GPT-5.6 Terra API Pricing & Cost Calculator

Terra is the GPT-5.6 default for production. Stronger reasoning than Gemini 3.6 Flash at a higher list price, and the 90% cache discount keeps long-context loops surprisingly cheap.

GPT-5.6 Terra is the workhorse tier of OpenAI's 5.6 lineup, sitting between GPT-5.6 Sol (flagship) and GPT-5.6 Luna (ultra-cheap) for high-volume production workloads.

By TechCompare · Updated

Input tokens
100,000
50% cached
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.

How this is calculated

GPT-5.6 Terra is priced at $2.00 per million input tokens and $12.00 per million output tokens at OpenAI's published list price, with a 90% prompt caching discount ($0.20 per million). That puts it 2.5x below GPT-5.6 Sol on input and 10x above GPT-5.6 Luna on input. OpenAI's standard 50% batch discount applies via the Batch API ($1.00 per million inputs, $6.00 per million outputs). Note: OpenRouter currently runs a limited-time 50% discount that can show Terra at $1/$6 in live calculators.

Verdict

Terra is the GPT-5.6 default for production. Stronger reasoning than Gemini 3.6 Flash at a higher list price, and the 90% cache discount keeps long-context loops surprisingly cheap.

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Frequently asked questions

Why pick GPT-5.6 Terra over GPT-5.6 Luna?
Terra ($2/$12 list price) is 10x more expensive than Luna ($0.20/$1.20 list price) per token but produces meaningfully stronger reasoning. Pick Terra when quality matters and reserve Luna for high-volume classification, extraction, or simple completions. OpenRouter sometimes shows Terra at a temporary $1/$6 discounted rate in live calculators.