Pairwise benchmark snapshot · Aug 16, 2026noindex (thin pair)

OpenAI: GPT-5.3-Codex vs OpenAI: o3 Mini benchmark

Name: OpenAI: GPT-5.3-Codex vs OpenAI: o3 Mini AI benchmark comparison
Creator: CompareLLM
License: https://creativecommons.org/licenses/by/4.0/

This page compares OpenAI: GPT-5.3-Codex (OpenAI) and OpenAI: o3 Mini (OpenAI) using the latest snapshots we have as of Aug 16, 2026. OpenAI: o3 Mini wins on output price at $4.4/1M. OpenAI: GPT-5.3-Codex has the larger context window (400k tokens). Every cell below is a dated snapshot from a named public source — we do not invent missing scores, and we do not run SWE-bench ourselves.

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OpenAI

OpenAI: GPT-5.3-Codex

Auto-discovered from OpenRouter (openai/gpt-5.3-codex). Preview until a second source matches.

$14/1M out

OpenAI

OpenAI: o3 Mini

Auto-discovered from OpenRouter (openai/o3-mini). Preview until a second source matches.

Elo 1,560$4.4/1M out

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Quick vs:vs Claude Opus 4.5 vs Claude Opus 4.6 vs Claude Sonnet 4.5 vs Claude 3.7 Sonnet

Interactive Comparison Diagram

Matchup Breakdown

Tug-of-War Matchup Matrix

Category wins across intelligence, speed, and pricing efficiency.

OpenAI: GPT-5.3-Codex (1)vsOpenAI: o3 Mini (9)

OpenAI: GPT-5.3-Codex: 1W (10%)Overall: OpenAI: o3 MiniOpenAI: o3 Mini: 9W (90%)

← OpenAI: GPT-5.3-CodexOpenAI: o3 Mini →

OpenAI: o3 Mini (5/5)

Intelligence & Reasoning

Preference Elo, Coding proficiency, SWE-bench & LiveBench accuracy

Preference Elo

—vs1,560

Coding Elo

—vs1,585

SWE-bench

—vs78.5%

LiveBench

—vs72.4%

GPQA Diamond

—vs87.2%

OpenAI: GPT-5.3-Codex: 0WOpenAI: o3 Mini: 5W

OpenAI: o3 Mini (2/2)

Speed & Latency

Generation throughput and time to first token responsiveness

Output speed

—vs92 tok/s

Time to first token

—vs290 ms

OpenAI: GPT-5.3-Codex: 0WOpenAI: o3 Mini: 2W

OpenAI: o3 Mini (2/3)

Pricing & Capacity

Cost per million tokens and max context window length

Output price

$14/1Mvs$4.4/1M

Input price

$1.75/1Mvs$1.1/1M

Context window

400kvs200k

OpenAI: GPT-5.3-Codex: 1WOpenAI: o3 Mini: 2W

Capability Matchup Radar

Multi-Dimensional Capability Radar

Each spoke is a skill. Farther from the center is better (0–100th percentile). Tap any dot to inspect details.

Tap any node to inspect

Percentile 0–100

Dimensional AdvantageOpenAI: o3 Mini 5/6

Preference Elo

No shared data

Throughput Speed

No shared data

Price Efficiency

OpenAI: o3 Mini

$9.60/1M cheaper

Full Benchmark Score Matrix

—

Elo

High is better

—

EloHigh is better

1,560

Code Elo

High is better

—

Code EloHigh is better

1,585

LiveBench

High is better

—

LiveBenchHigh is better

72.4%

SWE-bench

High is better

—

SWE-benchHigh is better

78.5%

GPQA

High is better

—

GPQAHigh is better

87.2%

TTFT

Low is better

—

TTFTLow is better

290 ms

Speed

High is better

—

SpeedHigh is better

92 tok/s

In $

Low is better

$1.75/1M

In $Low is better

$1.1/1M+59%

Out $

Low is better

$14/1M

Out $Low is better

$4.4/1M+218%

Context

High is better

+100%400k

ContextHigh is better

200k

Interactive Simulator

Workload Cost & Savings Calculator

Simulate monthly production API costs based on published $/1M tokens.

