Paid Media Budget Allocation: How to Split Spend Across Google and Meta
There is no universal Google-to-Meta split that works across businesses. The right allocation depends on where buyers look when they have your problem, how long they consider before spending, and what conversion data you have to optimise to. This guide gives a practical framework for deciding that split, dividing within each platform, and adjusting allocation as results come in.
- Google captures intent that exists; Meta creates demand. The right mix depends on your search volume.
- Scale the channel with the best unit economics toward its ceiling before heavily investing in the second.
- A working reserve: 70% proven, 20% scaling experiments, 10% new channel tests.
- Review allocation monthly based on four-plus weeks of data, not weekly fluctuations.
Why this matters
Most allocation questions in paid media are answered with guesses justified as conventions: “We split 60/40 between Google and Meta.” The problem is that those conventions do not account for where your specific buyers look when they have your specific problem, which means some accounts are systematically spending where the return is lower without knowing it.
Budget allocation is one of the few decisions in paid media that cannot be automated. Bidding strategies, audience selection, and ad copy can all be delegated to the platform. Deciding where money should go, and in what proportion between capturing existing intent and creating new demand, remains a human judgement that needs data and a consistent framework.
Google vs Meta: what each channel does
| Google Search / Shopping | Meta (Facebook / Instagram) |
|---|---|
| Captures intent that exists now | Creates demand and reaches buyers who are not yet searching |
| Works where buyers search for the category | Works where the product or problem is not widely searched |
| Higher purchase intent at point of contact | Broader audience reach at lower initial intent |
| Performance tied to search volume | Performance tied to creative quality and audience size |
| Higher floor CPCs in competitive categories | Variable CPMs, often more efficient for awareness stages |
Most established businesses have some demand on both channels. The question is which dominates and which plays a supporting role.
The allocation framework
- 01
Measure current cost per acquisition by channel
Get a minimum of four weeks of data with clean tracking before making allocation decisions. Blended CPA across channels hides which one is doing the work. The tracking verification steps are in our measurement guide.
- 02
Establish the LTV ceiling per channel
The maximum you can profitably pay per customer depends on lifetime value and gross margin. If that ceiling is £80, a channel delivering at £120 is unprofitable regardless of volume. Channels delivering well below the ceiling have room to absorb more budget.
- 03
Weight toward the profitable channel first
Scale the channel with the best current cost-per-acquisition toward its ceiling before investing heavily in the secondary channel. Most budget allocation mistakes come from spreading spend too evenly before proving unit economics on the leading channel.
- 04
Apply the 70/20/10 reserve
70% to proven campaigns, 20% to scaling experiments within proven channels (new campaign types, new audience segments), 10% to new channel tests. The 10% test allocation is capped at what the business can write off as learning cost.
- 05
Review and rebalance monthly
Monthly data is the minimum for allocation decisions. Weekly movements are noisy; monthly trends are structural.
Within-platform splits
Within Google: Brand and non-brand should be separated. Brand CPC is lower and conversion rate higher, so blending them hides the true efficiency of non-brand prospecting. A working starting point for non-brand Google spend is roughly 60% Search, 30% Shopping (for e-commerce), 10% Performance Max, adjusting as data comes in. For lead generation without e-commerce, the PMax allocation warrants its own analysis using the PMax controls framework.
Within Meta: Advantage+ as the primary campaign structure with exclusions for existing customers and retargeting audiences receiving their own campaigns. Cold prospecting and retention should not share the same budget pool because the bidding behaviour differs and the creative requirements are different. The full Meta structure is in the Andromeda playbook.
Adjusting as you scale
The allocation that works at £5,000 per month does not automatically work at £20,000. As budgets scale, search volume ceilings come into view on Google (you can only capture so many searches), and Meta’s audience size becomes more important. At higher budgets, the within-platform mix typically shifts: more Meta to reach audiences beyond the search-active segment, more PMax and AI Max to capture adjacent intent on Google. These are not fixed rules but patterns to test against as scale increases. Our paid media management service handles the structural decisions and the weekly pacing adjustments across both platforms.
Frequently Asked Questions
Start with the channel that captures existing demand. If people search for what you offer when they need it, Google Search captures that intent at the moment it exists. If your product or service is not widely searched, or if you need to create awareness of a problem before selling a solution, Meta is more efficient at reaching audiences who do not yet know they need you.
A working rule is to keep 70 to 80% of spend on channels that are performing to known benchmarks, 15 to 20% on scaling what is working (new audiences, new campaign types within proven channels), and 5 to 10% on genuinely new channel experiments. The testing allocation should be capped at what you can afford to lose without affecting operational revenue.
Monthly for distribution between channels, based on the previous month’s cost per acquisition by source. Weekly for within-platform pacing. Any allocation review should use data over at least four weeks, since short windows are distorted by day-of-week and algorithm learning effects.
First distinguish between a channel problem and a tracking or targeting problem. If cost per acquisition has risen on one channel while it held on others, check whether tracking changes, audience saturation, or increased competition explains the shift before reallocating budget. Reallocating too early removes the learning investment in the underperforming channel.
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