Understanding SMS Billing & Mass Text Charges

Understanding SMS Billing & Mass Text Charges

Mass texting allows practices to instantly reach a large number of patients. However, SMS billing is not calculated only by the number of recipients.
Charges are determined by SMS segments, which depend on:
  • Number of recipients
  • Message length
  • Character encoding (GSM vs. Unicode)
  • Special characters, emojis, or formatting

How SMS Billing Works

When sending a mass text (for example, to 3,538 recipients), charges are calculated based on:

  • Number of recipients
  • Length of the message
  • Character encoding type
  • Special characters or emojis used

Each text sent may count as 1, 2, 3, or more SMS units per recipient.

Understanding SMS Character Limits

GSM Encoding (Standard Text)

  • Limit: 160 characters per SMS
  • If message exceeds 160 characters, it splits into multiple parts
  • Each part counts as 1 SMS unit

Segment Breakdown:

  • 1–160 characters = 1 unit
  • 161–306 characters = 2 units
  • 307–459 characters = 3 units

Unicode Encoding (Emojis / Special Characters)

If the message contains:

  • Emojis (🦷 😊)
  • Curly quotes (“ ”)
  • Special symbols
  • Certain punctuation

The message switches to Unicode encoding.

  • Limit: 70 characters per SMS

Segment Breakdown:

  • 1–70 characters = 1 unit
  • 71–134 characters = 2 units
  • 135–201 characters = 3 units

⚠️ Important: Even one emoji can reduce the limit from 160 to 70 characters.

Visual SMS Segment Calculation Example

Scenario:

You send a 180-character message with no emojis to 3,538 patients.

Step 1: Determine Encoding
No emojis → GSM encoding

Step 2: Determine Segments
180 characters → Falls under 161–306 range → 2 SMS units per recipient

Step 3: Calculate Total Units
3,538 recipients × 2 units = 7,076 SMS units

Step 4: Calculate Cost
7,076 × $0.01 = $70.76


Unicode Example:

Same 180-character message + 1 emoji 😊

  • Switches to Unicode
  • 180 characters → Falls under 135–201 range
  • 3 SMS units per recipient

3,538 × 3 = 10,614 units
10,614 × $0.01 = $106.14

How Charges Are Calculated

Formula:

Number of Recipients × SMS Segments = Total SMS Units

Each SMS unit = $0.01

Frequently Asked Questions

Why is my SMS usage higher than my contact list?

SMS charges are based on message length, not just the number of recipients.

If your message exceeds character limits or contains emojis/special characters, it splits into multiple segments.

Each segment counts as a separate SMS per recipient.


Why did adding one emoji increase my bill?

Adding an emoji switches the message from GSM encoding (160 characters) to Unicode encoding (70 characters).

This significantly reduces the character limit per segment, causing the message to split into more units.


How can I reduce SMS costs?

  • Keep messages under 160 characters
  • Avoid emojis
  • Avoid special symbols
  • Use simple punctuation
  • Preview character count before sending

Key Takeaway

SMS overages typically occur due to message length and Unicode characters — not system errors.

Understanding character limits helps prevent unexpected charges and allows practices to optimize messaging costs effectively.



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