GPT-5 vs Kimi K2.5
Complete pricing and performance comparison between OpenAI's GPT-5 and Moonshot's Kimi K2.5.
Quick Verdict
Cheaper
Kimi K2.5
2.1x cheaper input, 3.3x cheaper output
Larger Context
GPT-5
400K vs 128K
Higher Quality
Kimi K2.5
Score: 47 vs 45
Faster
GPT-5
60 vs 46 tok/s
Pricing Comparison
| Spec | GPT-5 | Kimi K2.5 | Difference |
|---|---|---|---|
| Provider | OpenAI | Moonshot | |
| Input / 1M tokens | $1.25 | $0.6 | Kimi K2.5 is 52% more expensive |
| Output / 1M tokens | $10 | $3 | Kimi K2.5 is 70% more expensive |
| Context Window | 400K | 128K | 3x difference |
| Max Output | 16K | 33K | |
| Tokenizer | o200k_base | cl100k_base |
Performance Benchmarks
| Metric | GPT-5 | Kimi K2.5 | Winner |
|---|---|---|---|
| Quality Index | 45 | 47 | Kimi K2.5 |
| Output Speed | 60 tok/s | 46 tok/s | GPT-5 |
| Time to First Token | 117.69s | 1.05s | Kimi K2.5 |
| Value (Quality/$) | 35.7 | 78.0 | Higher = better value |
Benchmark data from Artificial Analysis. Quality Index is a composite score across reasoning, coding, and knowledge tasks.
Cost at Scale
Estimated cost at different usage levels (3:1 input-to-output token ratio, typical for chat).
| Usage | GPT-5 | Kimi K2.5 | Savings |
|---|---|---|---|
Single request 1K in / 300 out | $0.0042 | $0.0015 | Kimi K2.5 saves $0.0027 |
10 requests 10K in / 3K out | $0.042 | $0.015 | Kimi K2.5 saves $0.027 |
100 requests 100K in / 30K out | $0.425 | $0.150 | Kimi K2.5 saves $0.275 |
1,000 requests 1M in / 300K out | $4.25 | $1.50 | Kimi K2.5 saves $2.75 |
10,000 requests 10M in / 3M out | $42.50 | $15.00 | Kimi K2.5 saves $27.50 |
1M requests/mo 1B in / 300M out | $4250.00 | $1500.00 | Kimi K2.5 saves $2750.00 |
Pros & Cons
GPT-5 Strengths
- +Larger context window (400K vs 128K)
- +Faster output (60 vs 46 tok/s)
Kimi K2.5 Strengths
- +Cheaper input tokens
- +Cheaper output tokens
- +Higher max output tokens
- +Higher quality score (47 vs 45)
- +Lower latency (faster first token)
When to Use Each Model
Choose GPT-5 for
- →Long documents, large codebases, or multi-turn conversations
- →Real-time applications, chat, or autocomplete
Choose Kimi K2.5 for
- →Budget-conscious projects where cost is the primary factor
- →Generating long-form content or detailed code
- →Tasks requiring maximum accuracy and reasoning
Frequently Asked Questions
Which is cheaper, GPT-5 or Kimi K2.5?
For input tokens, Kimi K2.5 is 2.1x cheaper at $0.6/1M tokens. For output tokens, Kimi K2.5 is 3.3x cheaper at $3/1M tokens. At typical usage (1M input + 300K output), GPT-5 costs $4.25 vs Kimi K2.5 at $1.50.
What's the context window difference?
GPT-5 supports 400K context (400,000 tokens), while Kimi K2.5 supports 128K (128,000 tokens). GPT-5 can handle 3x more context in a single request.
Which model has better benchmarks?
Quality Index: GPT-5 scores 45 vs Kimi K2.5 at 47. Speed: GPT-5 generates 60 tok/s vs Kimi K2.5 at 46 tok/s. Time to first token: GPT-5 at 117.69s vs Kimi K2.5 at 1.05s.
When should I choose GPT-5 over Kimi K2.5?
Choose GPT-5 when you need: Larger context window (400K vs 128K), Faster output (60 vs 46 tok/s). Choose Kimi K2.5 when you need: Cheaper input tokens, Cheaper output tokens, Higher max output tokens, Higher quality score (47 vs 45), Lower latency (faster first token).
How much would 10,000 API requests cost?
At 1K input + 300 output tokens per request (typical chat): GPT-5 = $42.50, Kimi K2.5 = $15.00. At 10K input + 1K output per request (longer conversations): GPT-5 = $225.00, Kimi K2.5 = $90.00.