Save up to 61% with OpenAI: o3 Mini

Monthly Volume50M tokens/mo

Quick Presets:

Token Ratio (In vs Out)70% In / 30% Out

RAG / Search (10% out)Coding / Chat (50% out)

OpenAI: GPT-5.3-Codex$271.25 / mo

In: $61.25Out: $210.00

OpenAI: o3 Mini$104.50 / mo

In: $38.50Out: $66.00

Estimated Cost Delta

OpenAI: o3 Mini is estimated to save $166.75/month ($2,001/year).

Based on 50M tokens (30% gen)

Key Selection Recommendations

1
OpenAI: o3 Mini:Pick OpenAI: o3 Mini when you are optimizing output cost.

Recommended Workload Routing

Repo / coding agentsinsufficient data

Need SWE-bench on both sides.

High-volume chatOpenAI: o3 Mini

Lower output list price ($4.4/1M).

Voice / low-latency UIinsufficient data

Need TTFT on both sides.

Long-document RAGOpenAI: GPT-5.3-Codex

Larger window (400k).

Screenshots / visionOpenAI: o3 Mini

OpenAI: o3 Mini is the side marked multimodal in the catalog.

Target Workload	Recommended Pick	Evaluation Rationale
Repo / coding agents	insufficient data	Need SWE-bench on both sides.
High-volume chat	OpenAI: o3 Mini	Lower output list price ($4.4/1M).
Voice / low-latency UI	insufficient data	Need TTFT on both sides.
Long-document RAG	OpenAI: GPT-5.3-Codex	Larger window (400k).
Screenshots / vision	OpenAI: o3 Mini	OpenAI: o3 Mini is the side marked multimodal in the catalog.

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LIVE

OpenAI

OpenAI: GPT-5.3-Codex

Elo n/a

LiveBench—

SWE-bench—

Speed—

Output cost$14/1M

OpenAI

OpenAI: o3 Mini

Elo 1,560

LiveBench72.4%

SWE-bench78.5%

Speed92 tok/s

Output cost$4.4/1M

Frequently Asked Questions

Which is better overall, OpenAI: GPT-5.3-Codex or OpenAI: o3 Mini?: We do not have preference Elo for both models, so we do not declare an overall winner. Compare the metrics that exist.
Which is better at coding, OpenAI: GPT-5.3-Codex or OpenAI: o3 Mini?: SWE-bench is missing for at least one model, so we do not rank coding from a single number.
Which is cheaper to run in production?: OpenAI: o3 Mini output tokens are $4.4/1M versus $14/1M. Input prices and retry rates still move the real bill.
Which is faster, OpenAI: GPT-5.3-Codex or OpenAI: o3 Mini?: We do not have TTFT for both models.
Which has the larger context window?: OpenAI: GPT-5.3-Codex accepts 400k tokens versus 200k.
Can I self-host either model?: Neither model is marked open-weights here. You are comparing hosted APIs.
Are these scores from CompareLLM’s own evals?: No. V1 aggregates public leaderboards (and optional first-party latency pings). Each cell names its source and date. Read /methodology.
What does preference Elo mean on this page?: Preference Elo is a crowd vote from LMArena / Arena. People see two hidden answers and pick the one they like more. The model that wins more often gets a higher Elo. That means people preferred it — not that it passed a school test. It is not SWE-bench, not accuracy, and not a number we invent. OpenAI: GPT-5.3-Codex and OpenAI: o3 Mini Elo cells are dated snapshots from the named source — we do not compute Arena ourselves.

Similar Head-to-Head Comparisons

All OpenAI: GPT-5.3-Codex matchups →|All OpenAI: o3 Mini matchups →

OpenAI: o3 Mini vs OpenAI o1-mini (previous gpt-mini)OpenAI: o3 Mini vs GPT-5 mini (next gpt-mini)GPT-5 vs OpenAI: o3 Mini GPT-4.5 Orion vs OpenAI: o3 Mini GPT-5.6 Sol vs OpenAI: o3 Mini GPT-5.6 Terra vs OpenAI: o3 Mini

OpenAI: GPT-5.3-Codex vs OpenAI: o3 Mini benchmark

Interactive Comparison Diagram

Matchup Breakdown

Tug-of-War Matchup Matrix

Category wins across intelligence, speed, and pricing efficiency.

