--- title: "How SMS segments work for SMS alerts" description: "Why SMS is billed per segment, how character limits and emojis change the segment count, and how to keep costs down." url: https://help.stoqapp.com/account/how-sms-segments-work/ product: "Account & billing" section: "SMS charges" last_updated: 2026-10-14 --- # How SMS segments work for SMS alerts > Why SMS is billed per segment, how character limits and emojis change the segment count, and how to keep costs down. STOQ's SMS charges are based on **segments**, the individual text units carriers transmit and bill separately. You're charged per segment, not per message, so a message that splits into two segments costs twice as much as a one-segment message. Understanding segments helps you write concise templates and keep your SMS costs predictable. ## Why segments matter - **Control costs.** You're charged per segment. A 2-segment SMS costs twice a 1-segment one. - **Write effective templates.** Character limits push you to keep the key information tight. - **Predict spending.** Knowing your average segments per message lets you estimate the monthly cost. - **Improve reliability.** Very long, multi-segment messages can occasionally arrive out of order. ## What is a segment A segment is a billable unit of text. How many characters fit in a segment depends on the encoding, and the encoding depends on which characters you use. ### GSM-7 (standard characters) Used for letters, numbers, spaces, and common punctuation: | Segments | Capacity | |---|---| | 1 segment | up to 160 characters | | 2 segments | up to 306 characters (153 per segment) | | 3 segments | up to 459 characters | Multi-segment messages reserve about 7 characters per segment to stitch the parts together. ### UCS-2 (special characters) Triggered by emojis, accented letters, non-Latin scripts, or special symbols: | Segments | Capacity | |---|---| | 1 segment | up to 70 characters | | 2 segments | up to 134 characters (67 per segment) | | 3 segments | up to 201 characters | Even a single special character switches the whole message to UCS-2, which sharply cuts the capacity. ### Quick reference | Encoding | 1 segment | Each extra segment | |---|---|---| | GSM-7 | 160 chars | 153 chars | | UCS-2 | 70 chars | 67 chars | ## How STOQ counts characters While you edit an SMS, the content editor shows a **Total characters** counter and the resulting **segment** count. It recommends keeping messages short because two things add length beyond what you type: - **Unsubscribe text** is appended to every SMS automatically (required for compliance) and counts toward the total. - **Variables expand.** A placeholder like `{{product.title_incl_variant}}` becomes the actual product name when sent, which is usually longer than the variable itself. So a template that looks like 120 characters in the editor can send as 170+ characters and split into two segments. ## Examples - **Short (1 segment):** "Hi! {{product.title}} is back in stock. Grab yours: {{product.purchase_link}}" renders to roughly 135 characters and stays 1 GSM-7 segment. - **Longer (2 segments):** "Great news! {{product.title_incl_variant}} is back at {{shop.name}}. Limited stock, order now: {{product.purchase_link}}" renders to about 210 characters and becomes 2 segments. - **Emoji (2 segments):** "🎉 {{product.title}} is back! Shop now: {{product.purchase_link}}" is short, but the emoji forces UCS-2, so the 70-character single-segment limit is exceeded and it becomes 2 segments. At $0.025 per segment (US and Canada), 500 alerts a month costs $12.50 as 1-segment messages, but $25.00 if each splits into 2 segments. ## Tips to keep the segment count low - Keep the editor's **Total characters** under about 140. - Avoid emojis and special symbols (they switch you to UCS-2). - Use `{{product.title}}` instead of `{{product.title_incl_variant}}` where you can. - Preview with a sample product name to see the rendered length before you rely on it. - Cut unnecessary words, and use a short or branded purchase link. ## Where to view segment usage 1. **Open your usage** 1. In the left menu of the STOQ app, click **Plans**. 2. On the **Usage** card, click the **Back in stock alerts** count. 3. In the breakdown, review the SMS totals and segments sent this month. ## Troubleshooting ### Charges are higher than expected Your messages are probably splitting into multiple segments. Check the **Total characters** count in the editor and shorten the message. ### It says 2 segments even though I'm under 160 characters Variables expand when sent, so the rendered message is longer than the template. Use the editor's preview with a sample product name to see the real length. ### 2 segments with no emoji A hidden special character (a curly quote, a long dash, or an accented letter) forces UCS-2, which drops the limit to 70 characters. Replace it with a standard character. ## FAQ ### How are segments charged? Each segment is charged at the per-segment rate for the destination country, so a 2-segment message costs twice a 1-segment one. See [SMS alert pricing and charges](https://help.stoqapp.com/account/sms-alert-pricing-and-charges/). ### Do emojis really change the cost? Yes. A single emoji switches the message to UCS-2, cutting the single-segment limit from 160 characters to 70, which usually adds a segment. ### Does the unsubscribe text count? Yes. The mandatory unsubscribe text is appended to every SMS and counts toward the total characters. ### Can I see the exact segment count before sending? The editor's character counter and preview are your best guide. The carrier sets the final segment count at delivery, and per-message breakdowns aren't shown in the app. ## Related guides - [SMS alert pricing and charges](https://help.stoqapp.com/account/sms-alert-pricing-and-charges/): Per-segment prices by country and how billing works. - [Set up SMS alerts](https://help.stoqapp.com/back-in-stock/back-in-stock-sms-alerts/): Turn on SMS, verification, and cost. - [Check your plan usage and remaining alerts](https://help.stoqapp.com/account/back-in-stock-plan-usage/): See alerts and segments sent this month.