MODEL VERSIONS ON THIS PAGE HAVE MOVED — CHECKED 8 OCTOBER 2026
Current line, with published API pricing per million tokens:
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OpenAI — GPT-6 Sol (paid ChatGPT), GPT-6 Luna ($0.10 / $0.50), GPT-6.1 Sol ($2.00 / $10.00), GPT-6 Astra
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Anthropic — Claude Opus 5.5, Sonnet 5.5 ($2.00 / $10.00), Haiku 5.5 ($0.10 / $0.50 below 100K), Fable 5.1
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xAI — Grok 4.3 ($1.25 / $2.50), Grok 4.7 ($2.00 / $6.00)
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Google — Gemini 3.5 Flash-Lite ($0.30 / $2.50), Gemini 3.8 Flash ($0.75 / $3.75 to 31 Dec), Gemini 4 Argon
The comparison below is kept because the reasoning still holds — how these tiers trade price against capability has not changed. The version numbers and prices have.
Current pricing table →
QUICK VERDICT — AUGUST 2026 (ACT BEFORE AUG 31)
● Sonnet 5: $2/$10/M now (→ $3/$15 Sept 1) · adaptive thinking · 128K output · best writing quality
● GPT-5.6 Terra: $2.50/$15/M · balanced · OpenAI ecosystem · DALL-E 4 in same plan
● Gemini 3.6 Flash: $1.50/$7.50/M · cheapest · 304 tokens/sec · 1M context · Search grounding
● Cheapest: Gemini 3.6 Flash (stays cheapest after Aug 31)
● Best writing: Claude Sonnet 5
● Best context window: Gemini 3.6 Flash (1M tokens vs 200K Sonnet / 128K Terra)
● Best for Google ecosystem: Gemini 3.6 Flash (Search grounding, Workspace, Vertex)
● Aug 31 action: Front-load Sonnet 5 batch work — 50% price increase from Sept 1
At the mid-tier price point (roughly $1.50-$3.00/M input), Claude Sonnet 5, GPT-5.6 Terra, and Gemini 3.6 Flash are the three primary options. Gemini 3.6 Flash is the cheapest at $1.50/M — but it adds the most ecosystem value, with Google Search grounding (live data in responses), a 1M token context window, audio and video multimodal input, and 304 tokens/sec output speed. Sonnet 5 is Anthropic's strongest writing and general-purpose model at this price level — the 128K output window, adaptive thinking, and best-in-class writing quality are its primary advantages. Terra is OpenAI's mid-tier: more capable than Luna, less capable than Sol, and sitting in the middle on price. It benefits from the OpenAI ecosystem (Codex, DALL-E 4, Realtime API) and is a natural choice for teams already on OpenAI infrastructure.
Sonnet 5 for: Best writing quality at this price tier. Long-form generation (128K output). Adaptive thinking for complex reasoning. Anthropic FLI C+ safety posture. Act before August 31 — price goes from $2 to $3/M, and the tokenizer change adds 10-35% more tokens on code.
Gemini 3.6 Flash for: Cheapest capable mid-tier at $1.50/M. Google Search grounding for live data without a separate API. 1M context for large document processing. Audio/video multimodal input. Google Workspace and Vertex AI integration. 304 tokens/sec fastest output.
GPT-5.6 Terra for: OpenAI ecosystem users who need more than Luna but not Sol's price. Balanced capability. Access to Codex, DALL-E 4, and Realtime API in the same platform. The natural mid-tier choice if you are building on OpenAI infrastructure.
Last updated August 2026. Aug 31 deadline: Sonnet 5 $2→$3/M. Related: Sonnet 5 vs Opus 5 routing → · Gemini Flash vs Sonnet 5 →