OpenAI: GPT-5.3-Codex (1)vsOpenAI: o3 Mini (9)

OpenAI: GPT-5.3-Codex: 1W (10%)Overall: OpenAI: o3 MiniOpenAI: o3 Mini: 9W (90%)

← OpenAI: GPT-5.3-CodexOpenAI: o3 Mini →

OpenAI: o3 Mini (5/5)

Intelligence & Reasoning

Preference Elo, Coding proficiency, SWE-bench & LiveBench accuracy

Preference Elo

—vs1,560

Coding Elo

—vs1,585

SWE-bench

—vs78.5%

LiveBench

—vs72.4%

GPQA Diamond

—vs87.2%

OpenAI: GPT-5.3-Codex: 0WOpenAI: o3 Mini: 5W

OpenAI: o3 Mini (2/2)

Speed & Latency

Generation throughput and time to first token responsiveness

Output speed

—vs92 tok/s

Time to first token

—vs290 ms

OpenAI: GPT-5.3-Codex: 0WOpenAI: o3 Mini: 2W

OpenAI: o3 Mini (2/3)

Pricing & Capacity

Cost per million tokens and max context window length

Output price

$14/1Mvs$4.4/1M

Input price

$1.75/1Mvs$1.1/1M

Context window

400kvs200k

OpenAI: GPT-5.3-Codex: 1WOpenAI: o3 Mini: 2W

Recommended Workload Routing

Repo / coding agentsinsufficient data

Need SWE-bench on both sides.

High-volume chatOpenAI: o3 Mini

Lower output list price ($4.4/1M).

Voice / low-latency UIinsufficient data

Need TTFT on both sides.

Long-document RAGOpenAI: GPT-5.3-Codex

Larger window (400k).

Screenshots / visionOpenAI: o3 Mini

OpenAI: o3 Mini is the side marked multimodal in the catalog.

Target Workload	Recommended Pick	Evaluation Rationale
Repo / coding agents	insufficient data	Need SWE-bench on both sides.
High-volume chat	OpenAI: o3 Mini	Lower output list price ($4.4/1M).
Voice / low-latency UI	insufficient data	Need TTFT on both sides.
Long-document RAG	OpenAI: GPT-5.3-Codex	Larger window (400k).
Screenshots / vision	OpenAI: o3 Mini	OpenAI: o3 Mini is the side marked multimodal in the catalog.

Frequently Asked Questions

Which is better overall, OpenAI: GPT-5.3-Codex or OpenAI: o3 Mini?

We do not have preference Elo for both models, so we do not declare an overall winner. Compare the metrics that exist.

Which is better at coding, OpenAI: GPT-5.3-Codex or OpenAI: o3 Mini?

SWE-bench is missing for at least one model, so we do not rank coding from a single number.

Which is cheaper to run in production?

OpenAI: o3 Mini output tokens are $4.4/1M versus $14/1M. Input prices and retry rates still move the real bill.

Which is faster, OpenAI: GPT-5.3-Codex or OpenAI: o3 Mini?

We do not have TTFT for both models.

Which has the larger context window?

OpenAI: GPT-5.3-Codex accepts 400k tokens versus 200k.

Can I self-host either model?

Neither model is marked open-weights here. You are comparing hosted APIs.

Are these scores from CompareLLM’s own evals?

No. V1 aggregates public leaderboards (and optional first-party latency pings). Each cell names its source and date. Read /methodology.

What does preference Elo mean on this page?

Preference Elo is a crowd vote from LMArena / Arena. People see two hidden answers and pick the one they like more. The model that wins more often gets a higher Elo. That means people preferred it — not that it passed a school test. It is not SWE-bench, not accuracy, and not a number we invent. OpenAI: GPT-5.3-Codex and OpenAI: o3 Mini Elo cells are dated snapshots from the named source — we do not compute Arena ourselves.