Head-to-Head Model Pricing & Benchmark Breakdown
GPT-5.3 Codex vs Claude Sonnet 5: Frontier Software Engineering Showdown
Evaluate developer token pricing, repository-level refactoring, and SWE-bench accuracy.
Adjust Your Custom Token Workload
Monthly Requests60k
Input Tokens / Req5000
Output Tokens / Req900
Prompt Cache %60%
Claude Sonnet 5 is 21.9% More Cost-Effective
Saves $228.75 per month ($2,745.00/yr) at this volume.
Annualized Savings$2,745.00
OpenAI
GPT-5.3 Codex
Total Monthly Cost
$1,044.75 / month
$17.41 per 1,000 requestsInput Tokens / 1M:$1.75
Cached Input / 1M:$0.438
Output Tokens / 1M:$14.00
Context Window:400k
Inference Speed:~95 TPS
Anthropic
Most EconomicalClaude Sonnet 5
Total Monthly Cost
$816.00 / month
$13.60 per 1,000 requestsInput Tokens / 1M:$2.00
Cached Input / 1M:$0.200
Output Tokens / 1M:$10.00
Context Window:1M
Inference Speed:~90 TPS
The Verdict: Which Model Wins on Cost & ROI?
GPT-5.3 Codex is slightly cheaper on input ($1.75 vs $2.00) and scores 97.8% on coding benchmarks, while Claude Sonnet 5 offers cheaper output tokens ($10.00 vs $14.00), 1M context (vs 400k), and a 90% prompt caching discount.
Key Architectural & Economic Differences
- GPT-5.3 Codex input is 12.5% cheaper ($1.75/1M vs $2.00/1M).
- Claude Sonnet 5 output tokens are 28% cheaper ($10.00/1M vs $14.00/1M).
- Claude Sonnet 5 supports 1,000,000 tokens context vs 400,000 on Codex.
- Claude Sonnet 5 offers 90% prompt caching discount ($0.20/1M cached).
When to Choose GPT-5.3 Codex
- • In-IDE automated unit test writing and granular function autocompletion
- • Workloads optimized for 400k context codebuffers
When to Choose Claude Sonnet 5
- • Full-repository autonomous agent refactoring requiring 1M context
- • Heavily cached multi-turn PR review and debugging loops
Detailed Spec & Pricing Comparison Table
| Specification / Metric | GPT-5.3 Codex (OpenAI) | Claude Sonnet 5 (Anthropic) | Advantage |
|---|---|---|---|
| Input Price / 1M Tokens | $1.75 | $2.00 | GPT-5.3 Codex |
| Cached Input Price / 1M | $0.438 (75%) | $0.200 (90%) | Claude Sonnet 5 |
| Output Price / 1M Tokens | $14.00 | $10.00 | Claude Sonnet 5 |
| Context Window | 400k | 1M | Claude Sonnet 5 |
| Inference Speed (Tokens/Sec) | ~95 TPS | ~90 TPS | GPT-5.3 Codex |
| MMLU Benchmark Score | 92% | 93.8% | Claude Sonnet 5 |
Frequently Asked Questions
Claude Sonnet 5 is superior for whole-repository analysis thanks to its 1,000,000 token context window and 90% prompt caching discount, allowing entire codebases to be ingested cost-effectively.
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