AI model comparison

GPT-5.6 Terra vs Claude Sonnet 5

Pricing, context window, benchmarks, and features compared side by side. Or skip the guesswork and send one prompt to both.

GPT-5.6 Terra is a balanced model in OpenAI's GPT-5.6 series, positioned between the flagship Sol tier and the cost-efficient Luna tier.

Input / 1M
$2
Output / 1M
$12
Context
1.05M

Sonnet 5 is Anthropic's most capable Sonnet-class model, with frontier performance across coding, agents, and professional work.

Input / 1M
$2
Output / 1M
$10
Context
1M

At a glance

Quick verdict

How the two models stack up on the things people ask about most.

Lower price

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Claude Sonnet 5

1.1x cheaper for a typical chat

Higher intelligence score

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GPT-5.6 Terra

42.1 vs 38.2 on Artificial Analysis

Larger context window

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GPT-5.6 Terra

1.05M vs 1M tokens

Newer release

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GPT-5.6 Terra

Released July 9, 2026

Benchmarks

Benchmark scores

Independent scores from Artificial Analysis. Higher is better.

Intelligence index

openai logoGPT-5.6 Terra42.1
anthropic logoClaude Sonnet 538.2

Coding index

openai logoGPT-5.6 Terra76.7
anthropic logoClaude Sonnet 571.5

Agentic index

openai logoGPT-5.6 Terra43.2
anthropic logoClaude Sonnet 543.6

Pricing

GPT-5.6 Terra vs Claude Sonnet 5 API pricing

Per-token API rates. Cheaper option highlighted.

Metricopenai logoGPT-5.6 Terraanthropic logoClaude Sonnet 5
Input tokensPer 1M tokens$2$2
Output tokensPer 1M tokens$12$10
Cached input (read)Per 1M tokens$0.20$0.20
Cache writePer 1M tokens$2.50$2.50
Long-context pricingPer 1M tokens, for very long prompts$4 in / $18 out above 272KSame rate at any length
Web searchPer request$0.01$0.01

What it costs in practice

Estimated cost per 1,000 requests at standard rates. Coding and long-document figures also show the cost when the input is already cached.

Chat message

2K in, 500 out

openai logoGPT-5.6 Terra$10
anthropic logoClaude Sonnet 5$9

Coding task

30K in, 4K out

openai logoGPT-5.6 Terra$108$54 cached
anthropic logoClaude Sonnet 5$100$46 cached

Long document summary

150K in, 2K out

openai logoGPT-5.6 Terra$324$54 cached
anthropic logoClaude Sonnet 5$320$50 cached

Specs

Context window and capabilities

How much each model can read, how much it can write, and what it accepts as input.

Metricopenai logoGPT-5.6 Terraanthropic logoClaude Sonnet 5
Context window1.05M tokens1M tokens
Max output128K tokens128K tokens
Input typesFile, Image, TextFile, Image, Text
Output typesTextText
Reasoning effort levelsMax, Extra high, High, Medium, Low, NoneMax, Extra high, High, Medium, Low
Default reasoning effortMediumHigh
Release dateJuly 9, 2026June 30, 2026

Features

Supported features

API features available for each model.

Metricopenai logoGPT-5.6 Terraanthropic logoClaude Sonnet 5
Tool callingSupportedSupported
Structured outputsSupportedSupported
JSON modeSupportedSupported
ReasoningSupportedSupported
TemperatureNot supportedNot supported
Stop sequencesNot supportedSupported
Deterministic seedSupportedNot supported
Verbosity controlSupportedSupported

Our take

Claude Sonnet 5 is 1.1x cheaper for a typical chat. GPT-5.6 Terra scores higher on the Artificial Analysis Intelligence Index (42.1 vs 38.2). GPT-5.6 Terra has the larger context window (1.05M vs 1M tokens). The right pick depends on your workload, so the quickest way to settle it is to send the same prompt to both and compare.

FAQ

Frequently asked questions

Is GPT-5.6 Terra or Claude Sonnet 5 cheaper?

Claude Sonnet 5 is cheaper for a typical chat (2K input tokens and 500 output tokens). Claude Sonnet 5 costs $2 per 1M input tokens and $10 per 1M output tokens, while GPT-5.6 Terra costs $2 per 1M input tokens and $12 per 1M output tokens.

Which has a bigger context window, GPT-5.6 Terra or Claude Sonnet 5?

GPT-5.6 Terra supports up to 1.05M tokens of context, compared with 1M for Claude Sonnet 5.

Is GPT-5.6 Terra smarter than Claude Sonnet 5?

On the Artificial Analysis Intelligence Index, GPT-5.6 Terra scores 42.1 and Claude Sonnet 5 scores 38.2, putting GPT-5.6 Terra ahead. Benchmarks don't capture everything, so the best test is running your own prompts through both.

Can I use GPT-5.6 Terra and Claude Sonnet 5 at the same time?

Yes. Shortcut Chat sends one prompt to multiple models at once, so you can see GPT-5.6 Terra and Claude Sonnet 5 answer side by side and keep the better response.

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Why choose? Ask both.

Send one prompt to GPT-5.6 Terra and Claude Sonnet 5 at the same time. Compare the answers side by side and keep the best one.