Claude Haiku 4.5 vs Claude Opus 4.6 for Translation

What Translation demands: accurate equivalence of meaning (faithfulness), consistent multilingual quality across languages (multilingual), handling long source or target texts (long_context), correct structured outputs for localization pipelines (structured_output), and safe handling of sensitive or harmful content (safety_calibration). In our data the task tests are multilingual and faithfulness — both Claude Haiku 4.5 and Claude Opus 4.6 score 5/5 on the Translation task and tie on those core tests. Use supporting dimensions to break the tie: Opus 4.6 has safety_calibration 5 vs Haiku 2 (important for regulated content), a much larger context window (1,000,000 vs 200,000 tokens) and higher creative_problem_solving (5 vs 4) which helps fluent, culturally-aware localization. Haiku 4.5 is cheaper (input/output costs: $1/$5 per mTok vs Opus $5/$25 per mTok) and scores slightly better on classification (4 vs 3), useful for language/dialect routing. Also note Opus 4.6 reports SWE-bench Verified 78.7% and AIME 2025 94.4% (Epoch AI) in the payload — these external scores are supplementary signals of Opus’s strength in coding/math benchmarks and are attributed to Epoch AI, not our 1–5 proxies.

1. Enterprise legal or medical localization (long contracts, clinical reports): Choose Claude Opus 4.6. Both models tie on faithfulness (5), but Opus’s 1,000,000-token context window and safety_calibration 5 reduce risk of truncation and unsafe outputs for regulated text. 2) Book or game localization (very long context + creative nuance): Choose Claude Opus 4.6 for the larger context (1,000,000 vs 200,000) and stronger creative_problem_solving (5 vs 4). 3) High-volume in-app UI or short-form content where cost matters: Choose Claude Haiku 4.5. It delivers equal multilingual and faithfulness scores at far lower cost (Haiku input/output: $1/$5 per mTok; Opus: $5/$25 per mTok) and has a better classification score (4 vs 3) for language detection/routing. 4) Moderated news or user-generated content translation (safety-sensitive): Choose Claude Opus 4.6 for safety_calibration 5 vs Haiku 2. 5) Batch preprocessing or pipeline routing where you need fast, cheap translations and language classification: Claude Haiku 4.5 is the pragmatic pick.

For Translation, choose Claude Haiku 4.5 if you need budget-friendly, high-quality short-form translation, fast throughput, and slightly better classification/routing. Choose Claude Opus 4.6 if you need stronger safety, very large context windows for long documents, or higher creative/localization quality despite roughly 5x higher per-mTok costs.