OpenAI · AI model
GPT-6 Luna
Lowest-priced GPT-6 model, described by OpenAI as its most efficient model for focused, high-volume tasks. Text and image input, text output, 1.05M-token context window, reasoning effort from none to max.
Last verified Available 11 sources
Key specs
- Provider
- OpenAI
- Family
- GPT-6
- API identifier
- gpt-6-luna
- Availability
- Available
- Release date
- 2026-09-22
- License
- Proprietary
- Context window
- 1,050,000 tokens
- Max output
- 128,000 tokens
- Knowledge cutoff
- May 2026
- API access
- Yes
- Consumer app
- Yes
Capabilities
Inputs
- Text input Yes
- Image input Yes
- Audio input No Model page marks audio as not supported
- Video input No Model page marks video as not supported
- File input Yes File inputs guide: PDFs (text plus page images on vision-capable models such as gpt-4o and later), documents, presentations and spreadsheets as file inputs in the Responses API; Chat Completions accepts PDF only
Outputs
- Text output Yes
- Image output No Text is the only output modality; images can be created through the Responses API image_generation tool, which uses a GPT Image model
- Audio output No Model page marks audio as not supported; text is the only output modality
Features
- Reasoning Optional reasoning.effort supports none, low, medium (default), high, xhigh and max
- Tool calling Yes Responses API supports built-in tools and function calling; Chat Completions supports function calling only with reasoning_effort none (model page and 'Using GPT-6' guide)
- Web search Yes Web search listed as a supported feature and Responses API tool on the model page; tool calls are billed separately ($10 per 1K calls plus search content tokens at model rates, pricing page)
"Unknown" means we have not verified this capability yet; it does not mean the model lacks it.
Pricing
Estimate your monthly cost →| Dimension | Tier | Price | Since | Verified | Source |
|---|---|---|---|---|---|
| Input tokens | base | $0.10 per 1M tokens | 2026-10-12 | 2026-10-25 | Pricing | OpenAI API Standard processing, prompts up to 272K input tokens (pricing page, Standard table) |
| > 272K input tokens (≥ 272,001 input tokens) | $0.20 per 1M tokens | 2026-10-12 | 2026-10-25 | Pricing | OpenAI API Standard processing, long-context column of the pricing page Standard table; the model page states that prompts with more than 272K input tokens are priced at 2x input and cache rates and 1.5x output for the full request | |
| Cached input tokens | base | $0.01 per 1M tokens | 2026-10-12 | 2026-10-25 | Pricing | OpenAI API Standard processing, prompts up to 272K input tokens (pricing page, Standard table) |
| > 272K input tokens (≥ 272,001 input tokens) | $0.02 per 1M tokens | 2026-10-12 | 2026-10-25 | Pricing | OpenAI API Standard processing, long-context column of the pricing page Standard table; the model page states that prompts with more than 272K input tokens are priced at 2x input and cache rates and 1.5x output for the full request | |
| Cache writes | base | $0.125 per 1M tokens | 2026-10-12 | 2026-10-25 | Pricing | OpenAI API 30-minute cache write (default prompt_cache_options.ttl), billed at 1.25x the uncached input rate; Standard processing, prompts up to 272K input tokens (pricing page, Standard table) |
| > 272K input tokens (≥ 272,001 input tokens) | $0.25 per 1M tokens | 2026-10-12 | 2026-10-25 | Pricing | OpenAI API 30-minute cache write, long-context column of the pricing page Standard table (prompts with more than 272K input tokens are priced at 2x input and cache rates for the full request) | |
| Output tokens | base | $0.50 per 1M tokens | 2026-10-12 | 2026-10-25 | Pricing | OpenAI API Standard processing, prompts up to 272K input tokens (pricing page, Standard table) |
| > 272K input tokens (≥ 272,001 input tokens) | $0.75 per 1M tokens | 2026-10-12 | 2026-10-25 | Pricing | OpenAI API Standard processing, long-context column of the pricing page Standard table; the model page states that prompts with more than 272K input tokens are priced at 2x input and cache rates and 1.5x output for the full request | |
| Batch input tokens | base | $0.05 per 1M tokens | 2026-10-12 | 2026-10-25 | Pricing | OpenAI API Batch API, prompts up to 272K input tokens (pricing page, Batch table); the model page states Batch is priced at 50% of Standard rates |
| > 272K input tokens (≥ 272,001 input tokens) | $0.10 per 1M tokens | 2026-10-12 | 2026-10-25 | Pricing | OpenAI API Batch API, long-context column of the pricing page Batch table (prompts with more than 272K input tokens); the model page states Batch is priced at 50% of Standard rates | |
| Batch output tokens | base | $0.25 per 1M tokens | 2026-10-12 | 2026-10-25 | Pricing | OpenAI API Batch API, prompts up to 272K input tokens (pricing page, Batch table); the model page states Batch is priced at 50% of Standard rates |
| > 272K input tokens (≥ 272,001 input tokens) | $0.375 per 1M tokens | 2026-10-12 | 2026-10-25 | Pricing | OpenAI API Batch API, long-context column of the pricing page Batch table (prompts with more than 272K input tokens); the model page states Batch is priced at 50% of Standard rates | |
| Tool and search requests | base | $10.00 per 1,000 requests | 2026-10-12 | 2026-10-25 | Pricing | OpenAI API Web search tool (pricing page, Tools table: all models): per 1,000 calls, plus search content tokens billed at model rates |
| Other | 12-hour cache writes | $0.25 per 1M units | 2026-10-25 | 2026-10-25 | Pricing | OpenAI API 12-hour cache write (prompt_cache_options.ttl "12h", Responses API, added 2026-10-20), billed at 2.5x the uncached input rate; Standard, prompts up to 272K input tokens (pricing page) |
| 12-hour cache writes, > 272K input tokens (≥ 272,001 input tokens) | $0.50 per 1M units | 2026-10-25 | 2026-10-25 | Pricing | OpenAI API 12-hour cache write, long-context column of the pricing page Standard table (prompts with more than 272K input tokens) |
Prices are shown in the currency the provider publishes; we never convert currencies.
