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Model comparison · Updated 1 Sep 2026

Mistral Medium 3.5 vs GPT-5.1

GPT-5.1 is about 1.2× cheaper on input ($1.25 against $1.50 per 1M tokens), though Mistral Medium 3.5 is cheaper on output. GPT-5.1 has the larger context window (400K against 262K tokens). For a support chatbot at 10,000 chats a day, the standard-tier bill is about $1,350 a month for Mistral Medium 3.5 and $1,463 for GPT-5.1.

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ModelsAtlas. “Mistral Medium 3.5 vs GPT-5.1”. Retrieved 1 Sep 2026. https://modelsatlas.com/compare/mistralai/mistral-medium-3-5/vs/openai/gpt-5-1

Model A

Mistral Medium 3.5

by Mistral AI · weights not marked open · GRIDE4

Input / 1M
$1.50
observed We measured
Source
Our catalogue
Retrieved
17 Aug 2026
Output / 1M$7.50
Context262K
vs

Model B

GPT-5.1

by OpenAI · weights not marked open · GRIDE4

Input / 1M
$1.25
observed We measured
Source
Our catalogue
Retrieved
17 Aug 2026
Output / 1M$10.00
Context400K

Key numbers

Standard tier · highlighted = better

Mistral Medium 3.5
GPT-5.1
Input / 1M tokens
$1.50
$1.25
Output / 1M tokens
$7.50
$10.00
Batch input / output
$0.75 / $3.75
$0.63 / $5.00
Context window
262,144
400,000
Input types
Not disclosed
Not disclosed
Weights
Not marked open
Not marked open
Tiers listed
batch, standard
batch, standard
Prices checked
2026-09-01
2026-08-17

What it costs for real workloads

Monthly, standard tier, 30 days

Support chatbot10k chats/day · 1.5k in, 300 out
$1,350/mo
$1,463/mo
RAG over documents2k queries/day · 12k in, 500 out
$1,305/mo
$1,200/mo
Coding agent300 tasks/day · 60k in, 8k out
$1,350/mo
$1,395/mo

Mistral Medium 3.5   GPT-5.1 · Derived from the standard-tier prices above, input and output tokens per request as stated, 30 days. Excludes caching discounts and batch. Try your own numbers.

On the atlas

Price band (A–H) × context band (1–6)

Same square. Mistral Medium 3.5 and GPT-5.1 share E4.

Same square as Mistral Medium 3.5: GPT-5 ($1.25), GPT-5.1-Codex ($1.25), GPT-5.2 ($1.75). Open E4

AFreeB<$0.10C$0.10–0.30D$0.30–1E$1–3F$3–10G$10–30H$30+1<32K232–128K3128–256K4256K–1M51M6>1MINPUT PRICE PER 1M TOKENS →CONTEXT WINDOW ↑ · position within a square follows the real valueGPT-5.2 · E4GPT-5.2-Codex · E4GPT-5.3-Codex · E4GPT-5 · E4GPT-5.1-Codex · E4Mistral Medium 3.5Mistral Medium 3.5GPT-5.1GPT-5.1
Mistral Medium 3.5GPT-5.1Nearest neighboursOpen weights
View the map as a table (1 squares)
SquarePrice bandContext bandModels
GRIDE4$1–3256K–1MMistral Medium 3.5, GPT-5.1, GPT-5.2, GPT-5.2-Codex, GPT-5.3-Codex, GPT-5, GPT-5.1-Codex

Capabilities side by side

Only what our records list

Mistral Medium 3.5
GPT-5.1
Vision input
Not disclosed
Not disclosed
Audio input
Not disclosed
Not disclosed
Open weights
Not marked open
Not marked open
Batch tier
Supported
Supported
Free tier
Not listed
Not listed
Thinking tier
Not listed
Not listed

Neither record lists input types, so we do not claim any.

Which should you choose?

Editorial

Choose Mistral Medium 3.5 if…

  • output dominates your bill: $7.50 per 1M output against $10.00

Choose GPT-5.1 if…

  • you pay by the token: it costs $1.25 per 1M input against $1.50
  • your prompts are long: it takes 400,000 tokens against 262,144

Each reason is a fact from the tables above. Picking between them is our judgement, and we do not benchmark quality: price and context are what we can measure, so test both on your own prompts before you commit.

Questions

Is Mistral Medium 3.5 better than GPT-5.1?
We do not benchmark quality, so we cannot say. On the recorded numbers: GPT-5.1 is about 1.2× cheaper on input ($1.25 against $1.50 per 1M tokens), though Mistral Medium 3.5 is cheaper on output. GPT-5.1 has the larger context window (400K against 262K tokens). For a support chatbot at 10,000 chats a day, the standard-tier bill is about $1,350 a month for Mistral Medium 3.5 and $1,463 for GPT-5.1. Which is better for you depends on your task; test both on your own prompts.
Which is cheaper, Mistral Medium 3.5 or GPT-5.1?
GPT-5.1: $1.25 against $1.50 per 1M input tokens, and $10.00 against $7.50 per 1M output, on standard pricing.
How much does each cost per 1M tokens?
Mistral Medium 3.5: $1.50 input and $7.50 output. GPT-5.1: $1.25 input and $10.00 output. Standard tier, USD.
Which has the larger context window?
GPT-5.1, with 400,000 tokens. Mistral Medium 3.5 has 262,144 tokens.
Do both offer batch pricing?
Mistral Medium 3.5 lists a batch tier, at 50% of its standard price. GPT-5.1 lists a batch tier, at 50% of its standard price.
Can both read images or audio?
Input types recorded for Mistral Medium 3.5: none recorded. For GPT-5.1: none recorded. Where a record lists none we say so rather than guess; check each vendor's documentation before relying on a capability.
Is either model open-weight?
Mistral Medium 3.5: not marked open-weight in our records. GPT-5.1: not marked open-weight in our records.
What would each cost for a support chatbot?
At 10,000 chats a day, 1,500 input and 300 output tokens each, 30 days, standard tier: about $1,350 a month for Mistral Medium 3.5 and $1,463 for GPT-5.1. This is our calculation from the listed prices, not a quote.

About the two models

Mistral Medium 3.5

By Mistral AI. $1.50 input and $7.50 output per 1M tokens, 262K context, atlas square E4. Tiers listed: batch, standard.

Full specs & pricing →

GPT-5.1

By OpenAI. $1.25 input and $10.00 output per 1M tokens, 400K context, atlas square E4. Tiers listed: batch, standard.

Full specs & pricing →

Compare Mistral Medium 3.5 with…

Compare GPT-5.1 with…

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