Your PPC Budget Split Is Probably Wrong
Most businesses arrive at their channel budget split the same way. They start with one platform, usually Google Ads, and run it until someone suggests they should “diversify.” So they take a chunk of the existing budget, hand it to a second platform, and call it multi-channel strategy.
The problem isn’t the instinct. Running paid media across multiple channels is the right move for most businesses past a certain size. The problem is how they divide the money. Equal splits. Gut-feel percentages. Whatever was left over after the primary channel took its share. Almost nobody works backwards from what each channel actually needs to function.
And that’s how you end up funding five channels properly enough to generate dashboards but not properly enough to generate results.
The Minimum Viable Spend Problem
Every advertising platform runs on machine learning. The algorithms need conversion data to learn who your customers are and how to find more of them. Below a certain volume of conversions, the algorithm is guessing. And guessing is expensive.
This creates a hard floor for every channel in your mix. There’s a minimum level of spend below which the platform simply cannot optimise. Meta calls it the learning phase. Google bakes it into Smart Bidding. LinkedIn has the same dynamic, just with higher costs per click that push the floor even higher.
I’ve written about this in detail in how many advertising channels you can really afford. The short version: if your budget allocation leaves any channel below its minimum viable spend, you’re not testing that channel. You’re donating to it.
This is the first principle of budget allocation. Before you decide percentages, work out the minimum each channel needs to clear its learning phase and generate enough data to optimise. If you can’t fund a channel above that floor, don’t fund it at all. Two channels running properly will always outperform four channels starving.
Why Equal Splits Don’t Work
The most common budget allocation mistake is treating channels as interchangeable. A business decides to run Google Ads, Meta, and LinkedIn, splits the budget into thirds, and expects each platform to deliver proportional results.
But channels don’t serve the same function. Paid search captures existing demand: people who already know they have a problem and are actively looking for a solution. Paid social creates demand: reaching people who weren’t looking but match your customer profile. Display and video build awareness that feeds everything else downstream.
Each function has different economics. Search tends to convert at higher rates with shorter paths to purchase. Social operates on longer timescales with more touchpoints before conversion. Awareness channels may never show a direct conversion at all, but without them, your search volume declines over time because fewer people know you exist. I’ve covered this in more depth in Google Ads vs Meta Ads, but the core point is that these platforms do fundamentally different jobs. Funding them equally ignores that reality.
An equal split ignores all of this. It gives the same resources to demand capture as it does to demand creation, regardless of where your business actually needs the most help. That’s not a strategy. It’s a spreadsheet exercise.
Frameworks That Actually Help
There are a few allocation models worth understanding, not as rigid rules but as starting points you adapt to your situation.
The 70-20-10 model puts 70% into your proven, primary channel, 20% into a secondary channel that’s showing promise, and 10% into genuine experimentation. This works well for businesses that have one channel clearly outperforming and want to expand without destabilising what’s working. The risk is that it can become a comfort blanket, keeping you anchored to the primary channel long after the economics have shifted.
The funnel-based model allocates by stage rather than by channel. You decide what proportion of budget should target awareness, consideration, and conversion, then assign channels to those stages. A common starting point is roughly 40% awareness, 35% consideration, and 25% conversion. This is more strategically sound because it forces you to think about what each pound is supposed to achieve rather than which platform gets it.
The marginal return model is the most sophisticated and the most accurate, but it requires data most businesses don’t have yet. The principle is straightforward: keep investing in a channel until the cost of the next conversion exceeds your target, then shift spend to wherever the marginal return is highest. Measured’s work on diminishing return curves explains this well. Every channel has a point where additional spend stops producing proportional results. Optimal allocation means equalising the marginal return across all channels, not the average return.
The distinction between average and marginal return trips up a lot of businesses. A channel might show brilliant average ROI because the first portion of spend performed incredibly well. But if the last portion you added was barely breaking even, the channel is already saturating. Your PPC reports won’t tell you this unless you’re specifically looking for it.
How to Decide Which Channels to Fund
Start with your customer, not your channel list. Map the journey from “never heard of you” to “signed the contract” and identify where the biggest gaps are.
If you’re generating plenty of awareness but struggling to convert, your budget should weight toward mid and lower-funnel channels: search, retargeting, and direct response. If conversions are efficient but volume is flat, you’ve got a demand generation problem and need to invest upstream in social, video, or display.
