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GPT-5.6 Sol API Pricing & Cost Calculator

GPT-5.6 Sol is OpenAI's flagship-tier play. Compared to GPT-5.6 Terra's list price ($2/$12), it costs 2x on input and ~1.7x on output - it only pays off when you actually need frontier reasoning.

GPT-5.6 Sol is OpenAI's premium reasoning tier in the 5.6 generation, alongside Terra (workhorse) and Luna (ultra-cheap). It's priced just under Claude Opus 5 at $4/$20.

By TechCompare · Updated

Input tokens
100,000
per request
Output tokens
5,000
per request
Volume
100 / monthly
Standard API

Calculator

Cost Comparison

Based on 100,000 input tokens (50% cached), 5,000 output tokens, and 100 requests.Prices are fetched live from OpenRouter and may include temporary promotional discounts not accounted for in our article and comparison figures.

Same 100,000 in / 5,000 out (50% cached) scenario, pre-loaded. Adjust tokens, caching, or swap models.
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How this is calculated

GPT-5.6 Sol is priced at $4.00 per million input tokens and $20.00 per million output tokens, OpenAI's current flagship-tier list rate. It supports a 90% prompt caching discount ($0.40 per million) and a 50% batch discount ($2.00 per million inputs, $10.00 per million outputs) via OpenAI's Batch API.

Verdict

GPT-5.6 Sol sits at $4/M input and $20/M output, with the 90% cache discount dropping input to $0.40/M and the 50% batch discount dropping both rows to $2/M input and $10/M output. The cost ratio against GPT-5.6 Terra at $2/$12 is 2x on input and ~1.7x on output, even after both discounts, so Sol earns back its premium only when its reasoning depth actually changes the outcome: hard math proofs, deep multi-step planning, complex agentic chains. For the bulk of production traffic, Terra is the right default and Sol becomes the top of the cascade.

More API Standalones scenarios

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GPT-5.4 Pricing
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Claude Opus 4.8 Pricing
Single-model claude-opus-4.8 cost estimate
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Frequently asked questions

Should I pick GPT-5.6 Sol or GPT-5.6 Terra?
Sol ($4/$20) for hard reasoning tasks, and Terra ($2/$12 list price, though OpenRouter sometimes shows temporary discounts) for high-volume everyday workloads. Sol's premium only earns its keep on the most demanding agentic chains where Terra's reasoning falls short.
How much does GPT-5.6 Sol cost per million output tokens?
GPT-5.6 Sol charges $20.00 per million output tokens at standard list pricing. With the 50% batch discount, that drops to $10.00 per million. The 90% prompt caching discount brings cached input to $0.40 per million, useful for cache-heavy frontier-tier agentic workloads.
How does GPT-5.6 Sol compare to Claude Opus 5?
Sol is cheaper on both rows: $4/M input and $20/M output versus Opus 5's $5/M and $25/M. So Sol wins on price outright. The decision rests on capability and ecosystem: Sol has 1.05M context (Opus 5 has 1M) and OpenAI's tooling ecosystem, while Opus 5 counters with Anthropic's agentic tool-use strengths.

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