Why are my mobile text message (SMS) charges higher than expected from Amazon SNS and Amazon Pinpoint?

Resolution

If your messages have more than a single message part, then you might incur unexpectedly high charges from Amazon SNS and Amazon Pinpoint SMS. A single SMS message can contain up to 140 bytes of information. This means that messages that exceed this limit or contain many multi-byte characters are divided into several parts. These parts send as separate messages, which means that there are extra charges for each message. Depending on the carrier, these messages typically reassemble on the recipient's device and appear as a single long message instead of several small messages. The number of characters that you can include in a single SMS message depends on the type of characters that the message contains. If your message only uses the GSM 7-bit alphabet, then the message can contain up to 160 characters. If the message contains any characters that are outside the GSM 03.38 character set, then message can have up to 70 characters. For more information about SMS character limits, see SMS character limits in Amazon Pinpoint.

Calculate your costs for Amazon SNS and Amazon Pinpoint

To estimate your charges in Amazon SNS and Amazon Pinpoint, use the following calculation for a message's cost:

messagePriceInDollars = (carrierFeePerMessagePartsInDollars (if there) * totalMessageParts) + (messagepricePerMessagePartsInDollars * totalMessageParts)

To verify the cost of a message, check your delivery logs in Amazon CloudWatch for the numberOfMessageParts metric.

Change your quota settings

For Amazon SNS, you can set the maximum price in USD that you want to spent on SMS messages. To do this, set the attribute AWS.SNS.SMS.MaxPrice in your publish request. If the corresponding message incurs a cost that exceeds your maximum price, then the delivery fails with the message "This delivery would exceed max price".

You can also request an increase to your monthly SMS cost limits through AWS Support. For more information, see Requesting increases to your monthly SMS spending quota for Amazon SNS.

Related information

Amazon Pinpoint pricing

Worldwide SMS pricing

Publishing to a mobile phone