Head-to-head comparison

Kimi K3 vs o3

Kimi K3 (Moonshot AI) and o3 (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, Kimi K3 holds the stronger ModelCap Index position (#3 vs #37); o3 is 1.9× cheaper per output token ($8.00/1M vs $15.00/1M); and Kimi K3 offers the longer context window (1M vs 200K tokens).

Which should you choose?

Choose Kimi K3 if…

you want the stronger overall ModelCap Index position — #3 against #37 (81.2 vs 55.1 points).
you need the longer context window — 1M tokens against 200K.
you want provider choice — 12 listed API providers against 1.
Arena coding is your yardstick — 1543 against 1460.
ARC-AGI-2 is your yardstick — 60.4% against 6.5%.
Artificial Analysis Intelligence Index is your yardstick — 59.7 against 31.1.
you want the more recently listed model — Kimi K3 was listed 16 July 2026, o3 16 April 2025.

Choose o3 if…

API cost matters — $8.00/1M output tokens against $15.00/1M, about 1.9× cheaper.
your workload is prompt-heavy — input tokens cost $2.00/1M against $3.00/1M.

Kimi K3 vs o3: specs, pricing and context

Specification comparison of Kimi K3 and o3
Field	Kimi K3Moonshot AI	o3OpenAI
ModelCap Index position	#3	#37
Index score	81.2	55.1
Evidence	Measured	Measured
Input price / 1M tokens	$3.00	$2.00
Output price / 1M tokens	$15.00	$8.00
Context window	1M tokens	200K tokens
Max output tokens	1M	100K
API providers listed	12	1
Weight access	Restricted license	API only
Input modalities	Text, Image, Video	Image, Text, File
First listed	16 July 2026	16 April 2025
Publisher	Moonshot AI	OpenAI

Evidence: 6 public benchmark observations across 6 boards · 4 public benchmark observations across 4 boards. Prices are the lowest listed API offer per million tokens observed on the OpenRouter catalogue.

Benchmark scores: Kimi K3 vs o3

Public benchmark boards where Kimi K3 or o3 has a published result
Board	Kimi K3	o3	Leads
Arena codingArena (LMArena)	15431532–1554Max	14601453–1466	Kimi K3
LMArena AgentLMArena	10.6%9.6%–11.6%Max	—	Only one result
ARC-AGI-2ARC Prize Foundation	60.4%Max	6.5%High	Kimi K3
SWE-benchSWE-bench (Princeton / SWE-agent team)	—	58.4%	Only one result
BFCL V4UC Berkeley (Gorilla)	—	63.1Prompt	Only one result
WildClawBench OpenClawWildClawBench	54.5	—	Only one result
Artificial Analysis Intelligence IndexArtificial Analysis	59.7intelligence-index	31.1intelligence-index	Kimi K3

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 K3 vs o3: common questions

Is Kimi K3 better than o3?

Kimi K3 ranks higher on the ModelCap Index as of 18 August 2026: #3 against #37. 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 K3 cheaper than o3?

o3 is cheaper on output tokens: $8.00/1M against $15.00/1M. Input tokens are $3.00/1M for Kimi K3 and $2.00/1M for o3. Prices are the lowest listed API offer ModelCap observed, in USD per million tokens.

Which has the bigger context window, Kimi K3 or o3?

Kimi K3 has the larger context window: 1M tokens against 200K.

Which is better for coding, Kimi K3 or o3?

Arena coding: Kimi K3 1543, o3 1460 — Kimi K3 leads.

Are Kimi K3 and o3 open-weight models?

Kimi K3: Restricted license. o3: 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 K3 and o3?

ModelCap currently lists 12 API providers for Kimi K3 and 1 for o3, from the OpenRouter catalogue snapshot the site serves; each model page lists the providers and their prices.

How current is this Kimi K3 vs o3 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.