Guide

How email platforms bill for contacts, and what duplicates add

Email platforms bill by the contacts you store, the profiles that can be emailed, or the emails you send, and they differ on whether opted-out contacts count. One person held as two subscribed contacts is counted twice. Find which count your plan uses, then compare contacts with the people behind them.

By MergeGuard team

Last updated October 25, 2026

6 min read

On this page

What each platform counts
Who pays for opted-out contacts
Where duplicates enter the count
Estimate what duplicates add
Overages and timing
Before you remove anyone
Self-assessment
Sources

Your email bill is built on a count. If that count includes the same person twice, you pay for the second copy. This guide explains the usual ways platforms count, where duplicate Shopify customers enter that count, and how to put a number on it for your own plan. Prices and limits here were checked on October 24, 2026. Platforms change them, so check your own billing page.

Key insight

Platforms differ on whether opted-out contacts are billed, so a cleanup saves money on some and not on others.

What each platform counts

Email platforms tend to price plans in one of three ways: by contacts or profiles stored, by emails sent, or by both. The table sets out four platforms. Check your own plan’s pricing page and billing settings to see which applies to you.

Platform	What is billed	What drops out	What duplicates add
Klaviyo	Active profiles, plus emails sent in the billing cycle. An active profile is “Any profile, regardless of consent status, that can be emailed through Klaviyo”.	Suppressed profiles, once suppression is processed. A phone number alone doesn’t count toward the plan.	Two emailable profiles for one person count as two. A profile with several addresses counts once (Multi Email Profiles).
Shopify Email	Emails sent, counted “based on each individual email address that an email activity is sent to”. 10,000 free a month on Basic, Grow, Advanced and Plus, then $1 per 1,000 up to 300,000.	Abandoned checkout automations, which are free and don’t count toward the limit.	A person on two subscribed addresses uses two of the free emails on every campaign.
Mailchimp	Contacts. Subscribed, unsubscribed and non-subscribed contacts are all included. The limit is the most you store at any point during your billing cycle.	Archived, cleaned and deleted contacts.	Both addresses count, and an opted-out address still counts until you archive it.
Omnisend	Billable contacts, which are subscribers plus non-subscribers, billed upfront each 30-day cycle.	Only unsubscribed contacts, the ones who opted out.	Two subscribed contacts count twice, and non-subscribed contacts are billable too.

Klaviyo’s pricing page lists a free plan of up to 250 active profiles and 500 email sends a month. We did not use paid prices, which change often.

For Shopify Email, the “duplicates add” cell is our reasoning from how it counts, since its page doesn’t mention duplicates. For Mailchimp and Omnisend, the pages we read don’t say how a contact on several audiences or channels is counted, so this guide doesn’t either.

Who pays for opted-out contacts

This is where platforms differ most. Klaviyo leaves out suppressed profiles, and Omnisend leaves out contacts who opted out. Mailchimp counts unsubscribed contacts unless you archive them. So cleaning up opted-out contacts lowers the bill on some platforms and changes nothing on others. This comparison is our reading of the three pages, not a statement any platform makes.

Where duplicates enter the count

Your email platform builds its contact list from your store and your sign-up forms. A shopper with two Shopify profiles often has two email addresses, and two subscribed addresses usually become two contacts.

Each system decides for itself which records are the same person. Klaviyo explains its own matching rules in its guide to how it matches profiles. Its Multi Email Profiles article describes storing up to five email addresses on one profile, and says “Billing is based on profiles, not individual email addresses.” Read both to see whether either applies to your account before you assume your count is clean.

Duplicates stack up over time. One merchant saw a CSV import from Klaviyo into Shopify create new Shopify profiles instead of matching existing ones (merchant report). The new profiles then flow back as contacts.

Estimate what duplicates add

You need two numbers: subscribed contacts, and the people behind them.

Duplicate contacts = subscribed contacts − people behind those contacts
On a contact-priced plan: check whether removing the duplicate contacts would move you down a tier. If your platform charges per contact above a base, multiply duplicate contacts by that rate.
On a send-priced plan: extra sends per month = duplicate contacts × campaigns you send to that list per month

In MergeGuard’s demo store: 1,012 subscribed contacts → 926 people; 86 would get the newsletter twice Demo store (Northsail Supply). If that store sent four campaigns a month to its whole list, that would be 86 × 4 = 344 extra emails a month Demo store (Northsail Supply). The four campaigns are our assumption for the example.

Demo store (Northsail Supply)

The extra emails are the duplicate contacts times the campaigns sent.

The people count is the hard part. A spreadsheet works for a small list: group contacts that share a phone number, or emails that differ only by a typo. Leave out pairs that share only an address, because those are often two real people who live together.

Overages and timing

Going over a limit works differently on each platform. Klaviyo’s billing page says it “does not stop you from sending or adding additional profiles”, and moves you to a higher tier as of your next billing cycle. Check how your own platform handles it before a large import or a big send.

Before you remove anyone

Removing or excluding contacts happens in your email platform, and it touches consent, so go carefully.

Keep the address the person uses. Usually that is the one with recent opens or recent orders.
Leave the other out of your sends with a list or segment, which keeps their subscription as it is.
Check the count afterwards. Cleaning up customers in Shopify and cleaning up contacts in your email platform are separate jobs. Look at your platform’s contact count rather than assuming it went down.
Watch your flows. One merchant reported old abandoned-cart flows firing after merging customers in Shopify (merchant report).

If you also merge the Shopify profiles, remember Shopify’s consent rule: “If the customer is subscribed to email and SMS text marketing in one profile, but not in the other, then the merged profile is subscribed.” For the steps to stop double sends, read sending the same newsletter twice.