How to Measure KOL ROI: ER, CPE, EMV and ROAS (Hong Kong Benchmarks)
Measure KOL ROI with four metrics: engagement rate (ER), cost per engagement (CPE), EMV and ROAS. Formulas, HK$ examples, UTM and code setup, HK benchmarks.
Measuring KOL ROI comes down to four metrics: engagement rate (ER) = engagements ÷ followers; cost per engagement (CPE) = KOL fee ÷ engagements; earned media value (EMV) = the value of the exposure at ad prices; and ROAS = sales generated ÷ KOL fee. To count sales, set up UTM links or unique discount codes in advance.
Updated October 2026 · reviewed every quarter.
The four metrics and their formulas
| Metric | Formula | What it tells you |
|---|---|---|
| ER (engagement rate) | (likes + comments + shares + saves) ÷ followers × 100% | How engaged the audience is |
| CPE (cost per engagement) | KOL fee ÷ engagements | What each engagement costs |
| EMV (earned media value) | Impressions ÷ 1,000 × ad CPM | How much advertising it's worth |
| ROAS (return on ad spend) | Sales generated ÷ KOL fee | How much in sales each HK$1 brings |
| ROI (return on investment) | (Gross profit − cost) ÷ cost × 100% | Whether you made money after costs |
ER can also be calculated as engagements ÷ reach, which gives a higher figure. When you compare KOLs, use the same method for all of them.
A worked example in HK$
A micro KOL with 25,000 followers charges HK$8,000 for 1 Reel and 3 Stories.
Data 7 days after posting (example):
| Data | Value |
|---|---|
| Impressions | 30,000 |
| Engagements | 1,000 |
| Link clicks | 400 |
| Discount code uses | 32 orders |
| Average order value | HK$450 |
| Gross margin | 60% |
The calculation:
- ER = 1,000 ÷ 25,000 = 4%
- CPE = 8,000 ÷ 1,000 = HK$8
- EMV (assuming your ad CPM is HK$X) = 30 × X
- Sales = 32 × 450 = HK$14,400
- ROAS = 14,400 ÷ 8,000 = 1.8
- ROI = (14,400 × 60% − 8,000) ÷ 8,000 = (8,640 − 8,000) ÷ 8,000 = 8%
A ROAS of 1.8 looks good, but after costs the ROI is only 8%. That's why you need to look at ROAS and ROI together.
Setting up UTM links and discount codes
UTM links
Give each KOL their own link and track them separately in Google Analytics:
https://yourwebsite.com/product?utm_source=instagram&utm_medium=kol&utm_campaign=2026q4_launch&utm_content=kolname
| Parameter | What to put |
|---|---|
| utm_source | The platform, e.g. instagram, threads, xiaohongshu |
| utm_medium | Always kol |
| utm_campaign | The campaign name |
| utm_content | The KOL's name, to tell each KOL apart |
Share it as a short link or with the Stories link sticker. Links in Instagram post captions aren't clickable, so put them in the bio or in Stories.
Unique discount codes
- One code per KOL, e.g.
MANDY15. - Codes work in physical shops too, which suits food and drink and retail.
- Codes get passed around on deal sites, so the numbers may be overstated.
Benchmarks
| Metric | Hong Kong benchmark |
|---|---|
| ER: nano and KOC (under 10K followers) | About 5–15% |
| ER: micro (10K–50K followers) | About 3–8% |
| ER: mid-tier (50K–200K followers) | About 2–4% |
| ER: 200K+ followers | About 1–2% |
| CPE | About HK$2–10 |
| ROAS | About 1.5–4 |
Agencies calculate EMV in different ways, so their figures can't be compared with each other. The best benchmark is the numbers from your own past campaigns.
When to report
| When | What to collect |
|---|---|
| 24 hours after posting | Early engagement, to judge whether the post is worth boosting with ads |
| 7 days after posting | Reach, engagement and clicks (most of the data has settled by then) |
| 30 days after posting | Discount code and UTM sales |
The data should ideally come from the platform's dashboard or official API, not only from figures the KOL compiles. For how to check, see how to spot fake followers.
FAQ
How do you calculate KOL ROI?
ROI = (gross profit from the KOL − KOL fee) ÷ KOL fee × 100%. To count sales, set up UTM links or unique discount codes in advance.
How do you calculate a KOL's engagement rate?
(Likes + comments + shares + saves) ÷ followers × 100%. For example, 20,000 followers and an average of 600 engagements gives an engagement rate of 3%.
What is CPE?
Cost per engagement: the KOL fee ÷ the number of engagements. HK$8,000 for 1,000 engagements is a CPE of HK$8.
What is EMV?
Earned media value: the value of a KOL's exposure, calculated at ad prices. There's no industry-standard method, so we recommend calculating it with your own ad CPM.
What's the difference between ROAS and ROI?
ROAS is sales ÷ fee, with no costs deducted; ROI is the return after product costs. A ROAS above 1 doesn't mean you made money.
When should you measure KOL results?
Look at reach and engagement 7 days after posting, and at sales after 30 days.
Back to the 2026 Hong Kong KOL agency guide.