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gpt-oss-120b vs Kimi K3

Compare gpt-oss-120b from OpenAI and Kimi K3 from Moonshot AI on key metrics including benchmarks, price, context length, and other model features. Access both models and hundreds of others through the AIHubMix API.

OpenAIgpt-oss-120bMoonshot AIKimi K3
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OpenAI logo
gpt-oss-120b
OpenAI · text → text

gpt-oss-120b is a 117B-parameter open-weight Mixture-of-Experts (MoE) language model from OpenAI, designed for high-reasoning, agentic, and general-purpose production use cases. Activating just 5.1B parameters per pass, it is optimized to run on a single H100 GPU with native MXFP4 quantization. The model features configurable reasoning depth, full chain-of-thought access, and native tool use, including function calling, browsing, and structured output generation.

Input$0.18 /M
Output$0.90 /M
Details
Moonshot AI logo
Kimi K3
Moonshot AI · text, image, video → text

Kimi K3 is Kimi’s flagship model for long-horizon coding and end-to-end knowledge work, with a 1M-token context window and industry-leading intelligence.

Input$3.00 /M
Output$15.00 /M
Details

Pricing & Specifications

Prices are per million tokens. Time to First Token and throughput are rolling averages measured on AIHubMix.

gpt-oss-120b
Kimi K3
Input /M
$0.18
$3.00
Output /M
$0.90
$15.00
Cache read /M
$0.18
$0.30
Context length
131,072
1,048,576
Max output
32,768
1,048,576
Time to First Token
0.2 s
0.9 s
Throughput
1101.0 tok/s
73.1 tok/s
Modalities
text
textimagevideo
Supported Parameters
thinkingfunction callingstructured outputs
thinkingfunction callingstructured outputs
API Formats
Released
-
-

Promotional prices show the discounted rate; see each model page for promotion windows.

Activity Past 30 Days

Daily traffic served through AIHubMix — how demand for each model is trending.

gpt-oss-120bkimi-k3

Tokens / day

-

Requests / day

-

Performance Past 3 Days

Measured on real AIHubMix traffic, hourly buckets. Gaps mean no traffic in that hour.

gpt-oss-120bkimi-k3

Throughput (tok/s)

-

TTFT (s)

-

Uptime (%)

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LMArena Benchmarks

LMArena ratings by capability (Bradley-Terry, commonly called Elo). Higher is better.

Text
gpt-oss-120bkimi-k3
1260134014201500
Overall
13521486
Coding
13901531
Math
13811381
Hard prompts
13621505
Instruction following
13251479
Multi-turn
13271499
Creative writing
12771470
Longer query
13251502
Chinese
13721527
English
13601491

Source: LMArena (arena.ai) leaderboard, imported by AIHubMix. Models without published ratings are omitted per chart.

Cost calculator

Estimate your monthly bill for the same workload on each model.

gpt-oss-120b
$24.30 /mo
Kimi K3
$405 /mo

Monthly = daily × 30. Discounted rates applied where a promotion is active.

FAQ

Which is cheaper: gpt-oss-120b, Kimi K3?

gpt-oss-120b: $0.90/M output tokens; Kimi K3: $15.00/M. Use the cost calculator above to estimate your own workload.

How do their coding arena scores compare?

Kimi K3: 1531; gpt-oss-120b: 1390 (LMArena coding leaderboard).

Which responds faster?

gpt-oss-120b: 0.2s time to first token measured on AIHubMix; see the live performance charts above for how each model behaves across the day.

How large is each context window?

gpt-oss-120b accepts 131,072 and Kimi K3 accepts 1,048,576 input tokens. Maximum output per request is 32,768 tokens on gpt-oss-120b and 1,048,576 tokens on Kimi K3.

Which one generates tokens faster?

gpt-oss-120b at 1101.0 tok/s and Kimi K3 at 73.1 tok/s, measured as output throughput on AIHubMix — a separate metric from time to first token.

What inputs and capabilities does each model support?

gpt-oss-120b accepts text input and supports thinking, function calling and structured outputs; Kimi K3 accepts text, image and video input and supports thinking, function calling and structured outputs.

Can I call gpt-oss-120b and Kimi K3 with the same API key?

Yes. AIHubMix serves every model on this page behind one OpenAI-compatible endpoint, so switching between them is a one-line change to the model field — no second account, key or SDK.

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