API cost decision in 10 seconds

GPT-5.3-Codex vs GPT-5.1-Codex-Max

Pick GPT-5.1-Codex-Max when budget is the priority.

Pricing data updated: 2026-05-26T11:08:00Z Prices normalized to USD per 1M tokens Sample workload: 1M input + 500K output

Budget verdict

Pick GPT-5.1-Codex-Max when budget is the priority.

On the standard 1M input plus 500K output workload, GPT-5.1-Codex-Max is estimated at $6.25 vs $8.75 for GPT-5.3-Codex, saving $2.5 (28.6% lower).

Cost-first pickGPT-5.1-Codex-Max

Context-first pickBoth models

Sample savings$2.528.6%

10x traffic gap$25

The reported context window is tied, so cost and provider fit carry more weight. At 10x that traffic, the same price gap is about $25. Use the calculator below to replace the sample workload with your own token volume.

Cost sensitivity

Workload Sensitivity

Same prices, different token mixes.

GPT-5.1-Codex-Max stays cheaper across input-heavy, balanced, and output-heavy sample workloads.

Workload shape	Token mix	Better pick	GPT-5.3-Codex	GPT-5.1-Codex-Max
Input-heavy / RAG	5M input + 500K output	GPT-5.1-Codex-Max	$15.75	$11.25
Balanced workload	1M input + 1M output	GPT-5.1-Codex-Max	$15.75	$11.25
Output-heavy chatbot	1M input + 5M output	GPT-5.1-Codex-Max	$71.75	$51.25

Cheaper input GPT-5.1-Codex-Max $1.75 vs $1.25 / 1M

GPT-5.1-Codex-Max is $0.5 cheaper per 1M input tokens (28.6% lower; 1.4x difference).

Cheaper output GPT-5.1-Codex-Max $14 vs $10 / 1M

GPT-5.1-Codex-Max is $4 cheaper per 1M output tokens (28.6% lower; 1.4x difference).

Larger context Tie 400K vs 400K

Both models report the same context window at 400K tokens.

Sample workload GPT-5.1-Codex-Max $8.75 vs $6.25

GPT-5.1-Codex-Max is $2.5 cheaper on the standard workload (28.6% lower).

Estimate your workload cost

Your Workload Cost

Prices are normalized to USD per 1M tokens.

Monthly input tokens Monthly output tokens

GPT-5.3-Codex Calculating… Estimated API cost

GPT-5.1-Codex-Max Calculating… Estimated API cost

Cheaper for this workload Calculating… Difference: calculating…

This estimate uses normalized public API pricing per 1M tokens. It is a planning aid, not a billing quote. Verify provider pricing, limits, and terms before production use.

Quick Decision

Verdict

GPT-5.1-Codex-Max has the lower input price; GPT-5.1-Codex-Max has the lower output price; both models report the same context window. For the 1M input plus 500K output sample, GPT-5.1-Codex-Max is cheaper for the standard workload.

For a 1M input token plus 500K output token workload, the estimated API cost is $8.75 for GPT-5.3-Codex and $6.25 for GPT-5.1-Codex-Max.

Best Fit

Choose GPT-5.3-Codex when its provider, model quality, latency, or availability is more important than the numeric price/context winner.

Choose GPT-5.1-Codex-Max when you care most about lower input-token price, and lower output-token price.

Decision Notes

On the standard 1M input plus 500K output workload, GPT-5.1-Codex-Max is estimated at $6.25 vs $8.75 for GPT-5.3-Codex, saving $2.5 (28.6% lower).
GPT-5.1-Codex-Max is $2.5 cheaper on the standard workload (28.6% lower).
GPT-5.1-Codex-Max is $0.5 cheaper per 1M input tokens (28.6% lower; 1.4x difference).
GPT-5.1-Codex-Max is $4 cheaper per 1M output tokens (28.6% lower; 1.4x difference).
Both models report the same context window at 400K tokens.

Head-to-Head Specs

Feature	GPT-5.3-Codex (OpenAI)	GPT-5.1-Codex-Max (OpenAI)
Input Price prompt tokens per 1M	$1.75	$1.25
Completion Price per 1M tokens	$14	$10
Sample Workload Cost 1M input + 500K output	$8.75	$6.25
Context Window	400K	400K
Release Date	2026-02-24	2025-12-04

Use-Case Decision Matrix

Use case	Better pick	Why
Budget-constrained production	GPT-5.1-Codex-Max	On the standard 1M input plus 500K output workload, GPT-5.1-Codex-Max is estimated at $6.25 vs $8.75 for GPT-5.3-Codex, saving $2.5 (28.6% lower).
High-volume input processing	GPT-5.1-Codex-Max	Lower prompt-token price matters most when prompts, retrieved passages, or documents dominate the bill.
Long responses and chatbots	GPT-5.1-Codex-Max	Lower output-token price matters most when assistants generate many completion tokens.
RAG or long-document work	Tie	A larger context window leaves more room for retrieved passages, conversation history, or source files.

Related Alternatives

Same-provider lower-cost swaps

gpt-oss-120b (free) can replace GPT-5.3-Codex when lower sample workload cost matters most: $0.
gpt-oss-20b (free) can replace GPT-5.3-Codex when lower sample workload cost matters most: $0.
gpt-oss-20b can replace GPT-5.3-Codex when lower sample workload cost matters most: $0.1.
gpt-oss-120b can replace GPT-5.3-Codex when lower sample workload cost matters most: $0.13.

Larger context near this budget

Llama 4 Scout offers 10M context with $0.23 sample workload cost.
Grok 4.20 Multi-Agent offers 2M context with $5 sample workload cost.
Grok 4.20 offers 2M context with $2.5 sample workload cost.
GPT-5.4 offers 1.05M context with $10 sample workload cost.

Popular competitors

No popular competitor is currently available.

Cheaper alternatives

Review low-cost models sorted by a standard 1M input plus 500K output workload.

Open cheapest models

Larger context alternatives

Find models with larger context windows for RAG, long documents, and codebase review.

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Provider catalogs

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OpenAI catalog

Review all tracked OpenAI models before deciding whether this matchup is the right shortlist.

Open OpenAI models

GPT-5.3-Codex

GPT-5.3-Codex is OpenAI’s most advanced agentic coding model, combining the frontier software engineering performance of GPT-5.2-Codex with the broader reasoning and professional knowledge capabilities of GPT-5.2. It achieves state-of-the-art results...

GPT-5.1-Codex-Max

GPT-5.1-Codex-Max is OpenAI’s latest agentic coding model, designed for long-running, high-context software development tasks. It is based on an updated version of the 5.1 reasoning stack and trained on agentic...