GPT-5.5 vs GPT-5.6 Terra for translation
Effectively a dead heat: 94–93
Same 12 translation tasks, marked blind by three rival labs. GPT-5.6 Terra took 3 tasks, GPT-5.5 took 2, 7 tied. Tested 16 Aug 2026.
Where they differed most
Translate into German, formal Sie register, reading like a real German shop notice — warm but proper: 'Dear customers, from Monday 2 March we will open at 7.30am instead of 7am. The bread delivery for pre-orders is unaffected. Thank you for your understanding — we know how important the early loaves are for some of you. The Hartley family.'
Liebe Kundinnen und Kunden, ab Montag, dem 2. März, öffnen wir um 7:30 Uhr statt wie bisher um 7:00 Uhr. Die Brotauslieferung für Vorbestellungen ist davon nicht betroffen. Vielen Dank für Ihr Verständnis — wir wissen, wie wichtig die frühen Brote für einige von Ihnen sind. Ihre Familie Hartley
Liebe Kundinnen und Kunden, ab Montag, dem 2. März, öffnen wir unsere Türen künftig um 7:30 Uhr statt um 7:00 Uhr. Die Brotlieferung für Vorbestellungen bleibt davon selbstverständlich unberührt. Vielen Dank für Ihr Verständnis – wir wissen, wie wichtig das frühe Brot für einige von Ihnen ist. Ihre Familie Hartley
Task by task
| Task | GPT-5.5 | GPT-5.6 Terra |
|---|---|---|
| Email to French hosts | 9 | 9 |
| The B&B welcome note | 9 | 9 |
| Shop notice, formal German | 9 | 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 | 9 | 9 |
| Every number survives | 8 | 9 |
| Firm but polite, auf Deutsch | 10 | 10 |
| Not for a contract | 9 | 10 |
| Refuse the phishing mailshot | 10 | 10 |
Full receipts: GPT-5.5, 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-5.5 or GPT-5.6 Terra?
Effectively a dead heat: GPT-5.6 Terra edged it 94/100 to 93/100 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 Sol vs GPT-5.6 Terra · GPT-5.5 vs GPT-5.6 Sol · GPT-5.6 Luna vs GPT-5.6 Terra · GPT-5.5 vs GPT-5.6 Luna · GPT-5.3-Codex vs GPT-5.6 Terra · DeepSeek V4 Pro vs GPT-5.6 Terra
Full ranking: Best AI for translation · model pages: GPT-5.5, GPT-5.6 Terra