Meta vs. Google Ads Budget Allocation Simulator

This simulator takes your current Meta and Google Ads budgets, plugs in your real CPA numbers, and shows you exactly what happens to your total conversion volume when you shift 10, 20, or 30 percent of spend between channels. No spreadsheet required. Just a clear answer to the question every media buyer should be asking every month: where does my next dollar work hardest?

Meta vs. Google Budget Allocation Simulator

Channel Setup

Meta Ads

Monthly Budget (total spend)

Cost Per Acquisition (CPA)

Est. Monthly Conversions —

Google Ads

Monthly Budget (total spend)

Cost Per Acquisition (CPA)

Est. Monthly Conversions —

Simulation Settings

Budget Shift Scenarios

Assumes CPA stays constant within ±20% of current level. Results are directional estimates.

Shift Direction

💡

Next Dollar Analysis

Meta Ads

conversions per $100 spent

Google Ads

conversions per $100 spent

Budget Split by Scenario

Scenario Comparison

Scenario	Meta Budget	Google Budget	Meta Conv.	Google Conv.	Total Conv.	vs. Baseline

How the Budget Allocation Simulator Works

Enter four numbers: your current monthly budget and cost per acquisition (CPA) for Meta Ads, and the same for Google Ads. The tool immediately calculates your baseline conversion volume for each channel, then models what happens under six reallocation scenarios – shifting 10%, 20%, or 30% of your combined budget toward Meta or toward Google.

The simulator assumes your CPA remains stable at current levels (a reasonable approximation for moderate budget shifts). Results are directional, not a guarantee. But they’re grounded in your actual data, not industry averages.

Reading Your Results

The first thing you’ll see after running the simulation is a plain-English recommendation. If one channel converts significantly more efficiently than the other, the tool tells you.

This section answers the “marginal dollar” question directly. It shows how many conversions each channel produces per $100 of spend at current CPA levels. The channel with the higher bar is where incremental budget has the most immediate impact.

A stacked bar chart shows the Meta/Google budget ratio for every scenario. This makes it easy to communicate reallocation decisions to clients or stakeholders without having to explain a table of numbers.

The full table breaks down every scenario: Meta budget, Google budget, conversions per channel, total conversions, and the delta versus your current baseline. The best-performing scenario is highlighted in green; the worst in red.

Key Terms & Assumptions

CPA (Cost Per Acquisition): The average amount you spend to generate one conversion: a purchase, lead, sign-up, or other defined action. Pull this directly from your Meta Ads Manager or Google Ads account for the most accurate results.

Budget Shift: Expressed as a percentage of your total combined budget, not of one channel’s budget alone. A 10% shift on a $13,000 total budget moves $1,300, regardless of how that total is currently divided.

Baseline: Your current allocation, used as the reference point for all delta calculations. The simulator does not modify your baseline, but it only models alternative distributions.

Linear CPA Scaling: The simulator assumes that CPA remains constant as budget shifts. In practice, CPA tends to rise modestly at higher spend levels due to audience saturation and auction pressure. For shifts above 30%, treat results as optimistic estimates and validate with actual testing.

Situations Where This Tool Is Useful

Budget Reviews: You’re 30 days into the month, one channel is underperforming, and your client wants to know what to do with the remaining budget. So pull up the simulator, enter the month-to-date CPAs, and arrive at the reallocation conversation with actual numbers.

New Channel Testing: You’ve been running Meta for 18 months and you’re considering adding Google Ads (or vice versa). The simulator lets you model what the conversion impact would be if you funded the new channel by pulling from the existing one.

Budget Negotiations & Planning: When planning the next quarter, clients often ask “should we increase the budget or reallocate it?” This tool gives you a framework to answer that question with data. Run a few scenarios, export the results discussion, and come to the planning meeting with a clear point of view.

Diagnosing a Blended CPA Problem: If your overall cost per acquisition is creeping up and you can’t immediately tell why, this simulator quickly surfaces whether the issue is channel mix rather than performance.

FAQs

What data do I need to use this simulator?

You need four numbers from your ad accounts: your current monthly budget and your average CPA for both Meta Ads and Google Ads. Pull CPA from the last 30 days for the most accurate baseline. If you’re using a blended CPA that includes both prospecting and retargeting, that works fine. But stay consistent across both channels.

Does the simulator account for audience saturation or diminishing returns?

Not automatically. The tool uses linear CPA scaling, which means it assumes your cost per conversion stays flat as budget shifts. In reality, pushing significantly more spend into a single channel will often raise CPA as you exhaust high-intent audiences or drive up auction CPMs. For shifts of 10–20%, the linear model is a reasonable approximation. For larger shifts, treat the output as a best-case directional estimate.

What does “budget shift” mean?

It’s a percentage of your total combined budget. For example, if you’re spending $5,000 on Meta and $8,000 on Google ($13,000 combined), a 10% shift moves $1,300 between channels. This approach makes it easier to compare scenarios fairly, since a fixed percentage of one channel’s budget would produce asymmetric shifts.

My Meta CPA is lower, but my agency says to keep investing in Google. Why?

CPA efficiency is one input, not the whole picture. Google Search often captures demand that already exists as users are actively searching for what you sell. Meta creates demand further up the funnel (mid and top funnel). A lower Meta CPA today might not account for the full attribution cycle, or your Google campaigns may be capturing conversions that Meta’s prospecting helped generate. Use this tool to start the conversation, not end it.

Can I use this for channels other than Meta and Google?

The labels are specific to Meta and Google, but the underlying math – budget divided by CPA equals conversions – works for any two paid channels. If you want to compare, say, LinkedIn and Google, simply enter those numbers in the corresponding fields. The logic holds regardless of the platform names.