Model comparison · accepted catalogue facts 2026-10-21

Kimi K2.6 vs GPT-5.5

Neither model has both an equal-or-higher measured score and an equal-or-lower estimated price in this pair. Retaining your current model is a valid outcome.

Editorial comparison: Context window divergence: GPT-5.5 (OpenAI) vs Kimi K2.6 (Moonshot AI) for long-document tasks Inclusion does not recommend either model.

Kimi K2.6

LMArena general · Elo · higher is better

Scale starts at 1040 Elo

1455.4

Balanced effective USD / 1M tokens · lower is better

$0.825/M

GPT-5.5

LMArena general · Elo · higher is better

Scale starts at 1040 Elo

1466.9

Balanced effective USD / 1M tokens · lower is better

$11.25/M

In-Depth Analysis

Kimi K2.6 vs GPT-5.5: Measured Technical Breakdown

Comprehensive comparison across measured human-preference evaluation, effective production token costs, architectural limits, and migration trade-offs.

Measured Capability (LMArena)

GPT-5.5 leads by 11.5 Elo

Kimi K2.6: 1455.4 ±4.41 · GPT-5.5: 1466.9 ±3.65 Statistically significant preference separation

Cost Comparison Across Canonical Production Workloads

Rates represent effective cost per 1M tokens under standard token blends. Cached prompt reads are factored according to workload context reuse.

Workload & Ratio	Kimi K2.6	GPT-5.5	Cost Difference	Advantage
Balanced 3 tokens in per 1 out	$0.825 /1M tokens	$11.25 /1M tokens	$10.43 (93% diff)	Kimi K2.6 costs less
Summarise Huge input, tiny output	$0.410 /1M tokens	$4.97 /1M tokens	$4.56 (92% diff)	Kimi K2.6 costs less
Chat Long cached system prompt	$0.929 /1M tokens	$13.65 /1M tokens	$12.72 (93% diff)	Kimi K2.6 costs less
Code gen Output dominates	$1.32 /1M tokens	$19.64 /1M tokens	$18.32 (93% diff)	Kimi K2.6 costs less
Agentic Context replayed each turn	$0.434 /1M tokens	$6.07 /1M tokens	$5.64 (93% diff)	Kimi K2.6 costs less

Architectural & Operational Specifications

Specification	Kimi K2.6	GPT-5.5	Operational Note
Context window	262,144 tokens	1,050,000 tokens	GPT-5.5 has a 4.0× larger context window
Max output generation	235,929 tokens	128,000 tokens	Kimi K2.6 allows longer single-turn completions
Base input price	$0.450 / 1M tokens	$5.00 / 1M tokens	Kimi K2.6 input rate is cheaper
Base output price	$1.95 / 1M tokens	$30.00 / 1M tokens	Kimi K2.6 output rate is cheaper
Cached input price	$0.045 / 1M tokens	$0.500 / 1M tokens	Kimi K2.6 offers lower cached prompt cost
Reasoning & thinking tokens	Supported; standard rates	Supported; standard rates	—
Input modalities	text, image	file, image, text	—
Tool calling / function use	Supported	Supported	—
Open weights & licence	Proprietary (API-only)	Proprietary (proprietary)	GPT-5.5 allows independent hosting or local deployment
Provider & reseller market	Moonshot AI · 17 provider offers (2.43× spread)	OpenAI · 7 provider offers (2.2× spread)	—

When to Choose Kimi K2.6

Higher maximum completion limit (235,929 tokens).
Direct integration with Moonshot AI tooling and API features.

Risks when moving from GPT-5.5 → Kimi K2.6:

Context window: 1,050,000 → 262,144 tokens.
file input is not supported by the candidate.

When to Choose GPT-5.5

Higher measured general capability (1466.9 Elo on human evaluation).
Larger context window (1,050,000 tokens) for long-document or repo-level context.
Broader multimodal input support: file, image, text.
Direct integration with OpenAI tooling and API features.

Risks when moving from Kimi K2.6 → GPT-5.5:

Output limit: 235,929 → 128,000 tokens.

Detailed Evidence Passports & Independent Audits

Kimi K2.6 Full model card, pricing ladder & provider offers → GPT-5.5 Full model card, pricing ladder & provider offers → Alternatives to Kimi K2.6 Better-and-cheaper dominance audit → Alternatives to GPT-5.5 Better-and-cheaper dominance audit →

Compare · model decision

Choose two or three models

Inspect the differences, estimate your workload and keep the evidence. All standard catalogue models are available, including unrated ones.

Catalogue facts
2026-10-21

A · Current or starting modelB · Comparison modelC · Optional third model

2 / 3 selected · 0 requirements

Open public comparison link

Public workload and requirements

These settings are included in the share link. The fixed-request scenario and private evaluation data below are excluded.

