Looking beyond the salary line
Let’s start with a common scenario: hiring a senior HR leader, perhaps a Head of HR or HR Director, on a £100,000 base salary.
For many stakeholders, that’s where the cost conversation begins and ends.
But in practice, HR leaders know the fully loaded cost tells a different story:
- Employer National Insurance (15%) adds around £14,250
- Bonus expectations (typically 20–25%) add £20,000 to £25,000
- Pension contributions, healthcare and benefits often add another £10,000 to £20,000
- Holiday entitlement (28+ days plus bank holidays) equates to roughly 10 to 12 percent of paid time not worked
- Sick pay and absence exposure introduce further variability
- Onboarding, hiring and potential relocation costs add further investment
When you aggregate those elements, that £100,000 hire often sits closer to £165,000 to £180,000 or more in real annual cost.
That is before considering performance risk or the cost of change if things do not land as expected.
Why interim HR feels expensive, but often is not
Interim HR support operates on a very different cost model.
Yes, the day rate is typically higher than a pro-rated salary. But structurally:
- You only pay for days worked, with no holiday or sick pay
- There are no employer on-costs, such as National Insurance, pensions or benefits
- Bonus structures do not apply, as delivery is expected as standard
- Notice periods are shorter, often around one month
- There is no long-term employment liability
In simple terms, cost becomes far more tightly aligned to delivery and duration.
This is particularly relevant in HR, where the need is often time-bound rather than permanent:
- Leading a transformation programme
- Managing a period of organisational redesign
- Supporting complex employee relations or change activity
- Covering leadership gaps during hiring cycles
- Integrating after mergers or acquisitions
These are not always roles that need to exist indefinitely, but they do require credibility and pace when they do.
The bigger consideration: hiring risk
In most conversations with HR leaders, cost is only part of the equation.
The more difficult and often more expensive issue is risk.
- Hiring permanently into a structure that is still evolving
- Committing to headcount before budgets are fully secure
- Rushing a leadership hire to fill a gap quickly
- Managing the impact of a mis-hire at senior level
These are the moments where interim HR support becomes less about resource and more about risk management.
A strong interim can:
- Create stability quickly, without long-term commitment
- Deliver critical outcomes during periods of uncertainty
- Give you time to hire properly, rather than quickly
- Reduce the financial and cultural cost of getting it wrong
In many cases, that risk mitigation is where the real commercial value sits.
Flexibility as a strategic lever
One of the more interesting shifts over the past few years is how organisations are choosing to use interim HR. It is no longer purely reactive, but increasingly planned.
Rather than asking, “Is an interim cheaper than a permanent hire?”, the question becomes:
Where do we need permanence, and where do we need flexibility?
Because they serve different purposes.
A permanent HR leader brings continuity, cultural ownership and long-term capability.
An interim brings:
- Immediate impact
- Objective perspective
- Freedom to focus on delivery over internal politics
- The ability to step in and step out exactly when needed
Used together, they create a more resilient HR function.
A more balanced commercial view
It is important to be clear: interim HR is not a shortcut or a cheaper substitute for permanent capability.
Nor should it be treated as one.
But equally, it is not simply a premium option reserved for crisis situations.
In many cases, it is a financially and strategically sound choice when:
- The outcome is clearly defined
- The timeframe is finite
- The risk of a permanent mis-hire is high
- The organisation needs speed without long-term commitment
When you compare a £165,000 to £180,000 fully loaded permanent cost with a defined period of high-impact interim delivery, the gap is often narrower than expected and, importantly, more controllable.
Bringing it back to what matters
For HR leaders, this ultimately comes down to balancing three things:
- Cost, not just salary but total investment
- Risk, both financial and organisational
- Outcomes, what needs to be achieved and by when
Interim HR support sits at the intersection of all three.
And when used deliberately rather than reactively, it can protect both budget and delivery in ways that are not always obvious at first glance.
In practice, the most effective HR teams are not choosing between interim and permanent.
They are building a model that allows them to move between the two confidently, depending on what the business needs at that moment.
And in the current climate, that flexibility is often where the real value lies.
Opening up the conversation
There is rarely a one-size-fits-all solution here, and the nuance tends to sit in the detail of each organisation’s context.
If you are weighing this up at the moment, I am always happy to compare thinking and share what I am seeing across the market so please get in touch for a confidential conversation.
Find my contact information, or book a meeting with me here.
