AI Rankings
GPT-5.3 Codex vs Kimi K3: Scores, Price and Which to Choose
Side by side on every measure both models share: overall score, human votes, tests, price and context window. Close results are called too close to call.
Data updated
Read the model pages for the full picture: GPT-5.3 Codex and Kimi K3.
Side by side
A check mark shows the better side on each measure. Scores that are too close to call have no winner.
- GPT-5.3 Codex
- Kimi K3
- Epoch Capabilities IndexToo close to call
Combined score over many tests. Bar shows where it sits between the lowest and highest score we track.
GPT-5.3 Codex:157.1Kimi K3:157.9 - Arena web development ratingKimi K3 leads
Rating from head-to-head votes by people. Bar shows where it sits between the lowest and highest score we track.
GPT-5.3 Codex:1407Kimi K3:Better: 1655 - Blended price per million tokensGPT-5.3 Codex costs less
Blended price: lower is better.
GPT-5.3 Codex:Better: $4.81Kimi K3:$6.00 - Context windowKimi K3 leads
How much text it can read at once.
GPT-5.3 Codex:272K tokensKimi K3:Better: 1M tokens
The numbers
| Measure | GPT-5.3 Codex | Kimi K3 |
|---|---|---|
| Epoch Capabilities IndexToo close to call | 157.1 | 157.9 |
| Arena web development rating | 1407 | 1655 |
| Blended price per million tokens | $4.81 | $6.00 |
| Context window | 272K tokens | 1M tokens |
What it costs in everyday terms
Estimate for 100 chats of about 1,000 tokens in and 500 tokens back, from list prices. Your bill depends on how you use it.
- 100 chats with GPT-5.3 Codex
- $0.88
- Blended price $4.81 per million tokens.
- 100 chats with Kimi K3
- $1.05
- Blended price $6.00 per million tokens.
Who should pick which
Pick GPT-5.3 Codex if these matter most
- Blended price per million tokens: $4.81 against $6.00
Pick Kimi K3 if these matter most
- Arena web development rating: 1655 against 1407
- Context window: 1M tokens against 272K tokens
Too close to call: Epoch Capabilities Index.
Scores come from tests and votes, not from your own work. Try both on a task you care about before you commit.
Questions about this comparison
- Which is better, GPT-5.3 Codex or Kimi K3?
- Kimi K3 scores higher on 1 of 2 shared quality measures, GPT-5.3 Codex on 0. 1 measure is too close to call. GPT-5.3 Codex costs about 20% less than Kimi K3 on a blended price of $4.81 against $6.00 per million tokens. Which one is better for you depends on your task and budget, so test both on your own work.
- Which is cheaper, GPT-5.3 Codex or Kimi K3?
- GPT-5.3 Codex is cheaper on blended price: $4.81 per million tokens for GPT-5.3 Codex against $6.00 for Kimi K3. For 100 chats of about 1,000 tokens in and 500 tokens back, that is about $0.88 for GPT-5.3 Codex and $1.05 for Kimi K3.
- Which can read longer documents, GPT-5.3 Codex or Kimi K3?
- GPT-5.3 Codex has a context window of 272K tokens and Kimi K3 has 1M tokens.
Where this data comes from
- Epoch AI: Benchmark data: Epoch AI, 'Capabilities & benchmarking', epoch.ai/benchmarks (CC BY 4.0). We match models across sources, rank them and show them in charts. Scores are not changed. Epoch AI does not endorse this site.
- Arena (formerly LMArena): Human-preference ratings: Arena (arena.ai) leaderboard dataset, CC BY 4.0. We keep the latest published ratings, match them to models from other sources and rank them. Ratings are not changed. Arena does not endorse this site.
- LiteLLM model price list: Prices and context windows: LiteLLM model price list (github.com/BerriAI/litellm, MIT licence). We use the model maker's own price entry when there is one. Prices change often, so always confirm on the maker's site before you buy.
Newest data on this page: 26 Oct 2026. Prices are list prices and change often, so confirm on the maker's site before you buy. Sponsors never change a score or an order. How we calculate this · Report a mistake