What is a dirty email list costing you?

Invalid addresses don't just bounce. You pay your email platform to store them, you burn send volume on them, and the bounces they cause push your good mail into spam. Put in your numbers and see the yearly total.

No account required
Public benchmarks — sources listed
1M+ addresses verified monthly

Contacts

on your list

−

25,000

+

1K — 250K

Emails sent

every month

−

50,000

+

0 — 600K

=

You're losing

to addresses that can't receive

$21,150

PER YEAR

Monthly
Yearly

Assumes 22% of an uncleaned list is undeliverable, $0.015 per contact in platform fees, and $0.10 of revenue per delivered email — the public benchmarks for B2B list decay.

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Three costs, only one of which shows up on an invoice

Most teams notice the platform bill. The other two are larger and quieter.

Visible

Platform spend

Email platforms price by contact count, not by contacts that work. Every dead address sits in your tier and rounds your bill upward every month.

Hidden

Wasted send volume

Sending to an address that no longer exists consumes the same quota as a real one, and returns nothing — no open, no click, no reply.

Compounding

Deliverability damage

This is the expensive one. Bounces tell mailbox providers you don't know your audience, so the mail that would have converted starts landing in spam.

The threshold that changed everything

Above 2% bounces, Gmail stops asking politely

Bounce rate used to be a soft metric. It isn't any more. Gmail permanently rejects senders that cross a 2% hard-bounce rate, and Microsoft enforces the same limit. That turns list hygiene from a nice-to-have into a condition for reaching the inbox at all.

2

%

Hard-bounce ceiling at Gmail and Microsoft

0.1

%

Spam complaint rate expected of all senders

20–30

%

Annual decay of an untouched B2B list

How to bring the
‍number down

Cleaning is one step. Keeping it clean is what stops the cost from returning next quarter.

01

Clean what you already have

Upload the list and get a status per address — valid, invalid, catch-all or unknown. Remove the invalid ones before the next campaign, not after it bounces.

02

Stop bad addresses at the source

Validate at the point of entry with the API, so a typo in a signup form never becomes a record in your CRM. This is what keeps the list from decaying back.

03

Prepare the inbox before the important send

A clean list still needs a sender with history. The Warm-up Tool ramps your volume gradually so a new domain or inbox isn't judged on a sudden spike.

Methodology

MethodologyWasted platform spend multiplies your invalid contacts by a blended per-contact price drawn from published list tiers, over twelve months. Wasted sends multiplies monthly volume by the invalid rate. Revenue at risk combines bounced sends with a deliverability penalty applied once the bounce rate passes 2%, priced at your revenue-per-delivered-email figure.
Every result is shown as a range, from a ±25% band on the invalid rate, because list decay is an estimate and a single number would imply a precision this doesn't have.Sources: published ESP pricing tiers · Gmail sender requirements · Microsoft sender requirements · industry list-decay benchmarks.

FAQs

Questions about list cost

How accurate is an email list cost estimate?

Why can't I just remove bounces after the campaign?

What counts as a “dirty” email list?

What is an acceptable email bounce rate?

How often should I verify my email list?

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