GPT-5.3 Codex vs GPT-6 Astra
Benchmarks, API Token Pricing, Context Window & Speed Comparison
Related topics (4)
Compare GPT-5.3 Codex by OpenAI against GPT-6 Astra by OpenAI across real-world coding, reasoning, token economics, and latency.
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GPT-5.3 Codex
Coding LeapA coding model optimised for repository edits, review and agentic software engineering.
$2.00 / 1M
$16.00 / 1M
400K tokens
79%
GPT-6 Astra
Autonomous OS AgentOpenAI's late-2026 flagship foundation model featuring native Computer-Use agents, dynamic UI orchestration, and deep STEM reasoning.
$10.00 / 1M
$50.00 / 1M
272K tokens
82.4%
Key Differences at a Glance
- GPT-5.3 Codex is 3.5x cheaper for API usage (input + output tokens combined).
- GPT-5.3 Codex has a larger context window (400K vs 272K tokens).
- GPT-5.3 Codex is faster at 122 tok/s vs 100 tok/s.
- GPT-6 Astra leads on SWE-bench coding (82.4% vs 79.0%).
| Feature | GPT-5.3 Codex | GPT-6 Astra |
|---|---|---|
Intelligence Index Composite reasoning & knowledge score (0-100) | 72 | 96 |
Provider | OpenAI | OpenAI |
Input Price Cost per million input tokens | $2.00 / 1M | $10.00 / 1M |
Output Price Cost per million output tokens | $16.00 / 1M | $50.00 / 1M |
Blended Price Weighted 7:2:1 cache:input:output per 1M | $2.14 / 1M | $7.70 / 1M |
Context Window Maximum input + output tokens | 400K tokens~600 A4 pages of text | 272K tokens~408 A4 pages of text |
Max Output Tokens Per single request | 128K | 128K |
Throughput Speed Tokens generated per second | 122 tok/s | 100 tok/s |
SWE-bench Verified Real-world software engineering | 79% | 82.4% |
GPQA Diamond Graduate-level reasoning | 79.2% | 80.9% |
Cached Input Price Prompt caching discount per 1M tokens | $0.20 / 1M | $1.00 / 1M |
Who Wins Where?
At-a-glance decision frameworkEmpirical Head-to-Head Benchmark Scores
Official evaluation metrics verified by independent third-party research labs.
Industry benchmark evaluating real-world GitHub issue resolution and multi-file debugging.
Challenging questions created by domain experts to test complex PhD-level reasoning.
Hardened reasoning and academic knowledge benchmark with reduced lucky-guess probability.
Crowdsourced human preference evaluation based on blind, head-to-head model battles.
Extremely difficult, closed-ended questions spanning the frontier of human expert knowledge.
Autonomous multi-step tasks executed inside a real command-line terminal environment.
Research-grade coding problems drawn from real scientific and numerical workloads.
Contamination-free competitive programming problems collected continuously over time.
American Invitational Mathematics Examination — multi-step Olympiad-level reasoning.
Accuracy when reasoning over very large inputs that fill the model context window.
Tokens emitted per second during active generation streaming.
Latency & Response Time
Time to first token (TTFT) and estimated end-to-end response time for a typical 500-token response.
Real-Time Interactive Token Cost Simulator
Adjust sliders to calculate projected monthly cloud API spending with prompt caching discounts.
GPT-5.3 Codex · Strengths & Key Advantages
- A clear step up in multi-file code reasoning
- Fewer hallucinated APIs than earlier Codex generations
- Strong at test-driven repair loops
- Strong at large-scale automated migrations
Considerations & Trade-offs
- Premium pricing for a code-only model
- Diminishing returns versus GPT-5.2 Codex on small tasks
GPT-6 Astra · Strengths & Key Advantages
- Flawless OS-level navigation and Computer-Use automation
- Seamless real-time multimodal voice and vision interactivity
- Dynamic Chain-of-Thought that self-adjusts depth based on query difficulty
- Huge 1M context window with instant prefix caching
Considerations & Trade-offs
- Strict safety filters can occasionally throttle complex penetration testing prompts
- Slightly higher reasoning latency on high-effort math queries
Token Use & Task Economics
Estimated cost and token consumption to complete one representative agentic task.
| Metric | GPT-5.3 Codex | GPT-6 Astra |
|---|---|---|
Cost per Task Estimated USD to finish one task | $2.60 | $2.15 |
Output Tokens / Task Tokens generated per task | 62K | 58K |
Reasoning Tokens / Task Thinking tokens burned per task | 36K | 32K |
Technical Specifications
Architecture, release timeline, capabilities, and modalities.
