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Head-to-head comparison

Kimi K2 Thinking vs GPT-5.5

Kimi K2 Thinking (Moonshot AI) and GPT-5.5 (OpenAI) compared on the ModelCap Index, API price, context window, provider availability, weight access and every public benchmark board they share. Figures are the same ones shown on the live rankings; nothing here is a hidden score.

Snapshot as of 18 August 2026

As of 18 August 2026, GPT-5.5 holds the stronger ModelCap Index position (#8 vs #32); Kimi K2 Thinking is 12× cheaper per output token ($2.50/1M vs $30.00/1M); and GPT-5.5 offers the longer context window (1M vs 262K tokens).

Which should you choose?

Choose Kimi K2 Thinking if…

  • API cost matters — $2.50/1M output tokens against $30.00/1M, about 12× cheaper.
  • your workload is prompt-heavy — input tokens cost $0.60/1M against $5.00/1M.

Choose GPT-5.5 if…

  • you want the stronger overall ModelCap Index position — #8 against #32 (75.7 vs 58.5 points).
  • you need the longer context window — 1M tokens against 262K.
  • you want provider choice — 3 listed API providers against 2.
  • Arena coding is your yardstick — 1520 against 1486.
  • Artificial Analysis Intelligence Index is your yardstick — 56.3 against 33.5.
  • you want the more recently listed model — GPT-5.5 was listed 24 April 2026, Kimi K2 Thinking 6 November 2025.

Kimi K2 Thinking vs GPT-5.5: specs, pricing and context

Specification comparison of Kimi K2 Thinking and GPT-5.5
FieldKimi K2 ThinkingMoonshot AIGPT-5.5OpenAI
ModelCap Index position#32#8
Index score58.575.7
EvidenceMeasuredMeasured
Input price / 1M tokens$0.60$5.00
Output price / 1M tokens$2.50$30.00
Context window262K tokens1M tokens
Max output tokens100K128K
API providers listed23
Weight accessRestricted licenseAPI only
Input modalitiesTextFile, Image, Text
First listed6 November 202524 April 2026
PublisherMoonshot AIOpenAI

Evidence: 3 public benchmark observations across 3 boards · 8 public benchmark observations across 8 boards. Prices are the lowest listed API offer per million tokens observed on the OpenRouter catalogue.

Benchmark scores: Kimi K2 Thinking vs GPT-5.5

Public benchmark boards where Kimi K2 Thinking or GPT-5.5 has a published result
BoardKimi K2 ThinkingGPT-5.5Leads
Arena codingArena (LMArena)14861481–1492Turbo15201513–1526HighGPT-5.5
LMArena AgentLMArena—8.9%7.9%–9.9%X-HighOnly one result
ARC-AGI-2ARC Prize Foundation—85.0%X-HighOnly one result
ARC-AGI-3ARC Prize Foundation—0.4%HighOnly one result
SWE-benchSWE-bench (Princeton / SWE-agent team)63.4%Thinking—Only one result
Artificial Analysis Intelligence IndexArtificial Analysis33.5intelligence-index56.3intelligence-indexGPT-5.5
Terminal-Bench 2.1 Terminus 2Terminal-Bench—78.0X-HighOnly one result
WildClawBench OpenClawWildClawBench—58.2Only one result

Scores are the sources' own published figures for each model's best evaluated configuration; ModelCap never re-runs a benchmark.

Want a different pairing? Open the interactive comparison tool to swap either model for any current ranked language model.

Kimi K2 Thinking vs GPT-5.5: common questions

Is Kimi K2 Thinking better than GPT-5.5?

GPT-5.5 ranks higher on the ModelCap Index as of 18 August 2026: #8 against #32. That is a capability ranking built from public benchmark evidence with published uncertainty; whether it is "better" for you also depends on price, context and where you can run it.

Is Kimi K2 Thinking cheaper than GPT-5.5?

Kimi K2 Thinking is cheaper on output tokens: $2.50/1M against $30.00/1M. Input tokens are $0.60/1M for Kimi K2 Thinking and $5.00/1M for GPT-5.5. Prices are the lowest listed API offer ModelCap observed, in USD per million tokens.

Which has the bigger context window, Kimi K2 Thinking or GPT-5.5?

GPT-5.5 has the larger context window: 1M tokens against 262K.

Which is better for coding, Kimi K2 Thinking or GPT-5.5?

Arena coding: Kimi K2 Thinking 1486, GPT-5.5 1520 — GPT-5.5 leads.

Are Kimi K2 Thinking and GPT-5.5 open-weight models?

Kimi K2 Thinking: Restricted license. GPT-5.5: API only. Open weights mean the checkpoint can be downloaded and self-hosted under its licence; API-only models are available solely through hosted endpoints.

Where can I run Kimi K2 Thinking and GPT-5.5?

ModelCap currently lists 2 API providers for Kimi K2 Thinking and 3 for GPT-5.5, from the OpenRouter catalogue snapshot the site serves; each model page lists the providers and their prices.

How current is this Kimi K2 Thinking vs GPT-5.5 comparison?

Every figure comes from the sealed ModelCap dataset published 18 August 2026; the page re-renders within a minute of each data refresh, and the ModelCap Index positions are the same ones shown on the live rankings.

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