How to calculate content agencies return on investment

What to take away

Return on investment for a content agency is the value of the business results a campaign produces, minus everything you paid the agency including fees and VAT, divided by those costs.

Start with a baseline before any agency touches the account

You cannot show a return without a starting position. Pull twelve months of the numbers that matter to your business: enquiries, conversion rate, average order value, organic sessions, branded search. Record them in one dated sheet. For a fuller treatment of what each line should contain, read the costs and budget guide.

Map every cost the agency arrangement creates

Agency fees are only part of the picture. Add media spend, software subscriptions, internal hours spent briefing and reviewing, and production costs such as photography.

VAT changes the real cost depending on your VAT status. Current rates are published on the VAT rates page, and standard-rate VAT applies to most agency services. If you can reclaim it, exclude it and say so; if you cannot, include it, because that money has left the business.

Choose one attribution method and hold it

Attribution is where return calculations fall apart. Pick one and write down why:

Apply your chosen method to the baseline period as well as the campaign period. A method used only on the new work will flatter the agency. Where the work touches consumer-facing offers, the Consumer Rights Act 2015 sets the standards your contracts and claims must meet.

Do the arithmetic and sanity-check the result

The formula is simple: value created minus total cost, divided by total cost. If a campaign generated £40,000 in tracked revenue and cost £10,000 all in, the net return is 3:1, or £3 for every £1 spent.

State the period and whether the figure is gross or net. Then test it. Does the result survive if you remove the best month, and does it hold under your second-choice method? If it collapses, say so before someone else does.

Check the agency's own advertising claims

Agencies advertise results, and some practices attract regulatory attention. The list of non-compliant online advertisers is a reasonable starting point when checking a shortlist.

Treat headline case studies as claims to verify, not evidence. Ask the agency for a reference, then ask that reference how the return was measured.

For help assembling defensible figures, the cost guide data and sources explains where the numbers come from.

Review and report on a fixed rhythm

Set a monthly review and a quarterly recalculation: each month update actual spend against budget and record any scope changes, because scope creep quietly destroys returns.

Each quarter rerun the full calculation from baseline to present, keeping a version history. If the return falls below your agreed threshold for two consecutive quarters, renegotiate or exit rather than wait another year.

Return on investment checklist

Common questions

What counts as a good return on content agency spend?

There is no universal threshold. Set yours from your own gross margin and payback period, then compare proposals against it.

Should I include internal staff time in the cost base?

Yes. Briefing, reviewing and approving work consumes salaried hours, and leaving them out hides the true cost of managing the relationship.

How often should the calculation be rerun?

Quarterly at minimum, using the same method each time. Monthly updates help with budget control, but a full calculation needs enough data to be meaningful.

What if the agency disagrees with my attribution method?

Agree the method in writing before work starts, including how disputed results are reviewed. If the agency prefers another method, ask for the calculation both ways so the difference is visible.