SMS Length & Cost Calculator (Korean SMS/LMS bytes)
Before sending a bulk text message in South Korea, check whether it fits in a short SMS or becomes a long LMS, how many bytes are left, and what it will cost for your recipient list. Bytes are counted the EUC-KR way (Korean characters 2 bytes, Latin letters, digits and spaces 1 byte), and you enter your own provider's prices. Nothing you type leaves this browser.
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When to use it
Check an appointment reminder fits in one SMS
Paste the reminder and the byte count and SMS/LMS type appear at once, along with how many bytes to cut if it spills into LMS.
Compare one LMS with several SMS
Enter both SMS and LMS prices to see the cost of one long message next to the cost of splitting it into several short ones.
Spot characters that may break
Characters that do not exist in EUC-KR, such as emoji, are listed separately because some providers break or reject them.
How to use
- Paste or type the message. The byte count and SMS/LMS type update as you type.
- Choose the SMS limit (90 or 80 bytes) and how line breaks are counted to match your provider. Tick "Photo attached" for MMS.
- Enter your per-message prices and the number of recipients to see the total.
How it counts
- Bytes: EUC-KR (CP949): Latin letters, digits, spaces and basic symbols are 1 byte; Korean, Hanja and full-width symbols are 2 bytes. The table is built from the browser's own EUC-KR decoder.
- SMS or LMS: Up to the SMS limit (90 bytes by default) is SMS, longer up to 2,000 bytes is LMS, and a message with a photo is MMS. Providers may use 80 bytes for SMS or other LMS limits.
- Line breaks: Some providers count a line break as 1 byte and some as 2 (CR+LF), so you can choose.
- Cost: Per-message price × recipients. Prices can have two decimal places and are calculated as whole hundredths of a won, so there are no rounding errors.
Frequently asked questions
How many bytes is one SMS in Korea?
Bulk messaging providers commonly use 90 bytes and phones often use 80 bytes. It depends on the provider, so pick the matching SMS limit.
How many bytes is a Korean character?
In EUC-KR, which text messaging commonly uses, each Korean character is 2 bytes and Latin letters, digits and spaces are 1 byte. So 90 bytes is 45 Korean characters.
Why are there no default prices?
Per-message prices vary by provider, plan, top-up amount and whether VAT is included, so you enter your own.
What happens with emoji?
Emoji are not in EUC-KR, so some providers break or reject them. The tool lists them and counts each as 2 bytes.
Is my text sent to a server?
No. Everything is calculated on this page, and your text and prices are saved only in this browser so you can continue later.
Last checked: October 24, 2026 · Dagochim team