at month nine, you eat the ramp cost again.
What does an outbound agency cost?
A specialist outbound or appointment-setting agency typically charges £4k–£7k a month. A full go-to-market partner running strategy, outbound and the systems behind it sits higher — up to around £15k depending on scope.
The difference is what you skip. No hiring cycle, no ramp, no tooling to buy, no attrition risk. A good agency already has the data sources, the sending infrastructure and the playbooks. Outreach usually starts inside 2–4 weeks, with first meetings landing in 30–45 days.
Which one fills your pipeline faster?
The agency, clearly, in the early days. Two to four weeks to first outreach versus four to five months to a productive in-house hire isn’t close. If the goal is “we need qualified conversations this quarter,” that gap is the whole decision.
Speed matters more than it looks, because most of your market can’t buy today anyway. Only about 5% of B2B buyers are in-market at any given time (Prof. John Dawes, Ehrenberg-Bass Institute, via the LinkedIn B2B Institute). The faster you’re in front of that rolling 5%, the sooner pipeline compounds.
So when should you hire in-house instead?
When three things are true:
- Your motion is proven. You’ve booked and closed enough deals to know your ICP, your message and your objections cold. You’re handing a rep a script that works, not asking them to find one.
- You’re past roughly £3–5M ARR. You can absorb the ramp cost and the risk of a bad hire without it hurting.
- You’ll actually manage it. SDRs need coaching, call reviews and a clear career path. If nobody owns that, the hire fails regardless of talent.
Owning it in-house is the right long-term play once the motion is repeatable. You keep the muscle, the data and the institutional knowledge. The mistake is reaching for it before you’ve proven the motion — then you’re paying someone to figure out something you don’t know yourself.
The hybrid most people miss
You don’t have to choose forever. A common setup: an agency runs top-of-funnel outbound to fill the calendar, while your in-house team owns discovery, qualification and closing. The agency proves the motion and hands you a playbook; you bring it in-house when the economics say so. Done right, the agency is training your future team, not replacing it.
The real mistake founders make
They decide by budget instead of by stage — and they expect either option to fix a broken funnel. It won’t. If your ICP is vague or your offer is soft, more outreach just spreads a weak message wider. Pick one ICP first, tighten the offer, then decide who runs the outreach.
How we think about it at Ascent
We run outbound as one system with one point of accountability — strategy, targeting, infrastructure and the sending, owned end to end. We’ll also tell you when it’s time to bring it in-house. We’re not trying to keep you on a retainer forever; we’re trying to build you a pipeline that holds up. If you want a straight read on which path fits your stage, book a call and we’ll talk it through.
Common questions
Is an outbound agency worth it?
Yes, if you need pipeline quickly and your offer and ICP are clear. An agency gets you to booked meetings in weeks rather than months, with no hiring or attrition risk. It’s not worth it if you’re using it to avoid figuring out who you sell to — that’s a strategy problem no vendor can solve for you.
How much does an outbound agency cost per month?
Most specialist outbound agencies charge £4k–£7k a month. A full go-to-market partner that also owns strategy and infrastructure can run up to around £15k, depending on scope.
How long before an agency starts booking meetings?
Outreach usually starts within 2–4 weeks, once targeting and sending infrastructure are set up. First meetings typically land in the following 30–45 days.
When should I hire an in-house SDR instead?
Once your sales motion is proven, you’re past roughly £3–5M ARR, and you have someone to manage and coach the role. Before that, you’re paying for ramp and risk on a motion you haven’t nailed down yet.
Can I run an agency and in-house together?
Yes, and it’s often the smartest setup. Let the agency run top-of-funnel outbound while your team owns qualification and closing, then bring outbound in-house once the playbook is proven.