The Known Good Updated 25 Jul 2026
Microsoft: Phi 4 vs OpenAI: GPT-5.1 ·Microsoft vs OpenAI

Microsoft: Phi 4 vs OpenAI: GPT-5.1 — head-to-head comparison

Microsoft: Phi 4 profile OpenAI: GPT-5.1 profile All comparisons
Microsoft: Phi 4 — Microsoft
Quality
#50 of 61
33based on 3 of 6 evaluations
Known Good Index
Speed
#142 of 316
56.1
Output tokens per second
Price
#40 of 340
$0.09
Blended per 1M tokens
In $0.07 · Out $0.14
Cache hit price
unranked
—
per 1M tokens
Context
#334 of 345
16k
tokens (~25 pages)
OpenAI: GPT-5.1 — OpenAI
Quality
#20 of 61
74based on 6 of 6 evaluations
Known Good Index
Speed
#119 of 316
61.9
Output tokens per second
Price
#261 of 340
$3.44
Blended per 1M tokens
In $1.25 · Out $10.00
Cache hit price
#105 of 206
$0.12
per 1M tokens (−90%)
Context
#101 of 345
400k
tokens (~600 pages)
Summary

On the Known Good Index, Microsoft: Phi 4 scores 33 and OpenAI: GPT-5.1 scores 74 — a 41-point lead for OpenAI: GPT-5.1. They share 9 published evaluations, with Microsoft: Phi 4 ahead on 0 and OpenAI: GPT-5.1 ahead on 9.

Blended pricing is $0.09 per 1M tokens for Microsoft: Phi 4 and $3.44 for OpenAI: GPT-5.1 — Microsoft: Phi 4 is about 39.3× cheaper.

Throughput is 56 tokens per second for Microsoft: Phi 4 and 62 for OpenAI: GPT-5.1, with time to first token at 0.2s and 1.3s. Microsoft: Phi 4 accepts 16k tokens of context against 400k.

Microsoft: Phi 4 is open weights under Open weights (unrestricted); OpenAI: GPT-5.1 is proprietary. 3 tracked hosts serve one or both.

Generated from tracked data on 25 Jul 2026 · how these comparisons are computed →

At a glance
MetricMicrosoft: Phi 4OpenAI: GPT-5.1
Known Good Index 33 based on 3 of 6 evaluations 74 based on 6 of 6 evaluations
Blended $/1M $0.09 $3.44
Output tok/s 56 62
Context window 16k 400k
Providers 1 2
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Quality

Known Good Index and the capability indices, side by side

IndicesComponents
Index scores

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

MetricMicrosoft: Phi 4OpenAI: GPT-5.1
Known Good Index 33 74
Coding Index — 68
Mathematics Index 39 89
Science Index 53 91
Reasoning Index 47 80
Agentic Index — 61
Openness Index 60 5
The Known Good

Quality Breakdown

Every evaluation both models report a published score for

Evaluations both models report

Bar = Microsoft: Phi 4 · marker = OpenAI: GPT-5.1 · scores ingested from Epoch AI (CC-BY 4.0), LiveBench (Apache-2.0)

GPQA Diamond56 / 88
MATH / AIME14 / 89
LiveBench42 / 79
LiveBench Coding31 / 72
LiveBench Data Analysis45 / 72
LiveBench Instruction Following58 / 93
LiveBench Language26 / 80
LiveBench Mathematics42 / 94
LiveBench Reasoning48 / 96

Right-hand figures read Microsoft: Phi 4 / OpenAI: GPT-5.1. Microsoft: Phi 4 leads on 0 of 9, OpenAI: GPT-5.1 on 9.

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.

MetricMicrosoft: Phi 4OpenAI: GPT-5.1
Text Arena 1,217 1,422
Text Arena (style controlled) 1,256 1,439
The Known Good

Price & Cost

Published API pricing by token type

Per token typeCache discount
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.

MetricMicrosoft: Phi 4OpenAI: GPT-5.1
Input $/1M $0.07 $1.25
Output $/1M $0.14 $10.00
Blended $/1M $0.09 $3.44
Cache read $/1M — $0.125
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.

MetricMicrosoft: Phi 4OpenAI: GPT-5.1
Context window 16k 400k
Max output tokens 16k 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.

MetricMicrosoft: Phi 4OpenAI: GPT-5.1
Output tokens/s 56 62
Time to first token 0.2s 1.3s
The Known Good

Providers

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

3 hosts
Full provider benchmarks →
Provider Microsoft: Phi 4 blendedMicrosoft: Phi 4 tok/s OpenAI: GPT-5.1 blendedOpenAI: GPT-5.1 tok/s
DeepInfra $0.09 70 — —
OpenAI · first party — — $1.72 82
Azure · first party — — $3.44 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)Benchmarks — LiveBench (Apache-2.0)Elo — Arena Full attribution →