Price history (15 entries)
| Dimension | Tier | Price | From | Until |
|---|---|---|---|---|
| Input tokens | base | $0.10 per 1M tokens | 2026-10-12 | current |
| Input tokens | > 272K input tokens (≥ 272,001 input tokens) | $0.20 per 1M tokens | 2026-10-12 | current |
| Cached input tokens | base | $0.01 per 1M tokens | 2026-10-12 | current |
| Cached input tokens | > 272K input tokens (≥ 272,001 input tokens) | $0.02 per 1M tokens | 2026-10-12 | current |
| Cache writes | base | $0.125 per 1M tokens | 2026-10-12 | current |
| Cache writes | > 272K input tokens (≥ 272,001 input tokens) | $0.25 per 1M tokens | 2026-10-12 | current |
| Output tokens | base | $0.50 per 1M tokens | 2026-10-12 | current |
| Output tokens | > 272K input tokens (≥ 272,001 input tokens) | $0.75 per 1M tokens | 2026-10-12 | current |
| Batch input tokens | base | $0.05 per 1M tokens | 2026-10-12 | current |
| Batch input tokens | > 272K input tokens (≥ 272,001 input tokens) | $0.10 per 1M tokens | 2026-10-12 | current |
| Batch output tokens | base | $0.25 per 1M tokens | 2026-10-12 | current |
| Batch output tokens | > 272K input tokens (≥ 272,001 input tokens) | $0.375 per 1M tokens | 2026-10-12 | current |
| Tool and search requests | base | $10.00 per 1,000 requests | 2026-10-12 | current |
| Other | 12-hour cache writes | $0.25 per 1M units | 2026-10-25 | current |
| Other | 12-hour cache writes, > 272K input tokens (≥ 272,001 input tokens) | $0.50 per 1M units | 2026-10-25 | current |
Benchmarks
| Benchmark | Setting | Score | Reported by | Measured | Verified | Source |
|---|---|---|---|---|---|---|
| AutomationBench % tasks completed correctly, higher is better | v1.0.6; high effort | 14.5 % | Self-reported | — | 2026-10-25 | Introducing GPT-6 Sol and Luna | OpenAI |
| v1.0.6; high effort | 14.46 % | Third party | — | 2026-10-25 | AutomationBench AI benchmark leaderboard (Zapier) | |
| v1.0.6; low effort | 1.2 % | Self-reported | — | 2026-10-25 | Introducing GPT-6 Sol and Luna | OpenAI | |
| v1.0.6; low effort | 1.22 % | Third party | — | 2026-10-25 | AutomationBench AI benchmark leaderboard (Zapier) | |
| v1.0.6; max effort | 20.7 % | Self-reported | — | 2026-10-25 | Introducing GPT-6 Sol and Luna | OpenAI | |
| v1.0.6; max effort | 20.7 % | Third party | — | 2026-10-25 | AutomationBench AI benchmark leaderboard (Zapier) | |
| v1.0.6; medium effort | 9.4 % | Self-reported | — | 2026-10-25 | Introducing GPT-6 Sol and Luna | OpenAI | |
| v1.0.6; medium effort | 9.44 % | Third party | — | 2026-10-25 | AutomationBench AI benchmark leaderboard (Zapier) | |
| v1.0.6; none effort | 0.3 % | Third party | — | 2026-10-25 | AutomationBench AI benchmark leaderboard (Zapier) | |
| v1.0.6; xhigh effort | 12.6 % | Self-reported | — | 2026-10-25 | Introducing GPT-6 Sol and Luna | OpenAI | |
| v1.0.6; xhigh effort | 12.63 % | Third party | — | 2026-10-25 | AutomationBench AI benchmark leaderboard (Zapier) | |
| DeepSWE v1.1 % resolved (pass@1), higher is better | v1.1; high effort | 59.3 % | Self-reported | — | 2026-10-25 | Introducing GPT-6 Sol and Luna | OpenAI |
| v1.1; low effort | 2.4 % | Self-reported | — | 2026-10-25 | Introducing GPT-6 Sol and Luna | OpenAI | |