This is where a genuine multi-channel PPC strategy becomes essential. It’s not about being on every platform. It’s about understanding what each platform does in the context of your specific customer journey and funding accordingly.
A few practical filters for choosing channels:
Where is your audience? If you’re selling B2B software, LinkedIn might justify a larger share despite higher CPCs because the audience quality is dramatically better. If you’re selling consumer products, Meta and Google Shopping probably deserve the bulk of your investment.
What’s your sales cycle? Longer cycles with multiple stakeholders need more touchpoints across more channels. Shorter, impulse-driven purchases can concentrate on fewer platforms with stronger direct response.
What data do you already have? If you’ve been running one channel successfully, you have conversion data, audience insights, and creative learnings you can port to adjacent platforms. Expanding from Google to Microsoft Ads is a smaller leap than expanding from Google to TikTok. Sequence your expansion by proximity.
When to Scale and When to Pull Back
Scaling a channel is not the same as increasing its budget. Scaling means the channel can absorb more spend while maintaining acceptable efficiency. If you double the budget and the cost per acquisition stays within target, the channel is scaling. If the cost per acquisition climbs disproportionately, you’re hitting diminishing returns.
The signal to scale is consistent performance at current spend with evidence that you haven’t exhausted the available audience. More keywords to target, more audience segments to test, more creative variations to run. If all of those levers still have room, increase spend gradually (10-20% at a time) and monitor whether efficiency holds.
The signal to pull back is rising cost per acquisition without corresponding improvements in volume or quality. This usually means one of three things: you’ve saturated the audience at current targeting, your creative has fatigued, or the competitive landscape has shifted. Before cutting budget, diagnose which one it is. Creative fatigue and targeting exhaustion are fixable. Market shifts might require a genuine reallocation.
The hardest decision is pulling budget from a channel that’s “working” to fund one that hasn’t proved itself yet. This is where attribution matters enormously. If your attribution model is only measuring last-click conversions, you’ll systematically undervalue awareness channels and overvalue conversion channels. You’ll keep feeding the bottom of the funnel while the top slowly dries up.
The Mistakes That Cost the Most
Reacting to short-term data. A bad week on one platform doesn’t mean the channel is failing. Algorithms fluctuate. Auctions shift. Seasonality hits. Budget reallocation decisions should be based on sustained trends over weeks or months, not daily dashboards. The businesses that stop burning their marketing budget are the ones that resist the urge to panic-reallocate every time a metric dips.
Confusing channel performance with channel potential. A channel that’s been underfunded for six months will obviously show worse results than your primary platform. That doesn’t mean the channel doesn’t work. It means you’ve never given it enough resources to prove itself. Before writing off a channel, ask whether it ever had a fair trial.
Ignoring cross-channel effects. Cutting your Meta awareness campaigns might not show an immediate impact. But two months later, when your branded search volume drops because fewer people recognise your name, the connection becomes painfully clear. Channels don’t operate in isolation. Your budget allocation shouldn’t treat them as if they do. This is exactly why cross-channel reporting matters so much: if you can’t see how channels interact, you’ll make budget decisions that look rational in isolation but damage the system.
Optimising every channel for the same metric. If you measure display campaigns on direct conversions, they’ll always look worse than search. That’s not because display doesn’t work. It’s because you’re measuring a fish on its ability to climb a tree. Awareness channels should be measured on reach, frequency, and the downstream effects they have on other channels. Conversion channels should be measured on efficiency and volume.
Getting Started
If your current budget split was arrived at through guesswork or historical accident, here’s how to reset it.
First, audit what each channel is actually achieving. Not just conversions, but its role in the broader journey. Is it generating new demand, nurturing existing interest, or capturing ready-to-buy prospects?
Second, check whether every channel is above its minimum viable spend. If any channel is below the threshold where the algorithm can optimise, either increase its allocation or shut it down entirely. Thin spend helps nobody.
Third, choose a framework (funnel-based is usually the best starting point for most businesses) and map your current allocation against it. Where are you over-indexed? Where are the gaps?
Fourth, commit to reviewing quarterly, not weekly. Budget allocation is a strategic decision, not a tactical one. Give changes time to show their effect before adjusting again. And if your agency is only running one platform, they’re probably not the right people to advise on allocation across channels. I’ve written about why your PPC agency should be running more than Google Ads and the structural limitations that come with single-platform specialists.
The businesses that get budget allocation right aren’t the ones with the biggest budgets. They’re the ones who treat every pound as a strategic decision rather than a line item to be divided equally.
