Gingerbread-man shapes cut from rolled cookie dough beside a metal cookie cutter and a rolling pin.

Lookalikes

How do I build a Meta lookalike audience from my closed-won B2B customers?

By The Tofu team ·

Upload the contacts on your closed-won deals as a customer list, then use it as the source of a lookalike. Meta needs at least 100 people in the source and recommends 1,000 to 5,000, and only matched people count, so include every contact at won accounts and every identifier you have. Add deal value as a customer value column to make it value-based. Ads Manager now takes the location from the ad set, and with Advantage+ audience on, the lookalike is a suggestion, not a limit.

As of October 2026.

Who should go in the seed list?

Your best customers, not everyone. Meta says you may get better results "if you use an audience made from your best customers rather than one that includes all your customers." For B2B, that means the people on closed-won deals: buyers, champions and active users at accounts that look like the ones you want more of. Leave out churned customers, closed-lost deals and early pipeline.

Pick a time window that matches your current ideal customer, so older wins don't teach Meta the wrong profile.

Name the audience plainly, such as "Closed-won contacts 2026." Since September 2, 2025, Meta flags custom and lookalike audiences that suggest financial status (its examples include "high income") or health conditions, and a flagged audience can't be used as a lookalike seed.

How many closed-won customers do I need?

At least 100 people in the source, and Meta generally recommends 1,000 to 5,000. Those are people Meta matched, not rows you uploaded, and B2B lists often match poorly: at a 20% match rate, you need about 500 contacts to reach 100. Check your list's Match score in Audiences, and see why Meta customer list match rates are low with work emails to raise it.

Meta's API also wants at least 100 source people in one country, unless you allow international seeds. If you still fall short:

  • Add every known contact at your customer accounts, not just the deal contacts.
  • Seed from conversions instead. Meta's API offers campaign conversion lookalikes, which need at least 100 conversions (200 or more recommended).
  • Send CRM lead stages back to Meta so delivery learns from qualified leads; see how to send HubSpot or Salesforce lead stages to Meta.

How do I build it in Ads Manager?

You need admin or advertiser permissions on the ad account. Then:

  1. Export the seed from HubSpot or Salesforce with every identifier you have: email (up to 3 columns), phone with country code, first name, last name, city, state, ZIP and country. Add a numeric value column if you want a value-based lookalike.
  2. Create the customer list. In Ads Manager, open Audiences, select Create audience, then Custom audience, Customer list and Next. Choose Inclusions or exclusions, since an Only exclusions list can't be used to make a lookalike. Upload the file, answer the customer value prompt, accept the custom audience terms, map identifiers, and select Import and create.
  3. Create the lookalike. Select Create audience, then Lookalike audience, and choose your customer list as the source. Saved audiences can't be a source.
  4. Choose the size. Pick the number of lookalike audiences and a percentage with the slider. Smaller percentages match your source more closely; larger ones are bigger and broader.
  5. Select Create audience.

You no longer choose a location. Meta uses the ad set's location settings, so you'll see the estimated size only when you add the lookalike to an ad set. (The Marketing API still asks for a country or country group.) While the lookalike shows Populating, you can already run ads; Meta's help center says this can take up to 3 days, and its API docs say 1 to 6 hours. Audience not created may mean the source was too small. People in your source are left out of the lookalike.

If Meta won't let you create the customer list, see how to fix Custom Audience terms that haven't been accepted.

Should I use a value-based lookalike with deal size?

Try it if your deal sizes vary widely. A value-based lookalike finds people similar to your most valuable customers, using a customer value column in your list. Meta lets you decide what value means; its examples are order value, items ordered, membership and customer lifetime value. For B2B, use closed-won amount, annual contract value or lifetime value.

Meta's rules for the column: numbers only, with no currency symbols, as decimals or whole numbers. You choose it when you upload: select Yes, customer value is included in my customer list, then pick it from Select value column. It's also worth using one measure and one currency for every row so the values compare.

Meta doesn't say how it weighs the values, so don't assume value-based wins. Run a value-based lookalike and a standard one from the same contacts in separate ad sets, and compare the pipeline each one creates in your CRM, not just cost per lead.

Which lookalike percentage should I pick?

Start small. Meta's API defines "similarity" as the top 1% of people most like your source and "greater reach" as the top 5%, and accepts any whole percentage from 1% to 20%. You can also create several lookalikes at once and use more than one in an ad set; Meta then targets people in any of them.

Do lookalikes still work now that Advantage+ audience is the default?

They work, but mostly as a hint. Meta now starts most new campaigns in its recommended Advantage+ setup, and from Marketing API v23.0 a new ad set with default targeting gets Advantage+ audience unless you set it off. With Advantage+ audience on, any custom audience you add, including a lookalike, is a suggestion: Meta shows ads to people matching it "and other audiences when it's likely to improve performance."

To keep delivery inside the lookalike, select Further limit your audience (or Further limit the reach of your ads) and uncheck Use as a suggestion. Ads Manager then usually shows Advantage+ off for the audience. Separately, Meta turns on Advantage+ lookalike automatically for new, duplicated and draft campaigns and ad sets that use a lookalike built from a customer list, website or app audience. That also lets delivery go past the percentage you chose.

Test a lookalike against broad targeting with the same exclusions, and judge them on qualified pipeline. For when a strict audience is worth giving up Advantage+, see whether to turn off Advantage+ audience for B2B.

Should I still exclude current customers?

Yes. Meta leaves your source people out of the lookalike itself, but Advantage+ audience and Advantage+ lookalike can deliver beyond it. Add your full customer list as an excluded custom audience; Meta says that doesn't turn Advantage+ off. See how to exclude current customers and open opportunities from your ads.

Does the lookalike update as new deals close?

Only if you update the source list. In Audiences, select the list, then Edit and Add customers, or Replace customers to swap in a new file. Meta says changes to a customer list "also update any ad sets or lookalike audiences that use it," without resetting the learning phase. Its API docs say Meta refreshes a lookalike every 3 days while an ad set uses it. A customer list that hasn't been updated in over 30 days shows Outdated, which may affect delivery.

When can't I use a lookalike?

Where Tofu fits

Tofu Ads Agent connects to HubSpot or Salesforce and reads your closed-won and closed-lost deals, pipeline, sales velocity and deal size, then proposes an ICP and segments. You can use that ICP to decide which won deals belong in your seed. Tofu also plans, builds and launches Meta campaigns, staged in your own ad account switched off until a person turns them on. It doesn't create Meta customer lists or lookalike audiences, so you upload the seed and build the lookalike in Ads Manager as above. It costs a flat $2,500 a month, not a share of ad spend.

Sources

Ask Tofu next

Pick a question and Tofu Ads Agent answers it in chat.

Related answers

More on

Let an agent build your next campaign.

Tofu Ads Agent reads your CRM, plans the funnel, builds the audience and creative, and stages full campaigns across LinkedIn, Google and Meta for your approval.

Try it free Get a demo