| v1.1; max effort | 66.6 % | Self-reported | — | 2026-10-25 | Introducing GPT-6 Sol and Luna | OpenAI | |
| v1.1; medium effort | 44.5 % | Self-reported | — | 2026-10-25 | Introducing GPT-6 Sol and Luna | OpenAI | |
| v1.1; xhigh effort | 61.3 % | Self-reported | — | 2026-10-25 | Introducing GPT-6 Sol and Luna | OpenAI | |
| FrontierMath Tiers 1-3 (v2) accuracy %, higher is better | max effort; Epoch harness (Python tool) | 78.9 % | Third party | — | 2026-10-25 | FrontierMath Tiers 1-3 (v2) leaderboard (Epoch AI) |
| GDPval-AA v2.1 Elo, higher is better | high effort | 1,343 Elo | Third party | 2026-10-25 | 2026-10-25 | GDPval-AA v2.1 Leaderboard (Artificial Analysis) |
| low effort | 1,032 Elo | Third party | 2026-10-25 | 2026-10-25 | GDPval-AA v2.1 Leaderboard (Artificial Analysis) | |
| max effort | 1,433 Elo | Third party | 2026-10-25 | 2026-10-25 | GDPval-AA v2.1 Leaderboard (Artificial Analysis) | |
| medium effort | 1,263 Elo | Third party | 2026-10-25 | 2026-10-25 | GDPval-AA v2.1 Leaderboard (Artificial Analysis) | |
| non-reasoning | 1,045 Elo | Third party | 2026-10-25 | 2026-10-25 | GDPval-AA v2.1 Leaderboard (Artificial Analysis) | |
| xhigh effort | 1,363 Elo | Third party | 2026-10-25 | 2026-10-25 | GDPval-AA v2.1 Leaderboard (Artificial Analysis) | |
| OSWorld 2.0 % tasks completed, higher is better | v2026.08.08, offline set, partial score; high effort | 41.4 % | Self-reported | — | 2026-10-25 | Introducing GPT-6 Sol and Luna | OpenAI |
| v2026.08.08, offline set, partial score; low effort | 8.3 % | Self-reported | — | 2026-10-25 | Introducing GPT-6 Sol and Luna | OpenAI | |
| v2026.08.08, offline set, partial score; max effort | 52.7 % | Self-reported | — | 2026-10-25 | Introducing GPT-6 Sol and Luna | OpenAI | |
| v2026.08.08, offline set, partial score; medium effort | 31.5 % | Self-reported | — | 2026-10-25 | Introducing GPT-6 Sol and Luna | OpenAI | |
| v2026.08.08, offline set, partial score; xhigh effort | 46.7 % | Self-reported | — | 2026-10-25 | Introducing GPT-6 Sol and Luna | OpenAI | |
| Terminal-Bench 4.0 % tasks resolved, higher is better | max effort; Codex harness | 16.4 % | Third party | — | 2026-10-25 | Terminal-Bench 4.0 leaderboard (Harbor Hub) |
| Text Arena Arena score, higher is better | Overall, style control on; max effort | 1,442 | Third party | 2026-10-23 | 2026-10-25 | Text Arena leaderboard (Arena) |
Leaderboard versions (for example 1.0.5 and 1.0.6) are not comparable. Some results use fallback routing for refused steps: for "Claude Fable 5.1 (with Opus 5 Fallback)", Opus 5 handled 260 of 657 tasks. Artificial Analysis runs a separate leaderboard, AutomationBench-AA, which uses a guardrail-adjusted metric; its scores are not comparable with Zapier's. The partial_credit metric is for diagnostics only. The leaderboard shows no per-row evaluation dates.
The official leaderboard uses mini-swe-agent for all models and shows whole-number percentages with margins of about ±1 to ±6 points. Providers often report scores from their own scaffolds or effort settings; DeepSeek reports 65.5% to 74.2% for the same model depending on the scaffold. DeepSWE v1 scores are not comparable with v1.1. With only 113 tasks, small differences are within noise.
