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Email bounce calculator

Enter the size of your list, pick your sending platform and estimate the share of addresses that no longer exist: you see what they cost you, on the bill and at the send, and what verifying the list first costs.

Your next send

Sending platform

Your estimate, as a share of the list. Not sure? Start from a marker.

Left empty, the calculator uses a benchmark: €0.16 per email sent, Omnisend's 2025 average for online store campaigns, so €1,600 for this list. Enter your own figure to replace it.

€1,600 at risk (estimate). 300 hard bounces. At Brevo: Over the threshold.

Estimate

€1,600at risk (estimate)

What this campaign brings in: the send crosses a threshold past which Brevo can stop sending.

Estimated at €0.16 per email sent, Omnisend's 2025 average for online store campaigns. Enter what one campaign brings in to use your own figure.

300 hard bounces: 3% of 10,000 addresses, if every address that no longer exists bounces on this send.

Verify before you send

€82to verify these 10,000 addresses with PricklyMails

100,000 tokens at 10 per address: one month of the Pro plan (€32, 50,000 tokens, lists of up to 10,000 addresses) and 50,000 more tokens as a top-up (€50).

Less than the estimated revenue these dead addresses put at risk.

Verify for free

The tokens you get at signup cover about 100 addresses, no credit card needed.

At Brevo

Over the threshold

A hard bounce rate over 2%, on a campaign sent to new contacts

On 10,000 addresses: more than 200 hard bounces. This send goes 100 hard bounces past it.

Beyond it

The campaign and the account are suspended. A second suspension is not lifted, and the subscription keeps running meanwhile.

SourceBrevo

On the bill

Brevo mainly bills a monthly volume of emails: this send would spend 300 of them on addresses that no longer exist. Only once, since Brevo then blocklists an address that hard bounced.

SourceBrevo
Every published threshold

The same send, at every platform

The bar is your bounce rate, the share of your addresses that no longer exist; each pin is a threshold the platform publishes. Past a pin, the platform acts. Drag along a bar, or the slider below, to try another rate, and click a platform to pick it.

Hard bounce thresholds and your bounce rate
PlatformThresholdYour bounce rate
BrevoOver 2%, on a campaign sent to new contactsOver by 100
KlaviyoOver 2%Over by 100
HubSpot5% in a monthUnder by 200
MailjetA bounce rate over 5%Under by 200
Amazon SES5% or more for a review, 10% for a pauseUnder by 200

Mailchimp publishes no figure. Rules checked on October 21, 2026.

Your real share

The share is the one number you are guessing.

Verify about a hundred addresses picked at random from your list: you get an order of magnitude, not a precise measure, but you will know whether your next send is close to a threshold. If it is, verify the whole list before importing it, then follow each address's recommendation: send, review or remove.

The tokens you get at signup cover about 100 addresses, no credit card needed.

Verify for free Read the guide behind these figures
Method

How the estimate works

  • Every address that no longer exists counts as one hard bounce on this send. A conservative assumption: an abandoned mailbox that still accepts mail does not bounce, and stays on your list.
  • The hard bounces are your share of the list, rounded to the nearest address, and each threshold is turned into a number of addresses on your list.
  • The rules do not measure the same thing: Brevo's applies to a campaign sent to new contacts, HubSpot's to a month of sends, and Mailjet's to every bounce, soft or hard, not only hard bounces.
  • Prices are the monthly prices each platform's pricing page published on October 21, 2026, in euros: Mailchimp's Standard plan at its regular price, after the first-year discount, and MailerLite's Comfort plan, billed monthly. Brevo and Mailjet bill a volume of emails, and HubSpot and Klaviyo price their tiers in dollars only, HubSpot in its product catalog and Klaviyo on its pricing page, so the estimate quotes none for them.
  • Left empty, the campaign revenue is an estimate: $0.18 per email sent, the average revenue Omnisend measured on scheduled campaigns across 2025, from the sends of the online stores on its platform, or €0.16 at the European Central Bank's reference rate of October 21, 2026, 1.1234 dollars for one euro. It is typical of online stores, not of every list: your own figure replaces it.
  • The price of verifying is PricklyMails pricing as it stands today, for the whole list and every check the Free plan includes: the tokens you get at signup when they cover it, otherwise the cheaper of a top-up and one month of a plan.
  • Thresholds and prices checked on October 21, 2026 in each platform's own pages. A platform can change its rules and its prices: the links below lead to the current text.
SourcesBrevoKlaviyoHubSpotMailjetAmazon SESValidityMailchimpMailerLiteOmnisendEuropean Central Bank

Frequently asked questions

What counts as a hard bounce?

A permanent delivery failure: the address does not exist, or no longer does, or its domain cannot receive mail, and sending again will not change the outcome. A soft bounce is temporary, such as a full mailbox or a server that is down. The thresholds above count hard bounces, except Mailjet's, which counts every bounce, soft or hard.

Sources

What hard bounce rate is too high?

It depends on the platform: over 2% on a Brevo campaign sent to new contacts, over 2% at Klaviyo, 5% in a month at HubSpot, a bounce rate over 5% at Mailjet, and 5% at Amazon SES, which then places the account under review and may pause sending from 10%. For comparison, Validity measured an average of 1.46% across 2025.

Sources

Do sending platforms bill contacts that no longer exist?

Not for long, on most of them. Mailchimp, Klaviyo and Kit stop counting a contact once it hard bounces, and MailerLite still counts it for the current billing cycle. The cost sits elsewhere: before the first send, when the dead addresses count toward your tier, and at the send, when they push the bounce rate past a threshold.

Sources

How much can dead addresses add to the bill?

As much as the tier they push the list into. On Mailchimp's Standard plan, at the regular price, 10,000 contacts cost €121.36 a month and 10,001 contacts cost €206.76. On MailerLite's Comfort plan, billed monthly, 10,000 subscribers cost €79 and 10,001 subscribers cost €109, for the whole billing cycle. HubSpot bills the higher marketing contact tier until renewal. Prices checked on October 21, 2026.

Sources

How do I find the share of my own list?

Verify about a hundred addresses picked at random from your list. You get an order of magnitude, not a precise measure, but enough to know whether your next send is close to a threshold. The guide on the cost of dead addresses explains the method.

Source

Check your list before your next send.

1,000 tokens free when you sign up, no credit card. After that, you only pay for answers.

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