The Known Good Updated 29 Jul 2026
OpenAI: GPT-5 vs OpenAI: GPT-5 Nano ·OpenAI vs OpenAI

OpenAI: GPT-5 vs OpenAI: GPT-5 Nano — head-to-head comparison

OpenAI: GPT-5 profile OpenAI: GPT-5 Nano profile All comparisons
OpenAI: GPT-5 — OpenAI
Quality
#18 of 62
78based on 6 of 7 evaluations
Known Good Index
Speed
#159 of 317
48.3
Output tokens per second
Price
#289 of 370
$3.44
Blended per 1M tokens
In $1.25 · Out $10.00
Cache hit price
#130 of 238
$0.12
per 1M tokens (−90%)
Context
#136 of 375
400k
tokens (~600 pages)
OpenAI: GPT-5 Nano — OpenAI
Quality
#32 of 62
67based on 4 of 7 evaluations
Known Good Index
Speed
#47 of 317
97.5
Output tokens per second
Price
#58 of 370
$0.14
Blended per 1M tokens
In $0.05 · Out $0.40
Cache hit price
#14 of 238
$0.005
per 1M tokens (−90%)
Context
#120 of 375
400k
tokens (~600 pages)
Summary

On the Known Good Index, OpenAI: GPT-5 scores 78 and OpenAI: GPT-5 Nano scores 67 — a 11-point lead for OpenAI: GPT-5. They share 4 published evaluations, with OpenAI: GPT-5 ahead on 4 and OpenAI: GPT-5 Nano ahead on 0.

Blended pricing is $3.44 per 1M tokens for OpenAI: GPT-5 and $0.14 for OpenAI: GPT-5 Nano — OpenAI: GPT-5 Nano is about 25.0× cheaper.

Throughput is 48 tokens per second for OpenAI: GPT-5 and 98 for OpenAI: GPT-5 Nano, with time to first token at 2.1s and 2.3s. OpenAI: GPT-5 accepts 400k tokens of context against 400k.

OpenAI: GPT-5 is proprietary; OpenAI: GPT-5 Nano is proprietary. 2 tracked hosts serve one or both, and 2 serve both.

Generated from tracked data on 29 Jul 2026 · how these comparisons are computed →

At a glance
MetricOpenAI: GPT-5OpenAI: GPT-5 Nano
Known Good Index 78 based on 6 of 7 evaluations 67 based on 4 of 7 evaluations
Blended $/1M $3.44 $0.14
Output tok/s 48 98
Context window 400k 400k
Providers 2 2
Jump to section

Quality

Known Good Index and the capability indices, side by side

Index scores

Each index is min-max normalised across tracked models and scaled 0–100 from published evaluations. We do not run these evaluations.

MetricOpenAI: GPT-5OpenAI: GPT-5 Nano
Known Good Index 78 67
Coding Index 67 —
Mathematics Index 96 89
Reasoning Index 71 —
Agentic Index 67 21
Openness Index 5 5
The Known Good

Quality Breakdown

Every evaluation both models report a published score for

Evaluations both models report

Bar = OpenAI: GPT-5 · marker = OpenAI: GPT-5 Nano · scores ingested from Epoch AI (CC-BY 4.0)

GPQA Diamond86 / 69
Mock AIME 2024–2591 / 81
MATH Level 598 / 95
Terminal-Bench50 / 22

Right-hand figures read OpenAI: GPT-5 / OpenAI: GPT-5 Nano. OpenAI: GPT-5 leads on 4 of 4, OpenAI: GPT-5 Nano on 0.

The Known Good

Arena Elo

Human preference rating from blind pairwise votes

Arena ratings

Elo from blind pairwise votes, ingested from Arena. Higher is better.

Neither model currently appears in an arena we ingest.

The Known Good

Price & Cost

Published API pricing by token type

Published pricing

USD per 1M tokens. Blended is a 3:1 input:output mix. Live from OpenRouter, cross-checked against models.dev. Lower is better.

MetricOpenAI: GPT-5OpenAI: GPT-5 Nano
Input $/1M $1.25 $0.05
Output $/1M $10.00 $0.40
Blended $/1M $3.44 $0.14
Cache read $/1M $0.125 $0.005
The Known Good
We publish blended price rather than cost-per-task. Cost-per-task requires token counts from an evaluation suite we do not run. Blended price is computed from published rates and is fully reproducible — see the pricing methodology.

Context Window

Maximum input accepted and maximum output emitted

Context and output limits

Provider-declared limits, from metadata via models.dev and OpenRouter. Higher is better.

MetricOpenAI: GPT-5OpenAI: GPT-5 Nano
Context window 400k 400k
Max output tokens 128k 128k
The Known Good

Speed & Latency

Median throughput and time to first token across hosting providers

Output speedTime to first token
Throughput and latency

Medians across all tracked providers, derived from OpenRouter endpoint telemetry.

MetricOpenAI: GPT-5OpenAI: GPT-5 Nano
Output tokens/s 48 98
Time to first token 2.1s 2.3s
The Known Good

Providers

Which hosts serve each model, and at what price and speed

2 hosts · 2 serve both
Full provider benchmarks →
Provider OpenAI: GPT-5 blendedOpenAI: GPT-5 tok/s OpenAI: GPT-5 Nano blendedOpenAI: GPT-5 Nano tok/s
OpenAI · first party $3.44 67 $0.07 186
Azure · first party $3.44 46 $0.14 58

Per-host pricing and telemetry from OpenRouter. A dash means that host does not serve that model.

The Known Good
Sources for this page
Pricing & providers — OpenRouter Metadata — models.dev Benchmarks — Epoch AI (CC-BY 4.0) Full attribution →