How to calculate marketing ROI.

"Is our marketing working?" is the question every business owner asks, and most can't answer it with a number. They know what they spent. They have a rough idea of what came in. What they don't have is the one figure that says whether the money came back.

That figure is marketing ROI. This guide shows you how to calculate it properly, where most people get it wrong, and how to work it out for ads, SEO and your overall budget. To save you the spreadsheet, we've also built four free calculators in The Bleu Lab that do the maths in seconds.

What is marketing ROI?

Marketing ROI (return on investment) tells you how much profit your marketing produced for every dollar you put into it. It's the cleanest way to compare channels that otherwise look nothing alike: a Google Ads campaign, an SEO retainer, a trade show and an Instagram budget all go into the same formula.

The marketing ROI formula

Here's a worked example. You spend $2,000 on a campaign. It brings in $10,000 in sales. Your gross margin (what you keep after the cost of the product and delivery) is 40%.

1. Profit from marketing: $10,000 × 40% = $4,000
2. ROI: ($4,000 − $2,000) ÷ $2,000 = 1.0, or 100%

For every dollar you spent, you got your dollar back plus another dollar of profit.

The mistake almost everyone makes

Most people plug revenue into the formula instead of profit. Do that with the example above and you get ($10,000 − $2,000) ÷ $2,000 = 400%. It looks four times better than it is, and it's how businesses talk themselves into campaigns that quietly lose money. If you sell a product that costs you $60 to make and ship, a $100 sale isn't $100 of return. It's $40.

The second mistake is leaving costs out. Ad spend is only part of it. Count agency or freelancer fees, software, design and the content you paid for.

ROI vs ROAS: which one should you use?

ROAS is the number Google and Meta show you, and it's useful for comparing campaigns inside one ad account. But it can lie about profit. At a 20% margin, you need a 5x ROAS just to break even (break-even ROAS = 1 ÷ margin), so a 4x ROAS that looks healthy is actually losing you money.

Use ROAS to steer campaigns. Use ROI to decide whether a channel deserves more budget.

Run it yourself: the free ROAS & break-even ROAS calculator shows your ROAS, the ROAS your margin needs to break even, and your profit after ad spend.

How to calculate ROI for each channel

Google and Meta ads

Ads are the easiest channel to measure, as long as conversion tracking is set up properly in Google Ads, Meta and GA4.

1. Take the revenue the platform (or GA4) attributes to the campaign.
2. Multiply by your gross margin to get profit.
3. Subtract ad spend plus management fees.
4. Divide by total cost.

If you're planning a campaign rather than reviewing one, work backwards from the result you want. Fifty leads a month at a 5% landing-page conversion rate needs 1,000 clicks. At $3.50 a click, that's a $3,500 monthly budget, or about $115 a day.

Run it yourself: the Google Ads budget calculator does exactly that, then shows your cost per lead and projected ROAS before you spend a cent. If you'd rather hand the campaigns to specialists, see our Google Ads management service.

SEO

SEO is harder to measure because the return arrives slowly and keeps arriving after you stop paying. The forecast works like this:

1. Visits = monthly searches for your keywords × the click-through rate for your position. In Backlinko's analysis of around 4 million Google results, the #1 organic result got an average click-through rate of 27.6%, and was 10 times more likely to be clicked than the result in position 10.
2. Customers = visits × your website conversion rate.
3. Profit = customers × average sale value × gross margin.
4. ROI = (profit − monthly SEO cost) ÷ monthly SEO cost.

For a real-world example: one of our clients, a craft cannabinoid brand, grew monthly organic revenue from $11,344 to $47,503 in 18 months (case study). That revenue now arrives every month without paying for each click.

Run it yourself: the SEO ROI calculator estimates the visits, customers and revenue page one would bring you, and whether it pays back your SEO spend. For how long that usually takes, see how long SEO really takes, and for what we do for smaller businesses, see our small business SEO services.

Your overall marketing budget

Before you can measure return across channels, you need a sensible budget to measure against. The U.S. Small Business Administration's widely quoted guideline is 7 to 8% of gross revenue for businesses with sales under $5 million and net profit margins of 10 to 12%. Businesses holding steady can spend less; businesses launching or chasing growth often spend more.

Run it yourself: the marketing budget calculator turns your revenue and growth goal into a monthly budget, then splits it across ads, SEO, social, design and email.

The 4 free calculators in The Bleu Lab

We built these for planning our own clients' budgets, then made them free for everyone. No sign-up, no email gate, and the maths runs in your browser.

See all the free tools in The Bleu Lab →

Five ways to improve your marketing ROI

1. Fix tracking first. If conversions aren't tracked, every ROI number is a guess. Set up GA4 key events and ad-platform conversion tracking before you judge anything.
2. Cut what never converts. In paid search, the fastest win is usually adding negative keywords for searches that spend money and never lead to a sale.
3. Improve the landing page before buying more traffic. Doubling your conversion rate halves your cost per lead. It's usually cheaper than doubling traffic.
4. Give slow channels a fair window. Judge SEO over 6 to 12 months and ads over at least a few weeks of clean data. Pulling the plug early is how most SEO budgets get wasted.
5. Move budget toward the best ROI, not the biggest numbers. A channel with fewer, more profitable sales beats one with lots of low-margin ones.

Calculate it, then act on it

Marketing ROI is simple maths: profit in, cost out, divided by cost. The hard part is using honest inputs and giving each channel enough time to prove itself. Start with the free calculators, and if the numbers raise questions, book a free call and we'll walk through them with you.

Sources: Backlinko, "We Analyzed 4 Million Google Search Results. Here's What We Learned About Organic Click Through Rate" (27.6% average CTR for position 1; position 1 is 10x more likely to be clicked than position 10); U.S. Small Business Administration budget guideline as reported by Chron Small Business (7–8% of gross revenue for businesses under $5M in sales with 10–12% net margins). Client results are from Hello Bleu's published case studies.