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Comparison · 2 models · Updated Oct 4, 2026

GPT-5.3 Codex vs GPT-5.4 mini

Too close to call on our weighted score (GPT-5.3 Codex 64, GPT-5.4 mini 63). The right pick depends on what you value most.

  1. OpenAI

    GPT-5.3 Codex

    Released Feb 5, 2026

    64/100
    • ECI156.8
    • Price$1.75 / $14.00
    • Context400K
    Full specs Remove GPT-5.3 Codex

  2. OpenAI

    GPT-5.4 mini

    Released Mar 17, 2026

    63/100
    • ECI148.8
    • Price$0.75 / $4.50
    • Context400K
    Full specs Remove GPT-5.4 mini

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01 — Verdict

Too close to call

It is close. Our weighted score puts them within 1 points (GPT-5.3 Codex 64/100, GPT-5.4 mini 63/100), so choose by what matters most for your work: GPT-5.3 Codex for raw capability and GPT-5.4 mini on price. The score weighs capability 50%, price 25%, inputs & features 15%, context window 10%.

  • CapabilityGPT-5.3 CodexCapabilities Index (ECI): GPT-5.3 Codex 156.8 · GPT-5.4 mini 148.8
  • Lowest priceGPT-5.4 miniGPT-5.4 mini $1.69 · GPT-5.3 Codex $4.81 per 1M tokens (3:1 blend)
  • Longest contextAbout the sameGPT-5.3 Codex 400,000 · GPT-5.4 mini 400,000 tokens
  • Widest inputsGPT-5.3 CodexGPT-5.3 Codex: Text, Images, PDFs · GPT-5.4 mini: Text, Images
  • Self-hostingNo open weightsBoth are available only through APIs
How the score is built
MeasureWeightGPT-5.3 CodexGPT-5.4 mini
CapabilityCapabilities Index (ECI)50%8777
Price25%1839
Inputs & features15%8070
Context window10%4444
Overall100%64/10063/100
02 — Side by side

Every spec in one table

Highlighted cells lead their row. Dashes mean the data is not published.

GPT-5.3 Codex vs GPT-5.4 mini specifications side by side
SpecificationGPT-5.3 CodexOpenAIGPT-5.4 miniOpenAI
Capability
Capabilities Index (ECI)156.8 (best)148.8
ECI rank#18 of 148 (best)#56 of 148
GPQA DiamondGraduate-level science questions—86.9%
FrontierMath Tiers 1–3Research-level mathematics—51.2%
OTIS Mock AIME 2024–2025Competition mathematics—88.9%
SWE-bench VerifiedFixing real GitHub issues74.8%—
SimpleQA VerifiedShort factual questions—29.4%
Price per million tokens
Input$1.75$0.75 (best)
Output$14.00$4.50 (best)
Cached input$0.175$0.075 (best)
Blended (3:1)$4.81$1.69 (best)
Long-context rateSame rateSame rate
Price sourceOfficial OpenAI APIOfficial OpenAI API
Limits
Context window400,000 tokens400,000 tokens
Max output128,000 tokens128,000 tokens
Inputs and features
TextYesYes
ImagesYesYes
PDFsYesNo
AudioNoNo
VideoNoNo
ReasoningYeslow · medium · high · xhighYeslow · medium · high · xhigh
Tool callingYesYes
Structured outputYesYes
Availability
WeightsProprietaryProprietary
API model IDgpt-5.3-codexgpt-5.4-mini
API providers1929 (best)
ReleasedFeb 5, 2026Mar 17, 2026
Knowledge cutoffAug 31, 2025Aug 31, 2025
03 — Cost

What would a month cost?

Enter your expected volume in millions of tokens. List prices only; caching and batch discounts would lower these.

  • GPT-5.3 Codex$45.50
  • GPT-5.4 mini$16.50
04 — Questions

Which should you choose?

Which is better: GPT-5.3 Codex or GPT-5.4 mini?

It is close. Our weighted score puts them within 1 points (GPT-5.3 Codex 64/100, GPT-5.4 mini 63/100), so choose by what matters most for your work: GPT-5.3 Codex for raw capability and GPT-5.4 mini on price. The score weighs capability 50%, price 25%, inputs & features 15%, context window 10%.

Which is cheaper, GPT-5.3 Codex or GPT-5.4 mini?

GPT-5.4 mini is cheaper at $0.75 input / $4.50 output per million tokens (official OpenAI API price). GPT-5.3 Codex costs $1.75 input / $14.00 output per million tokens (official OpenAI API price). At a typical mix of three input tokens to one output token, that is $1.69 per million tokens for GPT-5.4 mini versus $4.81 for GPT-5.3 Codex (2.9× as much).

Which scores higher on benchmarks?

GPT-5.3 Codex scores higher on the Capabilities Index (ECI): GPT-5.3 Codex 156.8 (#18 of 148) and GPT-5.4 mini 148.8 (#56 of 148). Their confidence ranges do not overlap (153.5–160.8 vs 147.1–150.5), so the gap is a real one.

Which is better for coding?

There are no published SWE-bench Verified results for GPT-5.4 mini yet, so there is no like-for-like coding score. On overall capability, GPT-5.3 Codex leads, which tends to carry over to coding, but test on your own codebase. Both support tool calling for agent workflows.

Which has the bigger context window?

GPT-5.3 Codex and GPT-5.4 mini share the same 400,000-token context window. Maximum output per response: GPT-5.3 Codex up to 128,000, GPT-5.4 mini up to 128,000 tokens.

Which can read images, PDFs, audio or video?

GPT-5.3 Codex accepts text, images and PDFs; GPT-5.4 mini accepts text and images. GPT-5.3 Codex handles the widest range of inputs.

Are any of these open source?

No. GPT-5.3 Codex and GPT-5.4 mini are proprietary and only available through APIs and apps.

Which is newer?

GPT-5.4 mini is the newest, released Mar 17, 2026. GPT-5.3 Codex came out Feb 5, 2026. Knowledge cutoff: GPT-5.3 Codex Aug 31, 2025, GPT-5.4 mini Aug 31, 2025.

How do you decide the winner?

Each model gets a 0–100 score on capability (50%, independent benchmark results); price (25%, blended price per million tokens (3 input : 1 output), log scale); inputs & features (15%, image, PDF, audio and video input, tool calling, structured output and reasoning); context window (10%, maximum tokens per request, log scale). Dimensions missing for any model are dropped and the remaining weights rescaled, so every model is judged on the same evidence. Specs and prices come from public model listings and the labs’ own API pages; capability scores come from independent benchmark runs. Data updated Oct 4, 2026.

05 — Keep comparing

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