GPT-5.6 Terra vs Claude Opus 5
OpenAI's GPT-5.6 Terra and Anthropic's Claude Opus 5 both target production language workloads, but they price and behave differently. Here is the side-by-side.
Pricing checked against provider documentation on . How we verify
The short answer
GPT-5.6 Terra is the cheaper option — roughly 2.2x less on a blended workload, and it suits balanced production workloads. Claude Opus 5 justifies its premium when you need most teams' best claude starting point.
OpenAI • GPT-5.6
$2.00 / $12.00
/ 1M tokens (input / output)
The everyday tier of the GPT-5.6 family, roughly corresponding to the old 'mini' slot but benchmarking above the previous generation's flagship. For most application backends this is the default worth trying before reaching for Sol, since it clears Claude Fable 5 on several evals at a fraction of the cost.
Anthropic • Claude 5
$5.00 / $25.00
/ 1M tokens (input / output)
A step change over Opus 4.8 on deep reasoning and long-horizon agentic work, at half Fable 5's price and with the freshest knowledge cutoff in the Claude line. Anthropic's own guidance is that most teams should benchmark Opus 5 before paying for Fable 5.
Input price
Claude Opus 5 is 2.5x the price than GPT-5.6 Terra on input tokens.
Output price
Claude Opus 5 is 2.1x the price than GPT-5.6 Terra on output tokens — usually the side that dominates the bill.
Monthly cost at three workload sizes
Standard (non-batch, non-cached) rates. Reasoning models will exceed these figures because thinking tokens bill as output.
| Workload | GPT-5.6 Terra | Claude Opus 5 | Difference |
|---|---|---|---|
| Light — 1M in / 200K out | $4 | $10 | $6 |
| Moderate — 10M in / 2M out | $44 | $100 | $56 |
| Heavy — 100M in / 20M out | $440 | $1,000 | $560 |
Specification comparison
| Attribute | GPT-5.6 Terra | Claude Opus 5 |
|---|---|---|
| Input (/ 1M tokens) | $2.00 | $5.00 |
| Output (/ 1M tokens) | $12.00 | $25.00 |
| Cached input | $0.20 | $0.50 |
| Context window | 1,048,576 tokens | 1,000,000 tokens |
| Max output | 128,000 tokens | 128,000 tokens |
| Native reasoning | Yes | Yes |
| Knowledge cutoff | 2026-02 | 2026-05 |
| Relative latency | medium | medium |
| Open weights | No | No |
| API model ID | gpt-5.6-terra | claude-opus-5 |
| Status | stable | stable |
GPT-5.6 Terra: Cut 20% from the $2.50/$15 launch price on 2026-07-30.
Choose GPT-5.6 Terra if…
- Customer support and chat backends
- RAG and document processing pipelines
- Mid-complexity coding tasks
- Tool-calling agents at scale
Choose Claude Opus 5 if…
- Agentic engineering with a cost ceiling
- Deep research and analysis
- Test-time compute scaling
- Production assistants needing recent knowledge
Frequently asked
Is GPT-5.6 Terra or Claude Opus 5 cheaper?
GPT-5.6 Terra is cheaper. On a blended 3:1 input-to-output workload it costs about 2.2x less than Claude Opus 5.
Which has the larger context window, GPT-5.6 Terra or Claude Opus 5?
GPT-5.6 Terra has the larger window at 1.05M tokens versus 1M.
Should I use GPT-5.6 Terra or Claude Opus 5?
Pick GPT-5.6 Terra for balanced production workloads. Pick Claude Opus 5 for most teams' best claude starting point. If cost dominates the decision, GPT-5.6 Terra wins; if you need the capability ceiling, benchmark both on your own evals before committing.