Kimi K3 vs GPT-5.5 — LLM API Cost Comparison
Compare Kimi K3 (Kimi (Moonshot AI)) vs GPT-5.5 (OpenAI) on cost per million tokens, context window, and monthly spend.
Prices verified 2026-08-03 · Pricing may change — use the calculator for current estimates
- Input
- $3/1M tokens
- Output
- $15/1M tokens
- Context
- 1M tokens
- Released
- 2026-07
Kimi flagship; $0.30/1M cached input, 1M context, native multimodal and reasoning
- Input
- $5/1M tokens
- Output
- $30/1M tokens
- Context
- 272K tokens
- Released
- 2026-04
Latest OpenAI frontier model; 272K context standard tier
Monthly Cost by Usage Tier (70% input / 30% output ratio)
| Usage | Kimi K3 | GPT-5.5 | Cheaper by |
|---|---|---|---|
| Light (1M tokens) | $6.60 | $12.50 | Kimi K3 (47%) |
| Moderate (10M tokens) | $66.00 | $125 | Kimi K3 (47%) |
| Heavy (100M tokens) | $660 | $1,250 | Kimi K3 (47%) |
| Very Heavy (1B tokens) | $6,600 | $12,500 | Kimi K3 (47%) |
Frequently Asked Questions
Which is cheaper — Kimi K3 or GPT-5.5?
For input tokens, Kimi K3 is cheaper at $3/1M tokens — 1.7× less than $5/1M. For output tokens, Kimi K3 wins at $15/1M vs $30/1M. At heavy workloads (100M tokens/month), the cost difference can be significant.
What is the context window difference between Kimi K3 and GPT-5.5?
Kimi K3 supports 1,048,576 tokens per request; GPT-5.5 supports 272,000 tokens. Kimi K3 wins on context length, making it better for long documents, large codebases, or extended conversations without chunking.
When should I choose Kimi K3 over GPT-5.5?
Choose Kimi K3 (Kimi (Moonshot AI)) if you prefer Kimi (Moonshot AI)'s ecosystem, tooling, or reliability track record. Kimi flagship; $0.30/1M cached input, 1M context, native multimodal and reasoning. Choose GPT-5.5 (OpenAI) if Latest OpenAI frontier model; 272K context standard tier. the price/performance fits your workload better. Use this calculator to find the break-even point for your exact token volume.
How much does 1 billion tokens cost on Kimi K3 vs GPT-5.5?
At 700M input + 300M output tokens (1B total): Kimi K3 costs $6600; GPT-5.5 costs $12500. The difference is $5900/billion tokens at this 70/30 input/output ratio.