How to find duplicate customers in Shopify

Finding duplicate customers is a counting job before it is a merging job. Shopify gives you the tools to look up a profile and to export your list. This playbook turns them into a method you can repeat, and ends with a number you can trust: how many surplus profiles your store holds.

Does Shopify find and merge duplicates automatically?

No. The Shopify Help pages we read describe a merge that you start yourself. You open one profile, choose More actions and Merge customer, search for the second profile, review the Merged customer section and confirm. The search accepts a first name, last name, email address, phone number or credit card number, which helps when you already know which customer to look for.

Those pages describe no automatic duplicate finder and no automatic merging. That holds for the merge page and the managing customers page as we read them on October 26, 2026, and for nothing else. Customer segments are saved ShopifyQL queries, and the segments page we read does not mention a filter for duplicates.

Shopify merges two profiles at a time, and says “To merge more than 2 customers together, repeat the procedure for each additional profile.” After a merge, “you can’t reverse the process”, so the finding and the deciding are yours.

We also found no public study that measures how common duplicate customers are on Shopify stores, so this playbook gives you a way to measure yours.

The signals, strongest to weakest

Rank the details that profiles share. The stronger the signal, the less review a group needs.

The first two rows are the strongest evidence. The last two rows are reasons to look at a pair, and they prove little alone. Same address, same person, or family? shows how to tell them apart.

Export and group

Shopify lets you export a CSV of your customers and their details. Open it in a spreadsheet and work through these passes:

1. Put phone numbers in one format by removing spaces, dashes and brackets.
2. Lower-case every email and trim stray spaces.
3. Sort by phone number and mark rows that share one.
4. Sort by email and mark rows whose emails look like the same address with a typo.
5. Sort by address and name, and mark rows that share both.

Shopify’s customer list shows at most 50 customers per page, so a spreadsheet is faster for a large list.

Count your own duplicates

Once you have groups, three numbers give you the size of the problem:

• People: the number of real people behind the profiles you reviewed.
• Profiles: the number of profiles you reviewed.
• Surplus profiles: profiles minus people.

This formula is our own reasoning, not a figure from Shopify. For example: A made-up export of 500 profiles that groups into 460 people has 500 − 460 = 40 surplus profiles. Worked example (made up) Repeat the same count later and compare, so you can see whether the surplus is growing.

A count of duplicate groups is a different unit from surplus profiles. A group of three profiles is one group and two surplus profiles.

Decide group by group

For each group, choose one of three outcomes: one person, family, or unsure. Merge only the first kind. Shopify says that after profiles are merged, “you can’t reverse the process”, so keep unsure groups apart until you have more evidence.

Before any merge, work through the safe merge checklist. It covers the details to keep, marketing subscriptions and the nine cases Shopify refuses to merge.

Check again on a schedule

Shoppers keep using second emails, so duplicates keep forming. Repeat the count after a large import, a sale or a change to your checkout. A short monthly review catches new groups while they are small. For the ways duplicates form, read why Shopify creates duplicate customers.