AUDIENCE: YOUR OLD CUSTOMER LIST IS AN AD AUDIENCE Upload the people who have already paid you to Meta as a customer list, build a lookalike audience from it, and keep them out of the ads meant for new customers. Every name, email and phone number below is an example. Menu names in quotes are Meta's, from its Business Help Center (read 29 September 2026). Check them against your own Ads Manager as you go. THE FOUR STEPS 1. Export your past customers from your invoicing tool or CRM: name, email, phone and ZIP code. Choose CSV. 2. Upload it in Ads Manager: "Audiences", "Create audience", "Custom audience", "Customer list". Meta hashes the list before it matches it. 3. Build a "Lookalike audience" from that list. A smaller audience size matches your list more closely; a larger one is broader. 4. In every ad set meant for new customers, exclude the customer list, so you don't pay to reach people who already buy. 1. THE COLUMNS Head each column exactly as written on the left. One customer per row. CSV or TXT file. Start with these five: [ ] email One email address per cell. Up to 3 email columns. Example: sam@example.com [ ] phone Country code on every number, even if everyone is in one country. In the US that means a 1 in front. Punctuation is fine either way. Up to 3 phone columns. Example: +13035550142 [ ] fn First name, in its own column. Split full names into fn and ln. Example: Sam [ ] ln Full last name, with or without accents. Example: Rivera [ ] zip Five digits. A hyphen and four more digits is allowed, not needed. Example: 80203 Add these if you have them: [ ] country Two-letter country code, in its own column, even if everyone is in the same country. Example: US [ ] ct Full name of the town or city. Example: Denver [ ] st Full state name, or the two-letter abbreviation for a US state. Example: CO [ ] value What each customer has spent with you, number only, no currency sign. Optional. Lets you build a value-based lookalike later. Example: 1250 What the file looks like (the first line is the headers; these three rows are examples): email,phone,fn,ln,zip,ct,st,country,value sam@example.com,+13035550142,Sam,Rivera,80203,Denver,CO,US,1250 dana@example.com,+13035550187,Dana,Brooks,80211,Denver,CO,US,480 luis@example.com,+17205550119,Luis,Moreno,80218,Denver,CO,US,2300 2. UPLOAD THE LIST (Ads Manager) You need to own an ad account connected to a business portfolio, or have admin or advertiser permission on one. A new ad account may have to wait a few weeks before it can create a customer list audience. [ ] Open "Audiences". Select "Create audience", then "Custom audience". [ ] Select "Customer list", then "Next". "Prepare list" shows Meta's formatting instructions. Select "Next". [ ] On "Add list", choose "Inclusions or exclusions". Not "Only exclusions": that audience can't be used to make a lookalike, and the choice can't be changed later. [ ] Choose "Upload a file" and pick your CSV. Give it an "Audience name" you'll recognise, such as "Past customers". If asked whether the file has a customer value column, say yes only if you added value. Accept the custom audience terms, then "Next". [ ] "Map identifiers": a check icon means a column is mapped and ready to be hashed. An exclamation point means a column needs fixing or was left out; fix it first. Then "Import and create". [ ] The audience shows "Populating", then "Ready". Use it once it reads "Ready". 3. BUILD THE LOOKALIKE [ ] In Audiences, select "Create audience", then "Lookalike audience". [ ] Pick your customer list as the source. [ ] "Select audience size" with the slider. Smaller percentages match your list more closely; larger ones are broader. The ad set's location is used; you don't pick one here. [ ] Select "Create audience". It can show "Populating" for up to 3 days. You can start running ads with it straight away; its size grows as it fills. Size of the source: Meta's formatting guide says a customer list should include at least 1,000 customers. A lookalike needs a source of at least 100 people, and Meta recommends 1,000 to 5,000. Meta also suggests building the source from your best customers rather than all of them, depending on your goals. The people in your list are left out of the lookalike automatically. 4. EXCLUDE YOUR CUSTOMERS (every ad set meant for new customers) Objective Sales, App promotion or Leads: [ ] In the ad set, "Audience", then "Show more controls". Add your customer list under "Custom audience exclusion". To add the lookalike: "Add suggestions (optional)", then pick it under "Custom audience inclusions". Objective Awareness, Traffic or Engagement: [ ] In the ad set, "Controls", then "Show more controls". Select "Exclude these custom audiences", then find your list with "Search existing audiences". To add the lookalike: "Audience", "Suggest an audience", "Show settings", "Include these custom audiences". An audience you include this way is a suggestion: Meta can also show the ad to other people when it expects better performance. To keep the ad set to the lookalike only, use "Further limit the reach of your ads" (or "Further limit your audience", then "Reach a limited audience") and untick "Use as a suggestion". The exclusion is not a suggestion: the people in your list are kept out. BEFORE YOU UPLOAD Leave out: - anyone who has opted out of their details being used to build ad audiences - anyone you know or should know is under 13 - Social Security numbers, passwords, card or bank details, and anything about someone's health, money or credit - anything in the audience's name that hints at any of the above Check: - You need a lawful basis to upload the list. Meta asks you to review its custom audience terms first. This checklist doesn't cover the law; settle that with your own adviser. - Meta hashes the list before matching: each value becomes randomized code that can't be reversed, and the hashed values are deleted after matching. - Lookalikes are limited or unavailable for some ads about financial products and services, employment or housing. KEEP IT CURRENT A customer list that hasn't been updated in over 30 days shows as "Outdated", which Meta says may affect delivery. Export again and use "Update list", so this month's new customers are excluded too. The "Match score" column in Audiences shows how well your list matched; more emails and phone numbers can raise it. MORE FROM META (Business Help Center) Formatting guidelines: https://www.facebook.com/business/help/2082575038703844 Prepare your data: https://www.facebook.com/business/help/606443329504150 Create a customer list: https://www.facebook.com/business/help/170456843145568 About hashing: https://www.facebook.com/business/help/112061095610075 Create a lookalike audience: https://www.facebook.com/business/help/465262276878947 About lookalike audiences: https://www.facebook.com/business/help/164749007013531 Use custom or lookalike audiences (includes the exclusion steps): https://www.facebook.com/business/help/572787736078838