Workload Public prompt length (tokens) Required context (tokens) Required output limit (tokens) Required input modality

Tool useReasoningOpen weights

A ↔ B

Neither model has both an equal-or-higher measured score and an equal-or-lower estimated price in this pair. Retaining your current model is a valid outcome.

Estimated blend: 75% input, 25% output; 0% cached input. Base context tier. Prompt length selects the billing tier. An unlisted cache-read rate uses that tier’s full input rate in this blend; missing required input or output rates prevent an estimate. The fixed-request estimate below validates actual context and output limits and requires a published cache-read rate when cache hits are assumed.

What changes between these models

Quality first, then estimated price. LMArena scores are human-preference measurements, not a benchmark of your application. A missing score is unrated.

Kimi K2.6 · Meets the stated model requirements
GPT-5.5 · Meets the stated model requirements

Material differences and unknown evidence. Deltas compare each model with model A. Unknown facts remain visible.
Measured fact	A Kimi K2.6	B GPT-5.5
LMArena general score (Elo)	1,455.4	1,466.9Δ vs A: +11.5 Elo
Score interval half-width (± Elo)	4.41	3.65Δ vs A: -0.76 Elo
LMArena document score (Elo)	1,450.7	1,485.7Δ vs A: +35 Elo
Estimated effective USD / 1M tokens	$0.825	$11.25Δ vs A: +10.425 USD/M
Base input USD / 1M tokens	$0.45	$5Δ vs A: +4.55 USD/M
Base output USD / 1M tokens	$1.95	$30Δ vs A: +28.05 USD/M
Base cached-input USD / 1M tokens	$0.045	$0.5Δ vs A: +0.455 USD/M
Context window (tokens)	262,144	1,050,000Δ vs A: +787,856 tokens
Output limit (tokens)	235,929	128,000Δ vs A: -107,929 tokens
Input modalities	text, image	file, image, text
Open weights	Unknown	Not supported
Recorded licence	Unknown	proprietary
Model provider	Moonshot AI	OpenAI
Distinct sellers in the catalogue	17	3Δ vs A: -14
Serving precision differs across offers	Supported	Not supportedΔ vs A: -1
Recorded retirement date	Unknown	Unknown

4 shared measured facts

Shared measured facts. Deltas compare each model with model A. Unknown facts remain visible.
Measured fact	A Kimi K2.6	B GPT-5.5
Benchmark reasoning effort	default	default
Tool use	Supported	SupportedΔ vs A: 0
Reasoning	Supported	SupportedΔ vs A: 0
Retirement evidence	None announced; not a guarantee	None announced; not a guarantee

Provider counts and precision flags describe catalogue offers. They do not establish the precision, availability, region, tool behaviour or limits of your chosen endpoint. Open each model’s provider table before switching.

Complete price ladders and billing conditions

Kimi K2.6

Rates below are USD per 1M tokens. A threshold selects that whole input/output rate pair.

Input-token threshold	Input	Output	Cached input
Base, up to and including first threshold	$0.45	$1.95	$0.045

GPT-5.5

Rates below are USD per 1M tokens. A threshold selects that whole input/output rate pair.

Input-token threshold	Input	Output	Cached input
Base, up to and including first threshold	$5	$30	$0.5
> 272,000	$10	$45	$1

Migration preflight · compare each candidate with model A

Keeping Kimi K2.6 is a valid decision. No pairwise comparison certifies a drop-in replacement.

Kimi K2.6 → GPT-5.5

Known loss or failed requirement

Output limit: 235,929 → 128,000 tokens.
Provider endpoint, serving precision, availability and task success need your own verification. Catalogue model capabilities do not certify an endpoint.

Check alternatives to Kimi K2.6

Estimate a fixed request shape

Private to this tab unless you save locally or explicitly export private details. These are estimates, not observed invoices. Cross-model token counts and task success are assumptions.

Requests Input tokens per request Output tokens per request Cached share of input (%) Extra attempts per request

0.1 extra attempts means 10 extra full attempts per 100 requests. Cache writes, tool charges, taxes and unlisted charges are excluded.

Kimi K2.6Estimated total: $1.875 1,000 full attempts · base rates
GPT-5.5Estimated total: $25 1,000 full attempts · base rates

Prompt and output sensitivity · sampled scenarios

Every point recalculates the entire request shape. Tier-boundary samples include one token below, at and above each threshold. Ordering between samples is not guaranteed. Lowest known cost excludes unknown estimates and is not a replacement recommendation.

