This article explains how email usage, contact storage, and overages are billed.

Monthly Billing Overview

Critical Impact bills:

• At the beginning of the month for your contracted usage

• In arrears for any overages incurred in the previous month

Your invoice will include:

• Your monthly usage allocation

• Any additional email or storage overages from the prior month

• Any add-ons associated with your account

All invoices are due upon receipt.

Email Sending Limits

Your account includes a defined number of emails you may send each month.

If you exceed your monthly sending limit:

• Additional emails are billed at your contracted overage rate

• Overage charges appear on the following month’s invoice

• Unused email volume does not roll over

Contact Storage Limits

Your plan includes storage for a set number of unique email contacts.

If you exceed that limit, additional storage blocks are billed.

Watermark Billing

Subscriber billing is based on a watermark method.

You are billed based on:

The highest number of subscribers in your account on any single day during the billing period.

If your list increases temporarily — even for one day — that peak number becomes your billable storage count for that month.

An Example: Email & Subscriber Overages

Below is a simplified example showing how overages are calculated.

Email Overage Example

Monthly Email Limit: 500,000
Emails Sent: 550,000
Overage Rate: $0.005 per email

Overage Calculation:

550,000 – 500,000 = 50,000 excess emails

50,000 × $0.005 = $250 in email overage charges

That $250 would appear on the following month’s invoice.

Subscriber Storage Example - Watermark Billing

Subscriber Limit: 200,000
Highest Subscriber Count During Month: 221,000
Overage Rate: $100 per block of 10,000 subscribers

Step 1: Determine Overage Amount

221,000 – 200,000 = 21,000 subscribers over the limit

Step 2: Apply Block Billing

Storage overages are billed in blocks of 10,000.

21,000 exceeds two full 10,000 blocks, so billing rounds up to the next full block.

That equals 3 blocks of 10,000.

3 × $100 = $300 in storage overage charges

Why This Matters

If your account:

• Started the month at 198,000 subscribers

• Increased to 221,000 after a list upload

• Then dropped to 199,500 later in the month

Your billable count would still be 221,000.

Because billing is based on the highest subscriber count reached during the month, the temporary peak becomes the watermark.

How Subscriber Status Affects Billing

Not all subscriber statuses are treated the same for billing purposes.

Subscribers That Count Toward Billing

Subscribers are considered active (and billable) if they are not marked as:

“Unsubscribed from all”

Subscribers who:

• Are removed from individual lists

• Are not currently receiving campaigns

• Exist in your database but are inactive operationally

Still count toward your billed subscriber total if they are not marked “Unsubscribed from all.”

These subscribers retain the ability to receive emails from your account and are therefore included in your storage count.

“Unsubscribed from All” Status

When a subscriber is marked Unsubscribed from all:

• They can no longer receive any email from your Critical Impact account.

• Their record remains stored to ensure compliance with unsubscribe requirements.

• They do not have the ability to receive future messaging.

It is important to honor unsubscribe requests. Critical Impact retains these records to protect compliance and prevent accidental re-mailing.

Sub Account Billing

Sub accounts can have one of three statuses:

• Active

• Suspended

• Deleted

Active and Suspended Sub Accounts

Both active and suspended sub accounts:

• Count toward your total number of sub accounts

• Are included in billing

Suspended accounts remain part of your environment and are still billable.

Sub Account Watermarks

In environments that use sub accounts, subscriber peaks are recorded at the sub account level as well as the overall parent account level. Each sub account’s highest subscriber count during the billing period contributes to the parent account’s overall watermark.

Because of this, removing subscribers from one sub account and then adding subscribers to another during the same billing cycle does not offset the earlier peak. If a sub account reaches a higher subscriber count at any point in the month, that peak remains part of the account’s watermark for that billing period even if subscribers are later removed.

Suspended Sub Accounts Only

Suspended sub accounts are unique in that they do not count your active subscribers toward your total number of active subscribers. This is a feature exclusive to suspended accounts that allows an account holder the ability to put an account in a suspended status while being charged for the account in order to keep the subscriber data suspended temporarily. 

Deleted Sub Accounts

Deleted sub accounts:

• Do not count toward your total

• Are not billed

If a sub account is no longer needed, it must be deleted — not suspended — to stop billing.

How to Avoid Unnecessary Storage Charges

Before uploading new contacts:

• Remove inactive or outdated subscribers first

• Suppress records you no longer need

• Review your current subscriber count

Adding contacts before cleaning your list may temporarily increase your watermark and result in additional billing.

When managing sub accounts, removing subscribers from one sub account does not create capacity to add subscribers to another during the same billing cycle. Each sub account’s highest subscriber count reached at any point during the month contributes to the overall account watermark, even if subscribers are later removed.

Final Invoice After Service Ends

Because overages are billed in arrears, you may receive a final invoice after your agreement ends.

If email or storage overages occurred during your last month of service, those charges will appear in a final (13th month) invoice.

Billing Questions

If you believe an invoice is incorrect, contact us within 30 days of the billing date for review.

billing@criticalimpact.com
(888) 681-0966