Google Ads ROI Calculator

How to calculate Google Ads ROI

Return on investment is the profit your ads make you compared to everything it costs to run them. The formula is simple:

ROI = (Revenue minus Cost) ÷ Cost × 100

The cheap version treats media as the only outlay, which is how a campaign looks great on a slide and loses money in the bank. The honest version subtracts your cost of goods and agency fees first, so you measure what you actually keep:

True profit = (Gross profit minus total spend) ÷ total spend × 100

The one figure that takes any work is revenue, and that is just a funnel, each step feeding the next:

Monthly ad spend ÷ CPC = Clicks → × Conversion rate = Leads → × Close rate = Customers → × Value = Revenue

The numbers you need (and where to get them)

• Your model = E-commerce, SaaS, or Services/Leads. This relabels the fields to match how you earn, whether that is orders, free trials, or deals.
• Monthly ad spend = what you plan to put behind your Google Ads campaigns each month, before agency fees. This is your Google Ads budget for media.
• Average cost per click (CPC) = the average price you pay for each click on your ads. Pull it from your Google Ads account, or estimate it in Keyword Planner if your campaigns aren’t live yet.
• Conversion rate = the percentage of clicks that take the money action: a purchase, a free trial, or a form fill on your website.
• Close rate = for SaaS and services, how many leads turn into paying customers. E-commerce skips it, since the purchase is the conversion.
• Average customer value = your average order value in e-commerce, or your lifetime value where purchases recur. It’s the average revenue you make per customer.
• Gross profit margin = the percentage left once COGS is removed. It’s what separates a partial ROI (like ROAS) from your real ROI (what actually lands in your bank account).
• Management fees and other costs = your management fees (agency or in-house), your tools, and your production costs (video, ads, creative, etc.). Often forgotten, even though they weigh just as much.

What you get back

• Net profit per month = the profit you actually take home from your Google Ads. It’s the first number your CFO will look at.
• Your true return on investment (ROI) as a percentage.
• ROAS (return on ad spend) = your total revenue divided by your ad spend. It’s a partial ROI that ignores every cost beyond your media budget.
• Your funnel = clicks, leads, total customers, and revenue, so you see where money is made or lost.
• Cost per lead and cost per acquisition, all-in.
• Your maximum bid and breakeven, the ceilings covered next.

A worked example

Here is the estimate for a store that puts $3,000 a month behind its Google Ads campaigns at a $1.20 click price, converts 4% of clicks into purchases, on a $120 average order, a 45% margin, and $500 in total fees (management, production, etc.):

• $3,000 ÷ $1.20 = 2,500 clicks
• 2,500 × 4% = 100 orders from new customers, for $12,000 in total revenue
• $12,000 × 45% = $5,400 gross profit
• Total spend = $3,000 media + $500 fee = $3,500
• You keep $1,900 a month, a 54% return and a 4.0x ROAS

SaaS and lead-gen companies run the same chain but add a close rate and swap order value for deal or lifetime value, which the model toggle handles for you.

The most you can afford to bid

This is the step most calculators skip, and the one that decides whether a campaign is profitable or burns cash like there’s no tomorrow. Instead of only showing your profit, this calculator helps you find the most you can pay per click (or per conversion: lead, purchase) without losing money, so you never push your Google Ads further than your bank account can handle.

Max profitable CPA = Customer value × Gross margin
Max profitable CPC = Max profitable CPA × Conversion rate
Breakeven ROAS = 1 ÷ Gross margin

In the example, each customer is worth $54 in gross profit, so at a 4% conversion the most you can afford to pay per click is around $2.16. You’re bidding $1.20, which leaves room to go after more clicks, even pricier ones. Cross $2.16 and the same campaign starts losing money on every click (unless your conversion rate is higher). ROAS works the same way: at a 45% margin you need a ROAS of about 2.2 just to cover your costs, so anything above that is extra profit for you. You can get a similar number using my breakeven ROAS calculator.

True profit vs vanity ROAS

A 4x return on ad spend looks perfectly optimized, until you realize your media budget isn’t your only expense. On a 30% margin that 4x is only 1.2x in gross margin, and a 20% fee finishes it off. This tool leads with profit over revenue, because it’s the only number that passes your CFO’s test: an ROI calculated only on your ad budget raises questions; what you actually keep answers them straight.

What a good return looks like

There’s no magic number, because your result depends on your margin, your industry, and your customer value far more than any average. A ROAS of 3 to 5 is the target you’ll usually hear, even though on its own it means nothing: a 4x is solid on a 70% margin and a loss on a 20% one. Plenty of owners stay skeptical of paid search precisely because they judge their advertising on a generic average instead of calculating their own breakeven. Once you’ve calculated your real ROI, use the scale below to read it:

Benchmarks by business model

No numbers of your own yet? These industry benchmarks give you a starting point. Swap them for your real data the moment you have it, because your real figures always win out over the best benchmarks. The ranges match the three business types, and they vary with your market (geographic targeting) and your sector/vertical.

Cost per click swings hardest by vertical: legal and insurance keywords run $50 to $200+, home services land around $5 to $25, and the same keyword runs far higher in a major metro. A landing page conversion rate below the 3% to 5% norm (considered the standard) is often an easy quick win that can move your ROI significantly. These industry benchmarks move, so treat every figure as a starting point and trust your own data.

Why your real return may differ

This tool will show you a great number if you feed it optimistic assumptions, but your estimate is only worth what your numbers are worth: if your numbers are close to reality, your estimate will be far more accurate than if they’re too optimistic or disconnected from your reality. In real life, a Google Ads account is always moving: auction competition, seasonality, your match types, and your landing pages all shift your results. So use your real numbers as soon as you have them, question your assumptions, and redo the calculation whenever your data changes over time.

There’s another trap to watch for. Google doesn’t have the full picture; it only looks at what happens on its own turf: the moment a sale passes through one of your Google campaigns, it claims all the credit, even when other channels did a good part of the work. So the ROI it shows you is overstated, especially since it ignores your refund requests and your real margins. Your real ROI is in your CRM: that’s where you see what you actually sell and what you keep, not just the number of clicks you paid for and the number of leads you generated. The ideal move is to send your real sales back to Google (your offline conversions): that way, it stops optimizing for form submissions and starts going after real customers for you.

That’s where a Google Ads consultant comes in. Book a free Google Ads strategy call with me , and we’ll pressure-test these numbers against your real data, your real margins, and build a plan to hit your goals.