Vary input; hold output, requests, cache and retries fixed.
Input tokens	Kimi K2.6	GPT-5.5	Coverage
2,000	$1.875Lowest known	$25	All computed
4,096	$2.8182Lowest known	$35.48	All computed
32,768	$15.7206Lowest known	$178.84	All computed
131,072	$59.9574Lowest known	$670.36	All computed
271,999	ineligibleInput plus output exceeds the published context window.	$1,374.995Lowest known	Incomplete
272,000	ineligibleInput plus output exceeds the published context window.	$1,375Lowest known	Incomplete
272,001	ineligibleInput plus output exceeds the published context window.	$2,742.51Lowest known	Incomplete

Vary output; hold input, requests, cache and retries fixed.
Output tokens	Kimi K2.6	GPT-5.5
128	$1.1496	$13.84
2,048	$4.8936	$71.44
8,192	$16.8744	$255.76

Bring your observed evaluation results

JSON is parsed locally. Prompts, filenames, individual responses and extra fields are not retained. Import only aggregate measurements for selected models. Task/version labels do not establish that two evaluations used the same dataset.

Import private evaluation JSON

Expected format

[{"model":"provider/exact-model-id","task":"support-answer","version":"rubric-1","attempts":100,"successes":84,"costUsd":2.4,"latencyMs":950}]

Use the exact catalogue ID. Replace the example values with observed measurements. Omit costUsd or latencyMs when they are unknown. No public score is inferred from these observations.

Keep the decision and its evidence

A portable record retains selected facts, complete tier ladders, public requirements and the publication manifest. It also embeds the full permitted public catalogue to verify the input artifact checksum. Files are larger for this reason (up to 2 MB); local storage is limited to 12 records. Team review is local to this browser; there is no hosted collaboration.

Owner (private) Review date (private) Recorded choice (private) Rationale (private)

Include private review fields, scenario and observations in downloaded files

Store private decision records on this device

Saving is opt-in and includes private review fields. Shared comparison links never include them. Version 1 Check references remain separate and are not overwritten or guessed into this format.

Import a v2 decision JSON file

Saved local decisions · 0

No version 2 decision records are stored in this browser.

Questions this page answers

Is Kimi K2.6 a better-and-cheaper replacement for GPT-5.5?

Neither model has both an equal-or-higher measured score and an equal-or-lower estimated price in this pair. Retaining your current model is a valid outcome.

Which model is higher rated: Kimi K2.6 or GPT-5.5?

GPT-5.5 scores higher on LMArena general (1466.9 ±3.7) compared to Kimi K2.6 (1455.4 ±4.4), a margin of 11.5 Elo points. The measured confidence intervals do not overlap, demonstrating a statistically significant preference lead on human evaluations.

Which model is more cost-effective: Kimi K2.6 or GPT-5.5?

On a standard balanced workload (3 prompt tokens per 1 generated token), Kimi K2.6 costs $0.825 per 1M tokens versus $11.25 for GPT-5.5. GPT-5.5 is approximately 13.6× the price of Kimi K2.6. Base input rates are $0.450 for Kimi K2.6 and $5.00 for GPT-5.5; base output rates are $1.95 for Kimi K2.6 and $30.00 for GPT-5.5.

How do their context windows and generation limits compare?

Kimi K2.6 provides a 262,144-token context window with a maximum output limit of 235,929 tokens. GPT-5.5 provides a 1,050,000-token context window with a maximum output of 128,000 tokens. GPT-5.5 offers a 4.0× larger context capacity, making it suitable for larger repositories and multi-document workflows.

What capabilities are lost when switching between Kimi K2.6 and GPT-5.5?

Switching from Kimi K2.6 to GPT-5.5 involves: Output limit: 235,929 → 128,000 tokens. Conversely, moving from GPT-5.5 to Kimi K2.6 involves: Context window: 1,050,000 → 262,144 tokens; file input is not supported by the candidate. Run test suites on your specific prompt templates and tool declarations before cutting over production traffic.

Can Kimi K2.6 or GPT-5.5 be self-hosted or deployed privately?

Both Kimi K2.6 and GPT-5.5 are proprietary cloud models offered via managed API endpoints. Kimi K2.6 is served by Moonshot AI and 17 catalogue offers, while GPT-5.5 is served by OpenAI and 7 catalogue offers.

What is included in this comparison?

Accepted model capabilities, context and output limits, complete price-tier ladders, independent LMArena measurements and missing evidence. Provider endpoint precision and application success still need verification.

Can I compare a different workload or keep a decision record?

Yes. Change the public workload, prompt length and requirements in the comparison workspace. Fixed-request scenarios, aggregate evaluations and review notes stay local unless explicitly exported.

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Kimi K2.6 vs GPT-5.5

Kimi K2.6 vs GPT-5.5: Measured Technical Breakdown

Cost Comparison Across Canonical Production Workloads

Architectural & Operational Specifications

When to Choose Kimi K2.6

When to Choose GPT-5.5

Detailed Evidence Passports & Independent Audits

Choose two or three models

What changes between these models

Kimi K2.6

GPT-5.5

Kimi K2.6 → GPT-5.5

Estimate a fixed request shape

Bring your observed evaluation results

Keep the decision and its evidence

Saved local decisions · 0

Questions this page answers