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SMS Billing

Per-Segment Billing

Per-segment SMS billing currently applies to FlyNumbers in the United States, Mexico, and Lithuania.

Other SMS-enabled countries—such as Israel Mobile and Netherlands Mobile—receive incoming SMS at no charge. Check our coverage page for the full list of SMS-enabled numbers.

Incoming SMS messages to your FlyNumber are billed per segment based on the country where your number is located and the type of sender. This guide explains how SMS charges work and what factors affect pricing.

How SMS Billing Works​

When someone sends a text message to your FlyNumber:

  1. The message is received and forwarded to your configured email
  2. A small charge is deducted from your prepaid balance
  3. The charge is based on the number of segments in the message
note

SMS charges are deducted automatically from your prepaid balance. If your balance is too low, the message will be blocked until you add funds.

Understanding SMS Segments​

A single text message isn't always billed as one unit. Longer messages get split into multiple segments, and each segment is charged separately.

What is a Segment?​

Think of a segment as a "packet" that carries your text. Standard SMS technology has limits on how much text fits in one packet:

Message TypeSingle Segment LimitMulti-Segment Limit
Standard text (GSM-7)160 characters153 characters per segment
Unicode text (UCS-2)70 characters67 characters per segment

Why the difference for multi-segment messages?

When a message is too long for one segment, extra header data is added to help your phone reassemble the pieces in the correct order. This header takes up 7 characters (GSM-7) or 3 characters (Unicode), reducing the available space per segment.

Standard Text vs. Unicode​

Standard text (GSM-7) includes:

  • Letters A-Z (upper and lowercase)
  • Numbers 0-9
  • Common punctuation: . , ! ? - ( ) / :
  • Space and line breaks

Unicode (UCS-2) is required when a message contains:

  • Emojis
  • Characters from non-Latin scripts (Chinese, Arabic, Cyrillic, Hebrew, etc.)
  • Special symbols not in the GSM-7 set
Extended Characters Count Double

Some characters are technically GSM-7 but use an escape sequence, counting as 2 characters:

[ ] { } \ ^ ~ | and the Euro sign

A message with several brackets or currency symbols will reach the segment limit faster than expected.

Segment Calculation Examples​

Example 1: Short standard message

Message: "Your verification code is 847291"

  • Character count: 35
  • Encoding: GSM-7 (all standard characters)
  • Segments: 1
Example 2: Longer standard message

Message: A 200-character business notification

  • Character count: 200
  • Encoding: GSM-7
  • Calculation: 200 ÷ 153 = 1.31 → rounds up to 2
  • Segments: 2
Example 3: Message with emoji

Message: "Thanks for your order! 🎉"

  • Character count: 24
  • Encoding: UCS-2 (emoji requires Unicode)
  • Single segment limit: 70 characters
  • Segments: 1
Example 4: Longer Unicode message

Message: An 80-character message in Chinese

  • Character count: 80
  • Encoding: UCS-2 (non-Latin script)
  • Calculation: 80 ÷ 67 = 1.19 → rounds up to 2
  • Segments: 2

SMS Rates by Country​

Rates depend on two factors:

  1. Country where your FlyNumber is located
  2. Sender type (regular number or short code)

Regular Phone Numbers​

When the sender uses a standard phone number (7+ digits):

CountryRate per Segment
United States$0.01
Mexico$0.02
Lithuania$0.02
CanadaFree
Other countries$0.02

Short Codes​

Short codes are abbreviated numbers (typically 4-6 digits) used by businesses for marketing, two-factor authentication, and automated notifications. Examples: 87512, 72722, 55555

These carry a higher rate:

CountryRate per Segment
United States$0.02
Mexico$0.04
Lithuania$0.04
CanadaFree
Other countries$0.03
tip

Canadian FlyNumbers receive SMS at no charge regardless of sender type or message length.

Calculating Your SMS Cost​

The formula is straightforward:

Total Cost = Number of Segments × Rate per Segment

Practical Examples​

ScenarioSegmentsRateTotal Cost
US number, short text from regular number1$0.01$0.01
US number, 2-segment message from regular number2$0.01$0.02
US number, verification code from short code1$0.02$0.02
US number, long promotional SMS from short code (3 segments)3$0.02$0.06
Mexico number, standard text1$0.02$0.02
Canada number, any messageAnyFree$0.00

Insufficient Balance​

If your prepaid balance cannot cover an incoming SMS:

  1. The message is blocked - it will not be forwarded to your email
  2. You receive a notification - an email alert about the blocked message
  3. The message is logged - you can see it was attempted but not delivered
Avoid Missing Important Messages

Keep your prepaid balance topped up to ensure all incoming SMS messages are delivered. Consider setting up auto-refill to automatically add funds when your balance runs low.

Viewing SMS Charges​

SMS charges appear on your invoices alongside other account activity. Each charge includes:

  • Date and time received
  • Sender number
  • Your FlyNumber that received the message
  • Number of segments
  • Charge amount

SMS billing illustration

Best Practices​

  1. Monitor your balance

  2. Understand your usage patterns

    • If you receive many automated messages (2FA, alerts), expect higher SMS volume
    • Short code senders cost more per message
    • Long promotional messages may span multiple segments

  3. Consider message sources

    • Bank verification codes typically come from short codes
    • Marketing messages are often multi-segment
    • Personal texts from regular numbers are usually single-segment
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