Social media ROI mistakes: getting the sum wrong

Key takeaways

The common social media ROI mistakes are leaving staff and owner time out of the cost, counting revenue instead of profit, ignoring repeat customers and judging after a month. Return on investment (ROI) is profit from social media customers minus the full cost, divided by that cost. Get both halves right before deciding.

• ROI = (gross profit from social customers − full cost) ÷ full cost.
• Full cost includes time, tools, ad spend and fees.
• Use gross profit, not revenue.
• Include repeat purchases over a reasonable period.

What is social media ROI?

Social media ROI is the profit a business makes from customers won through social media, after subtracting the full cost of the social media activity, expressed as a ratio or percentage of that cost. A positive ROI means social media earned back more than it cost.

• The most common social media marketing mistakes small businesses make
• How to measure social media ROI for a small business

Which costs do businesses leave out?

Businesses often leave out time, which is usually the biggest cost. Four hours a week at about £16.27 an hour, the approximate employer cost of an employee on the April 2026 National Living Wage, is about £3,380 a year. Add tools, ad spend, agency fees and content costs such as photography.

• What social media mistakes really cost a small business

Why is revenue the wrong number?

Revenue is the wrong number because it ignores what it cost to deliver the sale. £10,000 of revenue at a 30% gross margin is £3,000 of profit. As an illustration: £3,000 of profit from social customers against £2,000 of full cost gives an ROI of 50%, not the 400% a revenue sum would suggest.

Should repeat customers count?

Yes, over a sensible period such as 12 months, because social media often wins customers who come back. Ignoring repeat value undersells social for businesses such as salons, restaurants and retailers. Be consistent about the period you use.

• Customer lifetime value: what a social customer is worth

When is ROI the wrong measure?

ROI is a poor measure in the first months, when audiences are still building, and for brand activity whose effect shows over longer periods. Use leading indicators early and judge ROI over at least a quarter.

How do you check your ROI sum?

Check it by listing every cost line and every revenue assumption. Ask whether hours are included, whether profit or revenue was used, which customers were counted and over what period. A sum that leaves out hours or uses revenue will look far better than the reality.

• Hours missing from costs.
• Revenue used instead of profit.
• Repeat purchases ignored.
• Results judged after one month.

What does this look like in practice?

A pattern we see: an ROI figure that looks excellent because it uses revenue and leaves out the owner's ten hours a week. Recalculating with profit and full cost gives a less flattering but more useful number, and shows where time can be cut.

• See client work
• Social Media Marketing for UK businesses

ROI checklist

• Include time, tools, ads and fees.
• Use gross profit, not revenue.
• Count repeat purchases over 12 months.
• Judge over at least a quarter.
• Use consistent tracking.

• Social media attribution mistakes: why last click undersells
• Social media legal mistakes UK businesses make

Next step

Work out last quarter's full social media cost, including hours. Then estimate profit from customers who came through social.