ZMIME
Comparison · 2 models · Updated Oct 4, 2026

GPT-5.3 Codex Spark vs GPT-5-Codex

GPT-5-Codex comes out ahead, 42 to 38 on our weighted score, and it is the cheaper option too.

  1. OpenAI

    GPT-5.3 Codex Spark

    Released Feb 5, 2026

    38/100
    • ECI—
    • Price$1.75 / $14.00
    • Context128K
    Full specs Remove GPT-5.3 Codex Spark
  2. Our pick

    OpenAI

    GPT-5-Codex

    Released Sep 15, 2025

    42/100
    • ECI—
    • Price$1.25 / $10.00
    • Context400K
    Full specs Remove GPT-5-Codex

  3. Add a model

    Make it a three-way comparison.

01 — Verdict

GPT-5-Codex is our pick

GPT-5-Codex is the better all-round choice, scoring 42/100 against GPT-5.3 Codex Spark (38). It leads on price and context window. GPT-5.3 Codex Spark wins on inputs & features. The score weighs price 50%, inputs & features 30%, context window 20%. None of the shared benchmarks cover every model here yet, so capability is left out of this verdict.

  • CapabilityNot enough dataNo independent benchmark covers every model here yet
  • Lowest priceGPT-5-CodexGPT-5-Codex $3.44 · GPT-5.3 Codex Spark $4.81 per 1M tokens (3:1 blend)
  • Longest contextGPT-5-CodexGPT-5-Codex 400,000 · GPT-5.3 Codex Spark 128,000 tokens
  • Widest inputsGPT-5.3 Codex SparkGPT-5.3 Codex Spark: Text, Images, PDFs · GPT-5-Codex: Text, Images
  • Self-hostingNo open weightsBoth are available only through APIs
How the score is built
MeasureWeightGPT-5.3 Codex SparkGPT-5-Codex
Price50%1824
Inputs & features30%8070
Context window20%2444
Overall100%38/10042/100

Left out because at least one model lacks the data: capability. The remaining weights were rescaled.

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 Spark vs GPT-5-Codex specifications side by side
SpecificationGPT-5.3 Codex SparkOpenAIGPT-5-CodexOpenAI
Capability
Capabilities Index (ECI)——
ECI rank——
Price per million tokens
Input$1.75$1.25 (best)
Output$14.00$10.00 (best)
Cached input$0.175—
Blended (3:1)$4.81$3.44 (best)
Long-context rateSame rateSame rate
Price sourceOfficial OpenAI APIMedian of 3 providers
Limits
Context window128,000 tokens400,000 tokens (best)
Max output32,000 tokens128,000 tokens (best)
Inputs and features
TextYesYes
ImagesYesYes
PDFsYesNo
AudioNoNo
VideoNoNo
ReasoningYeslow · medium · high · xhighYes
Tool callingYesYes
Structured outputYesYes
Availability
WeightsProprietaryProprietary
API model IDgpt-5.3-codex-spark—
API providers13 (best)
ReleasedFeb 5, 2026Sep 15, 2025
Knowledge cutoffAug 31, 2025Sep 30, 2024
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 Spark$45.50
  • GPT-5-Codex$32.50
04 — Questions

Which should you choose?

Which is better: GPT-5.3 Codex Spark or GPT-5-Codex?

GPT-5-Codex is the better all-round choice, scoring 42/100 against GPT-5.3 Codex Spark (38). It leads on price and context window. GPT-5.3 Codex Spark wins on inputs & features. The score weighs price 50%, inputs & features 30%, context window 20%. None of the shared benchmarks cover every model here yet, so capability is left out of this verdict.

Which is cheaper, GPT-5.3 Codex Spark or GPT-5-Codex?

GPT-5-Codex is cheaper at $1.25 input / $10.00 output per million tokens (median across 3 API providers). GPT-5.3 Codex Spark 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 $3.44 per million tokens for GPT-5-Codex versus $4.81 for GPT-5.3 Codex Spark (1.4× as much).

Which scores higher on benchmarks?

There is no independent benchmark that covers both models yet. GPT-5.3 Codex Spark has not been scored yet and GPT-5-Codex has not been scored yet.

Which is better for coding?

There are no published SWE-bench Verified results for GPT-5.3 Codex Spark and GPT-5-Codex yet, so there is no like-for-like coding score. Test both on a sample of your own tasks. Both support tool calling for agent workflows.

Which has the bigger context window?

GPT-5-Codex has the largest context window at 400,000 tokens, against 128,000 for GPT-5.3 Codex Spark. Maximum output per response: GPT-5.3 Codex Spark up to 32,000, GPT-5-Codex up to 128,000 tokens.

Which can read images, PDFs, audio or video?

GPT-5.3 Codex Spark accepts text, images and PDFs; GPT-5-Codex accepts text and images. GPT-5.3 Codex Spark handles the widest range of inputs.

Are any of these open source?

No. GPT-5.3 Codex Spark and GPT-5-Codex are proprietary and only available through APIs and apps.

Which is newer?

GPT-5.3 Codex Spark is the newest, released Feb 5, 2026. GPT-5-Codex came out Sep 15, 2025. Knowledge cutoff: GPT-5.3 Codex Spark Aug 31, 2025, GPT-5-Codex Sep 30, 2024.

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

Related comparisons