API - Translator Text: Limits

The following limits apply when using the Microsoft Translator Text API:

Request size: 5000 characters.
You are charged per character, not per request, so you may as well use shorter requests and have multiple requests outstanding. Learn more about Microsoft Translator character counts.

Number of outstanding requests to the Translator service: unlimited.
You are charged per character, not per request, so you may as well use shorter requests and have multiple requests outstanding. Be sure to always pass complete sentences to the API

Number of characters per hour:
The volume of characters per hour is limited by your selected Microsoft Translator Text API subscription pricing tier in the Azure portal. This is not a guarantee that you can achieve these limits, but you are likely to receive an out of quota response if you reach these limits:

F0 tier: 2 million characters
S1 and S2 tiers: 40 million characters
S3 tier: 120 million characters
S4 tier: 200 million characters

The above applies to the Microsoft-provided generic systems. The limits apply per Microsoft Translator Text API subscription. The same limits apply per originating IP.

Custom systems using the Microsoft Translator Hub are further limited to 1800 characters per second.

Latency: 13 seconds.
Microsoft Translator has a maximum latency of 13 seconds. At that time you will have received the result or a timeout response. The typical response time for a short request is 150 to 300 milliseconds. The typical response time varies per request size and per language pair.

Sentence Length:

The maximum sentence length is 275 characters, with the following exceptions:
de: 290
pt: 290
es: 280
it: 280
ja: 150
zh: 132
th: 258

This means that the Breaksentences function will always return sentence below this number. You can still translate longer sentences.

Last update: April 10, 2018


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  2. Translator Hub replaces the Collaborative Translation Framework (CTF)
  3. Microsoft Translator Moves to the Azure portal
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  5. API and Hub: Confidentiality
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  11. API - Translator Text / Speech: Why are there two keys for my API subscription?
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  13. API - Translator Text: Using Neural MT Systems
  14. API- Translator Text: Standard category languages
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  16. API - Translator Text: Limits
  17. API - Translator Text: How Microsoft Translator counts characters
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  21. API - Translator Text: European datacenter
  22. API - Translator Text: Languages detected by the Detect() method
  23. API - Translator Text: First few Microsoft Translator API requests succeed, then the calls fail
  24. API - Translator Text: Profanity filtering in the TranslateArray() method
  25. API - Translator Speech: Signal the end of the utterance
  26. Hub: API available
  27. Hub: Translator Hub Resource Guide
  28. Hub: August 2016 Release notes
  29. Hub: Deployment of a custom system requires a Microsoft Translator Text API subscription in the Azure portal
  30. Hub: Capacity of custom Microsoft Translator Hub systems
  31. Hub: Building a custom system using a dictionary only
  32. Business Applications: Security and Privacy in Microsoft Office Products

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