ZMIME
Comparison · 2 models · Updated Oct 4, 2026

GPT-5.1 Chat vs Qwen3.5 Plus

Qwen3.5 Plus comes out ahead, 59 to 38 on our weighted score, and it is the cheaper option too.

  1. OpenAI

    GPT-5.1 Chat

    Released Nov 13, 2025

    38/100
    • ECI—
    • Price$1.25 / $10.00
    • Context128K
  2. Our pick

    Alibaba (Qwen)

    Qwen3.5 Plus

    Released Feb 16, 2026

    59/100
    • ECI146.8
    • Price$0.40 / $2.40
    • Context1M
  3. Add a model

    Make it a three-way comparison.

01 — Verdict

Qwen3.5 Plus is our pick

Qwen3.5 Plus is the better all-round choice, scoring 59/100 against GPT-5.1 Chat (38). It leads on price and context window. 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 priceQwen3.5 PlusQwen3.5 Plus $0.90 · GPT-5.1 Chat $3.44 per 1M tokens (3:1 blend)
  • Longest contextQwen3.5 PlusQwen3.5 Plus 1,000,000 · GPT-5.1 Chat 128,000 tokens
  • Widest inputsQwen3.5 PlusGPT-5.1 Chat: Text, Images · Qwen3.5 Plus: Text, Images, Video
  • Self-hostingNo open weightsBoth are available only through APIs
How the score is built
MeasureWeightGPT-5.1 ChatQwen3.5 Plus
Price50%2452
Inputs & features30%7070
Context window20%2460
Overall100%38/10059/100

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-5.1 Chat vs Qwen3.5 Plus specifications side by side
SpecificationGPT-5.1 ChatOpenAIQwen3.5 PlusAlibaba (Qwen)
Capability
Capabilities Index (ECI)—146.8
ECI rank—#65 of 148
GPQA DiamondGraduate-level science questions—84.9%
OTIS Mock AIME 2024–2025Competition mathematics—86.7%
SimpleQA VerifiedShort factual questions—25.4%
Price per million tokens
Input$1.25$0.40 (best)
Output$10.00$2.40 (best)
Cached input——
Blended (3:1)$3.44$0.90 (best)
Long-context rateSame rateSame rate
Price sourceMedian of 2 providersOfficial Alibaba API
Limits
Context window128,000 tokens1,000,000 tokens (best)
Max output16,384 tokens65,536 tokens (best)
Inputs and features
TextYesYes
ImagesYesYes
PDFsNoNo
AudioNoNo
VideoNoYes
ReasoningYesYes
Tool callingYesYes
Structured outputYesNo
Availability
WeightsProprietaryProprietary
API model ID—qwen3.5-plus
API providers210 (best)
ReleasedNov 13, 2025Feb 16, 2026
Knowledge cutoffSep 30, 2024Apr 2025
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-5.1 Chat$32.50
  • Qwen3.5 Plus$8.80
04 — Questions

Which should you choose?

Which is better: GPT-5.1 Chat or Qwen3.5 Plus?

Qwen3.5 Plus is the better all-round choice, scoring 59/100 against GPT-5.1 Chat (38). It leads on price and context window. 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-5.1 Chat or Qwen3.5 Plus?

Qwen3.5 Plus is cheaper at $0.40 input / $2.40 output per million tokens (official Alibaba API price). GPT-5.1 Chat costs $1.25 input / $10.00 output per million tokens (median across 2 API providers). At a typical mix of three input tokens to one output token, that is $0.90 per million tokens for Qwen3.5 Plus versus $3.44 for GPT-5.1 Chat (3.8× as much).

Which scores higher on benchmarks?

There is no independent benchmark that covers both models yet. GPT-5.1 Chat has not been scored yet and Qwen3.5 Plus has an ECI of 146.8.

Which is better for coding?

There are no published SWE-bench Verified results for GPT-5.1 Chat and Qwen3.5 Plus 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?

Qwen3.5 Plus has the largest context window at 1,000,000 tokens, against 128,000 for GPT-5.1 Chat. Maximum output per response: GPT-5.1 Chat up to 16,384, Qwen3.5 Plus up to 65,536 tokens.

Which can read images, PDFs, audio or video?

GPT-5.1 Chat accepts text and images; Qwen3.5 Plus accepts text, images and video. Qwen3.5 Plus handles the widest range of inputs.

Are any of these open source?

No. GPT-5.1 Chat and Qwen3.5 Plus are proprietary and only available through APIs and apps.

Which is newer?

Qwen3.5 Plus is the newest, released Feb 16, 2026. GPT-5.1 Chat came out Nov 13, 2025. Knowledge cutoff: GPT-5.1 Chat Sep 30, 2024, Qwen3.5 Plus Apr 2025.

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.