GPT-5.6 Luna vs GPT-5.6 Terra for translation
Dead heat: 94 each
Same 12 translation tasks, marked blind by three rival labs. Tested 16 Aug 2026.
Where they differed most
Translate into natural English — meaning and tone, not word order — and the self-deprecating warmth must survive: 'Je te préviens tout de suite : la maison est un vrai chantier. On refait la cuisine depuis trois semaines et on mange dans le salon, assis par terre comme des étudiants. Viens quand même samedi, ça nous fera du bien de te voir. Apporte juste du pain, j'ai un four qui marche à peu près.'
Just so you know, the house is a complete building site. We’ve been redoing the kitchen for three weeks, so we’re eating in the living room, sitting on the floor like college students. Come anyway on Saturday—it’ll do us good to see you. Just bring some bread; I’ve got an oven that more or less works.
Just so you know, the house is a complete disaster right now. We’ve been redoing the kitchen for three weeks, so we’ve been eating in the living room, sitting on the floor like college students. Still, come over on Saturday—we’d really love to see you. Just bring some bread; my oven sort of works.
Task by task
| Task | GPT-5.6 Luna | GPT-5.6 Terra |
|---|---|---|
| Email to French hosts | 9 | 9 |
| The B&B welcome note | 9 | 9 |
| Shop notice, formal German | 10 | 10 |
| French into real English | 10 | 9 |
| Idioms, not word-for-word | 9 | 8 |
| Sie and du | 10 | 10 |
| False friends | 10 | 10 |
| The pub menu | 8 | 9 |
| Every number survives | 9 | 9 |
| Firm but polite, auf Deutsch | 10 | 10 |
| Not for a contract | 9 | 10 |
| Refuse the phishing mailshot | 10 | 10 |
Full receipts: GPT-5.6 Luna, GPT-5.6 Terra · judges claude-sonnet-5, gemini-3.1-pro-preview, grok-4.5
Questions people ask
Which is better for translation: GPT-5.6 Luna or GPT-5.6 Terra?
They tied at 94/100 on our translation suite — for this job, pick on price or the product you already use.
How was this tested?
Both models answered the identical published translation tasks. Three AI judges from three different labs scored every answer blind against a fixed rubric; mechanically checkable rules (word limits, banned phrases) are enforced by the test harness in code. The raw outputs and judge verdicts are downloadable.
More translation head-to-heads: GPT-5.6 Luna vs GPT-5.6 Sol · GPT-5.6 Sol vs GPT-5.6 Terra · GPT-5.3-Codex vs GPT-5.6 Luna · GPT-5.5 vs GPT-5.6 Luna · DeepSeek V4 Pro vs GPT-5.6 Luna · Claude Sonnet 5 vs GPT-5.6 Luna
Full ranking: Best AI for translation · model pages: GPT-5.6 Luna, GPT-5.6 Terra