Measuring loyalty: 7 metrics that actually matter
Measuring a loyalty program doesn't mean building twenty dashboards. For a small shop, seven metrics are enough to know if your stamp card works, where it breaks, and what it brings in euros. Here are all seven, each with a formula and a worked example.
Why you should measure your loyalty program at all
Many shops launch a stamp card and judge it by gut feel: "Seems to be going okay, people take them." The problem: gut feel doesn't catch a slow decline or a card that gets taken but never filled.
With a few numbers, you see right away whether the reward is too far away, whether customers drop out after the third stamp, or whether your Tuesday promotion actually brings guests. The foundation is a digital card where every stamp links to a person. Most of this doesn't work with paper.
The 7 metrics at a glance
| No. | Metric | Question it answers |
|---|---|---|
| 1 | Enrollment rate | How many customers sign up at all? |
| 2 | Active customers | How many are actually using the card now? |
| 3 | Retention rate | How many stay month to month? |
| 4 | Visit frequency | How often does an active customer come? |
| 5 | Redemption rate | How many cards fill up and get redeemed? |
| 6 | Reactivation rate | How many lapsed customers do you win back? |
| 7 | Incremental revenue | What does the program bring in euros? |
1. Enrollment rate
Formula: New cards in period ÷ customers in period × 100.
Example: Your bakery serves roughly 1,200 different customers a month (estimated from receipts). 180 of them loaded a card into Wallet that month. Enrollment rate: 180 ÷ 1,200 = 15 percent.
If the rate is low, it's almost never the reward—it's visibility. Where's the QR code, does your team mention it, is the sign readable? Tips are in the article QR code signage at checkout.
2. Active customers
An active customer got at least one stamp in a set period. Choose the period to fit your business: 30 days for cafés and quick service, 90 days for barbers and salons.
Example: 450 cards were issued total, 260 of them had a scan in the last 30 days. Active customers: 260. The other 190 aren't lost, but they're candidates for a win-back campaign.
This number is also the baseline for most other metrics and for provider pricing tiers. stampa, for example, charges by active customers, not cards ever issued.
3. Retention rate
Formula: (Active customers at end − new customers in period) ÷ active customers at start × 100.
Example: 240 active customers at month start, 50 new cards in the month, 260 at the end. Calculation: (260 − 50) ÷ 240 = 0.875, or 87.5 percent. Full derivation and targets are in Calculate your retention rate.
4. Visit frequency
Formula: Stamps in period ÷ active customers.
Example: 260 active customers collected 1,040 stamps in the month. Visit frequency: 1,040 ÷ 260 = 4 visits per month.
This is the metric a loyalty program should move directly. If frequency rises from 4 to 4.5, that's 130 extra visits across 260 customers in a month. At €5 per transaction, that's €650 in extra revenue without a single new customer.
5. Redemption rate
Formula: Redeemed rewards ÷ cards issued × 100 (over a longer period, roughly a quarter).
Example: Of 450 cards issued, 95 filled up and were redeemed in the quarter. Redemption rate: 95 ÷ 450 = 21 percent.
A very low redemption rate doesn't mean you save money. It means the reward feels unreachable and the card loses its power. A good indicator is where customers drop out: if many cards sit at 3 of 10 stamps, the card is too long. More in How many stamps until reward?.
6. Reactivation rate
Formula: Returning inactive customers ÷ inactive customers contacted × 100.
Example: 80 customers hadn't visited in 14 days and got a reminder on their phone. 18 came back within a week. Reactivation rate: 18 ÷ 80 = 22.5 percent.
This shows how well your win-back messages work. Test different texts and offers, compare the rate. A free extra often works better than a percentage discount because it's more concrete.
7. Incremental revenue (the real answer)
All the metrics above are intermediate values. The question an owner really asks is: does the program bring in more than it costs?
You can only measure this honestly with a control group. A small, randomly chosen portion of customers (say, every tenth) gets no promotions or reminders. The rest do. Then you compare visits between the two groups.
Formula: (Visits per customer with promotions − visits per customer without) × number of customers with promotions × average transaction value.
Example: Customers with promotions visit 4.4 times a month, the control group 4.0 times. Difference: 0.4 visits. With 234 customers in the promotion group and €6 average transaction: 0.4 × 234 × €6 = roughly €560 extra revenue per month.
Be honest with small numbers. With 30 customers, a 0.4-visit difference is noise. stampa uses this exact control-group method and only shows the value if it's statistically solid. Otherwise the dashboard says so openly instead of presenting a fantasy number.
How to track the numbers in practice
- Digital, not paper: Every scan ties to a card, you don't count anything. The dashboard shows active customers, stamps, returners, and redemptions live.
- Once a month, same day: Enter the seven values in a table. After three months you see trends.
- One change per month: If you change the reward, stamp count, and messages all at once, you'll never know what worked.
- Export for your accountant or yourself: A CSV export of customer data helps with deeper analysis.
Summary
Measuring a loyalty program with seven metrics isn't a project—it's fifteen minutes a month. Enrollment, active customers, retention, frequency, redemption, reactivation, and incremental revenue tell the whole story together. With a digital stamp card you get the values automatically, including an honest control group. With stampa you can try it free, up to 100 active customers and no credit card.