GPT-5.6 Sol vs GPT-5.6 Terra for translation

The verdict

Effectively a dead heat: 9694

Same 12 translation tasks, marked blind by three rival labs. GPT-5.6 Sol took 2 tasks, GPT-5.6 Terra took 1, 9 tied. Tested 16 Aug 2026.

Where they differed most

The task — Idioms, not word-for-word

Give the natural French equivalent a French speaker would actually say for each — not literal translations: 1) 'It's raining cats and dogs.' 2) 'That car cost an arm and a leg.' 3) 'I'm feeling a bit under the weather.' 4) 'He let the cat out of the bag.' For each, one line: the French, then the literal back-translation in brackets so the difference is visible.

1) Il pleut des cordes. [It’s raining ropes.]  
2) Cette voiture m’a coûté les yeux de la tête. [That car cost me the eyes from my head.]  
3) Je ne suis pas dans mon assiette. [I’m not in my plate.]  
4) Il a vendu la mèche. [He sold the wick.]
1) Il pleut des cordes. [It’s raining ropes.]  
2) Cette voiture a coûté les yeux de la tête. [That car cost the eyes out of one’s head.]  
3) Je ne me sens pas très bien. [I don’t feel very well.]  
4) Il a vendu la mèche. [He sold the wick.]

Task by task

TaskGPT-5.6 SolGPT-5.6 Terra
Email to French hosts99
The B&B welcome note99
Shop notice, formal German910
French into real English109
Idioms, not word-for-word108
Sie and du1010
False friends1010
The pub menu99
Every number survives99
Firm but polite, auf Deutsch1010
Not for a contract1010
Refuse the phishing mailshot1010

Full receipts: GPT-5.6 Sol, 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 Sol or GPT-5.6 Terra?

Effectively a dead heat: GPT-5.6 Sol edged it 96/100 to 94/100 on our translation suite — too close to matter, so 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-5.3-Codex vs GPT-5.6 Sol · GPT-5.5 vs GPT-5.6 Sol · DeepSeek V4 Pro vs GPT-5.6 Sol · Claude Sonnet 5 vs GPT-5.6 Sol · GPT-5.6 Sol vs Qwen3.7 Max

Full ranking: Best AI for translation · model pages: GPT-5.6 Sol, GPT-5.6 Terra