FrontierMath was developed with funding from OpenAI, which has exclusive access to a subset of the problems. Scores from v1 and from Tier 4 (a separate 43-problem expansion set) are not comparable with Tiers 1-3 (v2). The best models score about 94%, so the benchmark separates mid-size models better than it separates frontier models. Epoch's numbers come from its own harness (Python tool, 1M-token limit), which can differ from providers' internal setups. Margins are about ±1.4 to ±2.6 points.
Elo is a relative rating: values change as models are added and the scale is re-anchored, so always store the date a rating was read. For example, Anthropic's launch page gives 1846 for Claude Opus 5.5, while the leaderboard on 2026-10-12 shows 1866 (Max, Default Fallback). Earlier versions (Google cites "GDPVal-AA v2") are not comparable. Judging is done by an LLM, not by human experts. Anthropic models are listed with "Default Fallback", meaning refused steps are routed to a fallback model. AA-Briefcase and GDP.pdf are separate evaluations.
Numbers are only comparable when release, task set (full or offline), metric (binary or partial), step budget (150, 300 or 500) and agent approach (standard or batch tool calls) all match. Providers usually quote partial scores, which are much higher than binary completion. Claude Opus 5 at max effort on v2.1 scores 44.33% binary and 77.67% partial. The verified leaderboard is run by the maintainers and covers few current models, so most numbers are self-reported. The original OSWorld and OSWorld-Verified (369 tasks) are a different benchmark and are not recorded here.
Scores depend heavily on the agent harness (for example Claude Code, Codex, Grok Build or mini-SWE-agent) and on the reasoning effort, so the same model appears several times on the leaderboard. Leaderboard rows are often submitted by the organisation that builds the agent. Providers' own runs can differ from the leaderboard: Anthropic reports 66.4% for Claude Opus 5.5 at max effort, while the leaderboard lists 64.8% ± 3.1%. Versions 2.0, 2.1 and 3.0 and Artificial Analysis' "Terminal-Bench Hard" use different task sets and are not comparable with 4.0. Margins are about ±3 points.
Scores measure voter preference, which can be influenced by answer style and length. The leaderboard offers a style-control adjustment, so record which view was used. Scores shift with every update, so a value is only meaningful together with its leaderboard date. Entries marked "Preliminary" or with few votes have wide confidence intervals. The same model can appear several times with different reasoning-effort suffixes (for example -high or -max). Category views (Coding, Math, Creative Writing and others) are different rankings from Overall.
One row per result, without rank numbers: each result was measured under its own setting (effort level, harness, tools, test version), as stated by the source, and scores compare only within the same setting. Self-reported results come from the provider and have not been reproduced independently.
Rankings
- #2 of 42 in Best AI API as of 2026-10-26
- #6 of 26 in Best AI for students as of 2026-10-26
- #7 of 39 in Best AI for business as of 2026-10-26
- #7 of 20 in Best AI for coding as of 2026-10-27
Derived from our published ranking snapshots; each ranking explains its criteria and weights.
Compare GPT-6 Luna
Guides
- AI token pricing explained: input, output, cached and batch rates
- Reasoning models explained: thinking modes, effort and cost
- Multimodal AI explained: image, audio, video and file inputs, and what they cost
- Context windows explained: limits, long-context pricing and recall
- How to choose an AI model: a practical decision framework
About GPT-6 Luna
GPT-6 Luna is described by OpenAI as its most efficient model for focused, high-volume tasks. It accepts text and image input, produces text output and supports reasoning effort levels none, low, medium (default), high, xhigh and max. It is available through the Responses, Chat Completions and Batch endpoints. In ChatGPT it is available in ChatGPT Work and Codex, and the October 7, 2026 release notes state that Free and Go use GPT-6 Luna in Chat.
Strengths and weaknesses
Strengths
- Lowest price in the GPT-6 line-up: $0.10 input / $0.50 output per 1M tokens (Standard, up to 272K input tokens)
- 1,050,000-token context window and 128,000 max output tokens
- Reasoning can be switched off (
none) or raised up to max - Latest knowledge cutoff among the GPT-6 models (May 18, 2026)
Weaknesses
- Function calling in Chat Completions works only with reasoning_effort
none(Responses API required for reasoning with tools) - No audio or video input; text output only
Sources
- GPT-6 Luna Model | OpenAI API
- Changelog | OpenAI API
- File inputs | OpenAI API
- Using GPT-6 | OpenAI API
- Pricing | OpenAI API
- Introducing GPT-6 Sol and Luna | OpenAI
- Terminal-Bench 4.0 leaderboard (Harbor Hub)
- FrontierMath Tiers 1-3 (v2) leaderboard (Epoch AI)
- GDPval-AA v2.1 Leaderboard (Artificial Analysis)
- AutomationBench AI benchmark leaderboard (Zapier)
- Text Arena leaderboard (Arena)
Last verified Page updated 2026-10-27