SMS length & segment calculator
Paste a message to see its encoding, how many segments carriers will bill you for, and what it costs to send. Free, no signup, runs entirely in your browser.
all-in rate; carrier fees passed through at cost — see pricing.
How SMS counting works
Carriers encode texts as either GSM-7 (the compact 7-bit alphabet covering basic Latin plus a few symbols) or UCS-2 (2-byte characters for everything else). One character outside the GSM-7 set flips the whole message to UCS-2, cutting capacity from 160 characters to 70. Long messages are split into concatenated segments of 153 (GSM-7) or 67 (UCS-2) characters — and you pay per segment. The extension characters € [ ] { } ~ ^ | \ stay GSM-7 but count double.
FAQ
How many characters fit in one SMS?
160 characters if the message only uses the GSM-7 character set. If it contains any character outside that set (emoji, smart quotes, most non-Latin scripts), the whole message is encoded as UCS-2 and the limit drops to 70 characters.
What is an SMS segment?
Messages longer than one SMS are split into segments that carriers reassemble on the phone. Each segment reserves 7 bytes for reassembly headers, so concatenated segments hold 153 GSM-7 characters (or 67 in UCS-2) instead of 160 (or 70). You pay per segment, not per message.
Why did my message switch to UCS-2?
A single character outside the GSM-7 set — an emoji, a curly apostrophe (’), an em dash, or letters from most non-Latin alphabets — switches the entire message to UCS-2. The calculator highlights exactly which characters did it.
How much does it cost to send an SMS?
Price is per segment. A 3-segment message costs three times the per-segment rate. Hail charges one flat rate per segment with carrier fees passed through at cost; the calculator lets you plug in any provider's rate.
More free tools: AI Voice Agent Cost Calculator · Email Deliverability Checker · all tools