The formula for marketing ROI isn’t complicated. The hard part is having the right numbers to put into it.
I’ve been in enough client meetings where marketing ROI was debated with incomplete data to know that the calculation itself isn’t the problem. The problem is that most businesses don’t track what they need to track to do it accurately.
Here’s the honest approach.
What Is the Basic Marketing ROI Formula?
Marketing ROI = (Revenue Attributed to Marketing − Marketing Cost) ÷ Marketing Cost × 100
If you spent $10,000 on marketing and can attribute $40,000 in revenue to that marketing, your ROI is:
($40,000 − $10,000) ÷ $10,000 × 100 = 300% ROI
That’s $3 back for every $1 spent. Or a 4x return on marketing spend.
Why Is Marketing ROI Hard to Calculate Accurately?
Two problems:
Attribution. Which revenue was actually caused by marketing? A customer might have found you through Google Ads, visited your website twice, seen your retargeting ad on another site, and then called after getting a referral from a friend. Which touchpoint gets credit for the revenue?
Time lag. Marketing investments made today don’t produce revenue today. If you spent $10,000 in March and closed $40,000 in clients in May, the ROI should connect those periods — but they’re usually reported separately.
The Practical Method for Small Businesses
For most businesses without enterprise attribution software, here’s the practical approach:
Step 1: Define your measurement window. I use 90-120 days. Marketing activity in this period, revenue closed in this period (recognizing some lag is expected).
Step 2: Define your marketing cost. Include everything: ad spend, agency fees, software costs, any internal time you can reasonably estimate.
Step 3: Count only clearly attributable revenue. Revenue from customers who explicitly came through paid advertising, tracked referral sources, or other clearly attributable channels. Leave out revenue where you can’t trace the source.
Step 4: Run the formula. Attributable revenue minus marketing cost, divided by marketing cost.
Step 5: Add pipeline. Don’t only count closed revenue. Include leads still in your pipeline, apply your historical close rate, and add the projected closed revenue. This gives you a fuller picture, especially for long sales cycles.
What Marketing ROI Should You Target?
This varies dramatically by industry and business model, but some rough guidelines:
Under 100% ROI (less than 2x): You’re spending more than you’re making from marketing after accounting for the cost. Not necessarily bad if you’re in early customer acquisition mode and LTV is high — but not sustainable long-term.
100-300% ROI (2-4x): Healthy for most businesses. Marketing is producing meaningful growth at a sustainable cost.
300%+ ROI (4x+): Excellent. Usually indicates either very efficient marketing or conservative attribution. If this is real, invest more.
What’s the Difference Between Marketing ROI and ROAS?
ROAS (Return on Ad Spend) only includes ad spend in the denominator. Marketing ROI includes all marketing costs.
A campaign with a 5x ROAS might have a 2x marketing ROI once you include agency fees, software, and other costs. Both metrics are useful — just know which one you’re looking at and what it does and doesn’t include.