ROI stands for return on investment: the ratio of the net gain from an investment to the cost of that investment, expressed as a percentage. Spend 100,000 TRY and earn 130,000 TRY of net gain in return, and your ROI is 30%. The formula is simple; the hard part is what goes into the "net gain" and "cost" columns. That is also why ROI gets confused with ROAS in marketing: ROAS measures ad revenue, ROI measures the profit left after every cost is deducted.
The ROI Formula
A small example. A store buys a new packaging machine for 60,000 TRY. The machine saves 25,000 TRY of labour and 5,000 TRY of packaging waste a year; maintenance costs 4,000 TRY. Annual net gain is 26,000 TRY. ROI comes out at (26,000 − 60,000) ÷ 60,000 = minus 57%. That does not mean the investment is bad; it means it did not pay for itself in the first year. By the end of the second year total net gain is 52,000 TRY and ROI is minus 13%; in the third year it reaches 30%. Without saying which period you calculated ROI for, the result has no meaning.
How to Calculate ROI in Marketing
The same formula applies to advertising, but filling the columns takes more care. Say you spent 50,000 TRY on Google Ads and Meta over a month, and sales attributed to the ads came to 200,000 TRY. ROAS is 4; sounds good. For ROI you first have to deduct product cost from that 200,000. If the average gross margin on the products is 45%, gross profit on the sales is 90,000 TRY. From that, deduct ad spend (50,000), the cost of the agency or team managing the ads (say 10,000) and the loss from returns (8% of sales, roughly 7,000 TRY of lost margin): net gain is 23,000 TRY. Total investment is 60,000 TRY. ROI is 38%.
| Item | Amount |
|---|---|
| Sales attributed to ads | 200,000 TRY |
| Gross profit (45% margin) | 90,000 TRY |
| Ad spend | −50,000 TRY |
| Management cost | −10,000 TRY |
| Margin lost to returns | −7,000 TRY |
| Net gain | 23,000 TRY |
| ROI | 23,000 ÷ 60,000 = 38% |
For the same campaign, a ROAS of 4 and an ROI of 38% are both true at once. A store with a 25% margin running the same numbers would see net gain fall below zero: you can lose money at a ROAS of 4. ROAS showing green in the ad panel does not mean profitability.
The Difference Between ROI and ROAS
ROAS
Ad revenue divided by ad spend. Only the revenue the ad panel sees and only the media cost. Suitable for comparing campaigns, not for profitability. Read as a multiple: a ROAS of 4 means 4 TRY of revenue per 1 TRY.
ROI
Net gain divided by total cost. Product cost, returns, team and tool expenses included. Suitable for business decisions, too broad for campaign tuning. Read as a percentage: 38% ROI means 38 kuruş of net profit per 1 TRY.
The two have to be used together. Which campaign gets more budget is decided with ROAS; whether that campaign's budget writes a profit for the business is decided with ROI. If the ad team's ROAS is rising while the company's profit is falling, you have most likely drifted towards products with high ROAS but low margin. We explained how to read ROAS in a separate post; ROI, the subject of this one, starts where that post leaves off.
Three Traps of Marketing ROI
Attribution. The "sales attributed to ads" figure changes depending on which tool calculated it. Google Ads credits itself with the sale after its own click, Meta with the sale after its own view; the same order can appear in both panels. Calculating ROI on the total marketing budget rather than by channel largely removes this problem; if you need to go down to channels, use the sales GA4 distributes under a single attribution model.
Time. An ad's effect does not end in the same month. A customer won this month orders again next month; calculating ROI in a one-month window makes the investment look worse than it is, especially in categories with a high repeat-purchase rate. For a view that accounts for the customer's lifetime, you need the concepts of lifetime value and customer acquisition cost.
Hidden costs. Agency fees, creative production, tool subscriptions, the extra customer service load a campaign brings. When these are left out, marketing ROI always comes out higher than it really is. Adding every item is not essential; writing down which ones you left out is.
Payback Period: ROI's Companion
ROI answers "how much", not "when". Payback period tells you the moment an investment pays for itself: about 2.3 years in the machine example. In marketing, it is when the amount paid to win a customer comes back through that customer's orders. For businesses with tight cash flow, payback period is more decisive than ROI; an investment promising 80% ROI but paying back after 18 months ties up the cash for 18 months.
The Limit of Calculating ROI by Channel
The question "what is Google Ads' ROI and what is Meta's" is natural, but the answer is unreliable when calculated with each panel's own attribution data; the same sale is credited to both sides and the total exceeds real revenue. If a channel comparison is needed, one of two routes is chosen. The first is to use the sales GA4 distributes under a single attribution model; the second is to pause one channel for a specific period or region and measure the change in total sales. The second takes more effort, but only it shows which channel genuinely produces additional sales. For the monthly budget decision, total marketing ROI is enough; for the channel decision, one of these two methods.
What Data Do You Need to Track ROI?
- Ad spend: from every channel, for the same period
- Real orders and revenue: from the store platform, not the ad panel
- Gross margin by product: by the product mix actually sold, not an average
- Return rate and return cost
- Marketing team, agency and tool expenses
- Repeat purchase rate: to widen the ROI window
Half of this data lives in the ad panels, half in the store platform and the accounts. AdsLuma combines ad spend with real order and return data from ikas or Shopify on the same screen; once product cost is entered, ad profitability appears next to ROAS and the question "did this campaign actually make a profit" is answered without leaving the panel.
Frequently Asked Questions About ROI
What does ROI mean?
Return on investment. It shows, as a percentage, how much net gain an investment produced relative to its cost: (net gain − cost) ÷ cost × 100.
What is a good ROI?
It varies by industry, risk and period; there is no universal threshold. It should be higher than the return you would get by putting the same money elsewhere. Higher ROI is expected from high-risk and short-term investments.
Are ROI and ROAS the same thing?
No. ROAS divides ad revenue by ad spend and is read as a multiple; ROI divides net gain by total cost and is read as a percentage. A campaign with a ROAS of 4 can have an ROI of 38% or a negative one, depending on margin.
What does negative ROI mean?
That the investment has not yet paid for itself. Negative ROI in the first period is normal for long-term investments; what matters is that the payback period fits the business's cash strength.
AdsLuma combines ad spend with real order, return and margin data; ask Luma AI which campaign actually made a profit.
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