GPT-5.6 Terra vs Claude Sonnet 5
OpenAI's GPT-5.6 Terra and Anthropic's Claude Sonnet 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
Claude Sonnet 5 is the cheaper option — roughly 1.1x less on a blended workload, and it suits fast claude-quality reasoning at scale. GPT-5.6 Terra justifies its premium when you need balanced production workloads.
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
$2.00 / $10.00
/ 1M tokens (input / output)
The workhorse Claude tier: a full million tokens of context and adaptive thinking at $2/$10, which undercuts the previous Sonnet 4.6 generation by a third on input while raising the context ceiling fivefold. The default pick for latency-sensitive products that still want Claude's writing and tool-use behaviour.
Input price
Claude Sonnet 5 is effectively identical than GPT-5.6 Terra on input tokens.
Output price
Claude Sonnet 5 is 17% cheaper 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 Sonnet 5 | Difference |
|---|---|---|---|
| Light — 1M in / 200K out | $4 | $4 | $0 |
| Moderate — 10M in / 2M out | $44 | $40 | $4 |
| Heavy — 100M in / 20M out | $440 | $400 | $40 |
Specification comparison
| Attribute | GPT-5.6 Terra | Claude Sonnet 5 |
|---|---|---|
| Input (/ 1M tokens) | $2.00 | $2.00 |
| Output (/ 1M tokens) | $12.00 | $10.00 |
| Cached input | $0.20 | $0.20 |
| 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 | 2026-01 |
| Relative latency | medium | low |
| Open weights | No | No |
| API model ID | gpt-5.6-terra | claude-sonnet-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 Sonnet 5 if…
- Production chat and copilots
- Long-document analysis
- Tool-heavy agents needing fast turns
- Code review and PR automation
Frequently asked
Is GPT-5.6 Terra or Claude Sonnet 5 cheaper?
Claude Sonnet 5 is cheaper. On a blended 3:1 input-to-output workload it costs about 1.1x less than GPT-5.6 Terra.
Which has the larger context window, GPT-5.6 Terra or Claude Sonnet 5?
GPT-5.6 Terra has the larger window at 1.05M tokens versus 1M.
Should I use GPT-5.6 Terra or Claude Sonnet 5?
Pick GPT-5.6 Terra for balanced production workloads. Pick Claude Sonnet 5 for fast claude-quality reasoning at scale. If cost dominates the decision, Claude Sonnet 5 wins; if you need the capability ceiling, benchmark both on your own evals before committing.