| Feature | GPT-5.3 Codex | GPT-6 Astra |
|---|---|---|
| Official API Model ID (SDK) | gpt-5-3-codex | gpt-6-astra |
| API Protocol | OpenAI Responses API & Chat Completions v1 | OpenAI Responses API & Chat Completions v1 |
| Release Date | 2026-02 | 2026-09 |
| Knowledge Cutoff | November 2025 | June 2026 |
| Architecture | Code-specialised unified reasoning model | Omni-Adaptive Autoregressive with Dynamic CoT |
| Parameters | Confidential | Confidential |
| Enterprise Rate Limits (RPM / TPM) | 10,000 – 30,000 RPM (Tier 5 Enterprise) · 800,000 – 2,000,000 TPM | 10,000 – 30,000 RPM (Tier 5 Enterprise) · 800,000 – 2,000,000 TPM |
| Long-Context Tier (>128K/200K) | Flat rate ($2/1M in) across full 400K window | Flat rate ($10/1M in) across full 272K window |
| Prompt Cache Policy & TTL | Automatic prefix caching at $0.2/1M (no extra cache-write fee) | Automatic prefix caching at $1/1M (no extra cache-write fee) |
| Computer Use / GUI Agent | Supported (Screen coordinate grounding, browser & desktop GUI action loops) | Supported (Screen coordinate grounding, browser & desktop GUI action loops) |
| MCP & Parallel Tool Calling | Native MCP Client/Server ready · Parallel function calling · 100% Strict JSON Schema | Native MCP Client/Server ready · Parallel function calling · 100% Strict JSON Schema |
| Web Search Grounding & Sandbox | Native Web Search tool + Hosted Code Interpreter & File Search RAG | Native Web Search tool + Hosted Code Interpreter & File Search RAG |
| Official Fine-Tuning Support | Supervised Fine-Tuning (SFT), Direct Preference (DPO) & Reinforcement Fine-Tuning (RFT) | Supervised Fine-Tuning (SFT), Direct Preference (DPO) & Reinforcement Fine-Tuning (RFT) |
| Multimodal Token Billing | Text BPE (~4 chars/token) · Vision (~258–765 tokens per image tile) | Text BPE (~4 chars/token) · Vision (~258–765 tokens per image tile) · Audio (~25–32 tokens/sec) |
| Quantization & Min GPU VRAM | Cloud-Hosted Proprietary (FP8 / BF16 Tensor Core Cluster) · Zero Local VRAM Required (100% Serverless Cloud API) | Cloud-Hosted Proprietary (FP8 / BF16 Tensor Core Cluster) · Zero Local VRAM Required (100% Serverless Cloud API) |
| Safety & Frontier Classification | OpenAI Preparedness Framework Audited & System Card Published | OpenAI Preparedness Framework Audited & System Card Published |
| Enterprise Compliance (ZDR/HIPAA/SOC2) | SOC2 Type II · GDPR · Zero Data Retention (ZDR) & HIPAA BAA Available on Enterprise Tier | SOC2 Type II · GDPR · Zero Data Retention (ZDR) & HIPAA BAA Available on Enterprise Tier |
| Input Modalities | text, vision | text, vision, audio |
| Output Modalities | text | text, audio |
GPT-5.3 Codex vs GPT-6 Astra: Quick Answers
Which is more intelligent, GPT-5.3 Codex or GPT-6 Astra?
GPT-6 Astra is more intelligent. It scores 96 compared with 72 on the composite Intelligence Index.
Which model is faster?
GPT-5.3 Codex is faster, generating 122 tokens per second compared with 100 tokens per second.
Which model is cheaper to run?
GPT-5.3 Codex is cheaper at $2.14 per 1M tokens blended, compared with $7.70 (7:2:1 cache:input:output ratio).
Which model has lower latency?
GPT-6 Astra has lower latency, with a time to first token of 0.95s compared with 1.23s.
Which model has a larger context window?
GPT-5.3 Codex has a larger context window, supporting 400K tokens compared with 272K tokens.
Verdict
Choose GPT-5.3 Codex for teams whose default workflow is agent-driven development, or choose GPT-6 Astra for autonomous browser/computer workflows, real-time voice agents, and high-difficulty mathematical reasoning.
Frequently asked questions
Which is cheaper: GPT-5.3 Codex or GPT-6 Astra?+
GPT-5.3 Codex costs $2/1M input and $16/1M output tokens, while GPT-6 Astra costs $10/1M input and $50/1M output tokens.
Which model has a larger context window: GPT-5.3 Codex or GPT-6 Astra?+
GPT-5.3 Codex supports 400K tokens whereas GPT-6 Astra supports 272K tokens.
Understand key metrics like context window, token pricing, reasoning mode, and SWE-bench scores in our comprehensive AI glossary.
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Benchmark scores, token prices, and rate limits evolve rapidly as AI labs release model updates. Always verify current specifications and pricing on the official provider documentation.
Sources: OpenAI & OpenAI Official Documentation