Paid Media Planning
Paid media budget planning: start with the constraint, not the channel split.
A media plan is more useful when the budget, expected outcome and assumptions connect. This guide shows a practical way to move from a business target to campaign-level budget decisions without pretending a spreadsheet can predict the auction.
Start with the business objective and the real constraint
“How should we split £20,000 between Meta and Google?” sounds like a channel question, but the useful answer depends on what the budget is expected to do. The same £20,000 can support very different plans if the objective is 400 leads, 100 customers, £80,000 in attributed revenue, or simply maintaining impression share.
Write down the outcome, time period and constraint first. The constraint might be allowable CPA, required ROAS, inventory, lead-processing capacity, search demand, audience size or the amount of conversion signal a platform can realistically use.
Reverse-engineer a first budget from CPA or customer economics
If the business has a defensible allowable CPA, a simple first-pass budget is:
That is not a forecast. It is a funding requirement under the assumption that the target CPA is achievable at the intended scale. If historical CPA is £48, the plan should not quietly assume £35 without explaining what changes are expected to close the gap.
When CPA is unknown, build the plan from the funnel
For a traffic-led forecast, impressions, clicks and conversion rate can be chained together:
This is useful for scenario planning because each assumption can be challenged separately. If the forecast requires a 4% CTR when the account normally runs at 1.5%, the problem is visible.
When the funnel is uncertain, show a base case and at least one weaker and stronger scenario.
Split budget by opportunity and role, not by the number of channels
Equal allocation is easy to explain but rarely reflects market opportunity. Search may have limited demand but high intent. Meta may have broader scale but require more creative supply. Retargeting may be efficient but unable to spend much without saturating the audience.
A useful allocation review asks:
- Which channel has enough addressable demand or audience to spend the allocation?
- Which channel has the strongest evidence of incremental or qualified outcomes?
- Where is the next unit of budget likely to be constrained by rank, audience, creative or inventory?
- Which campaigns are strategically necessary even if their direct attribution is weaker?
The Budget Split Calculator is useful for making the allocation explicit, but the percentages still need a reason behind them.
Assume marginal efficiency changes as spend scales
Doubling budget rarely doubles conversions indefinitely. Higher spend can push into weaker queries, less responsive audience segments, higher frequency or more expensive auctions. That is why budget planning should include a diminishing-returns case rather than only a linear case.
PaidMediaKit's Forecasting Planner uses a user-defined scaling-efficiency assumption to make this explicit. It is not a universal benchmark. It is a way to test how the plan behaves if conversion growth is slower than budget growth.
Use scenarios to expose the assumption that matters most
Use realistic recent CPM, CTR, CVR or CPA.
Useful for showing budget risk before launch.
Make the required change measurable rather than aspirational.
If the plan only works in the improvement case, that should be visible before the budget is committed.
After launch, switch from planning to pacing and reforecasting
A budget plan becomes useful only if actual spend and performance are compared with it. Pacing tells you whether spend is ahead or behind the expected run rate; performance tells you whether spending the remaining budget still makes sense.
Review both together. An under-pacing campaign with strong CPA may need more reach, bids, budget access or inventory. An over-pacing campaign with weak economics needs a different response than one that is simply spending quickly during a high-value promotion.
Use the Budget Pacing Calculator and theBudget Pacing Guide once the plan is live.
Common budget-planning mistakes
Assuming 50% more budget means 50% more conversions ignores marginal efficiency.
Channel plans should acknowledge overlap, lag and different attribution rules.
A mathematically attractive allocation is useless if search demand or audience capacity cannot absorb it.
CPA, ROAS, volume, quality and strategic role can point in different directions.