Claude Sonnet 5 vs GPT-5.6 Terra
GPT-5.6 Terra comes out ahead on 11 of 14 shared measures, and the two rank 28 and 37 of 51 overall. Claude Sonnet 5 is 1.1× cheaper per million tokens (blended) — A$9.83 vs A$10.67 per 1,000 replies of customer support replys.
Where each one wins.
GPT-5.6 Terra ranks 28th of 51; Claude Sonnet 5 ranks 37th.
GPT-5.6 Terra ranks 14th of 42; Claude Sonnet 5 ranks 22nd.
GPT-5.6 Terra ranks 16th of 41; Claude Sonnet 5 ranks 19th.
GPT-5.6 Terra ranks 18th of 51; Claude Sonnet 5 ranks 27th.
GPT-5.6 Terra ranks 12th of 51; Claude Sonnet 5 ranks 14th.
GPT-5.6 Terra ranks 26th of 50; Claude Sonnet 5 ranks 33rd.
Claude Sonnet 5 is 1.1× cheaper per million tokens (blended) — A$9.83 vs A$10.67 per 1,000 replies of customer support replys.
GPT-5.6 Terra writes 1.3× faster (92 tok/s vs 73 tok/s).
Both can be used from Australia through their makers’ own APIs (Anthropic and OpenAI), which may process requests outside Australia. Claude Sonnet 5 can run with requests kept in Australia on AWS Bedrock in Melbourne. GPT-5.6 Terra can be called from AWS Bedrock in Sydney and Melbourne and Microsoft Azure in Australia East, but only through global routing, so requests may be processed outside Australia.
Side by side.
“Level” means the gap is inside LMArena’s confidence interval, or the scores are identical. Independent test scores are for each model’s headline setting. Both models can be used from Australia through their makers’ APIs; the Australian rows show whether requests can also be processed in Australia.
| BENCHMARK | CLAUDE SONNET 5 | GPT-5.6 TERRA | LEADS |
|---|---|---|---|
| AA Intelligence Index | 38.2 | 42.1 | GPT-5.6 Terra |
| AA Coding Index | 71.5 | 76.7 | GPT-5.6 Terra |
| GPQA Diamond | 91.1% | 92.5% | GPT-5.6 Terra |
| Humanity’s Last Exam | 41.3% | 42.9% | GPT-5.6 Terra |
| AA-LCR | 82.0% | 83.0% | GPT-5.6 Terra |
| Terminal-Bench 2.1 | 80.5% | 88.0% | GPT-5.6 Terra |
| τ²-Bench (banking) | 37.3% | 40.2% | GPT-5.6 Terra |
| SciCode | 54.3% | 55.0% | GPT-5.6 Terra |
| LMArena Text | 1461 | 1466 | Level |
| LMArena WebDev | 1538 | 1518 | Claude Sonnet 5 |
| LMArena Vision | 1266 | 1267 | Level |
| LMArena Document | 1476 | 1477 | Level |
| LMArena Search | 1196 | ||
| LMArena Agent | #9 | #23 | Claude Sonnet 5 |
| Blended price (AUD) | A$5.62 | A$6.32 | Claude Sonnet 5 |
| Output speed | 73 tok/s | 92 tok/s | GPT-5.6 Terra |
| Answer starts after | 1.4 min | 2.9 min | Claude Sonnet 5 |
| Context window | 1,000,000 tokens | 1,050,000 tokens | GPT-5.6 Terra |
| USE FROM AUSTRALIA | |||
| Maker’s API | YES | YES | |
| Processed in Australia | YES · CLOUD | NO | |
| AUSTRALIAN CLOUD REGIONS | |||
| AWS Bedrock · Sydney | GLOBAL | GLOBAL | |
| AWS Bedrock · Melbourne | IN REGION | GLOBAL | |
| Azure · Australia East | NOT IN AU | GLOBAL | |
| Google Vertex AI · Sydney | GLOBAL | NOT OFFERED | |
The same jobs, in Australian dollars.
List prices at the snapshot’s RBA rate, excluding GST and reasoning tokens.
| JOB | CLAUDE SONNET 5 | GPT-5.6 TERRA | MEDIAN MODEL |
|---|---|---|---|
| Customer support replyPER 1,000 REPLIES | A$9.83 | A$10.67 | ≈ A$6.58 |
| Summarise a 30-page documentPER 100 DOCUMENTS | A$6.74 | A$6.96 | ≈ A$4.74 |
| Agentic coding taskPER 10 TASKS | A$5.33 | A$5.56 | ≈ A$3.72 |
Each model in full.
Claude Sonnet 5 or GPT-5.6 Terra?
Is Claude Sonnet 5 better than GPT-5.6 Terra?
On our overall leaderboard GPT-5.6 Terra ranks 28th and Claude Sonnet 5 37th of 51. Which is better depends on the job: the table above compares each benchmark, price and Australian availability.
Which is cheaper, Claude Sonnet 5 or GPT-5.6 Terra?
Claude Sonnet 5, at A$5.62 per million tokens (blended) against A$6.32 for GPT-5.6 Terra. Reasoning-heavy settings add output tokens, so real bills depend on the effort level you run.
Can I use Claude Sonnet 5 and GPT-5.6 Terra in Australia?
Both can be used from Australia through their makers’ own APIs (Anthropic and OpenAI), which may process requests outside Australia. Claude Sonnet 5 can run with requests kept in Australia on AWS Bedrock in Melbourne. GPT-5.6 Terra can be called from AWS Bedrock in Sydney and Melbourne and Microsoft Azure in Australia East, but only through global routing, so requests may be processed outside Australia.
Ratings: LMArena leaderboard dataset (CC BY 4.0), rescaled for the lens scores · leaderboards to 22 Sep 2026
Evaluations, prices and speed: Artificial Analysis (artificialanalysis.ai) · fetched 23 Sep 2026
Exchange rate: Reserve Bank of Australia, table F11.1 · A$1 = US$0.7123 on 22 Sep 2026 · prices exclude GST
Snapshot 23 Sep 2026 · updated weekly · How the rankings work →