Claude Opus 4.6 vs MiniMax M3

Pricing math

Provider list price: Opus 4.6 runs $5.00/M input and $25.00/M output. M3 runs $0.30/M input and $1.20/M output. On OpenKey, add the flat 3% fee: Opus 4.6 becomes $5.15/M input and $25.75/M output; M3 becomes $0.309/M input and $1.236/M output.

For a realistic workload — 10M input tokens, 2M output tokens — Opus 4.6 costs $100.00 and M3 costs $5.40. That's an 18.5x cost gap for the same job. The input price ratio alone is 16.67x. If you're running batch jobs, evaluation pipelines, or anything at scale, that difference compounds fast. Opus 4.6 also charges for cache writes ($6.25/M) where M3 doesn't list a cache-write price at all, and M3's cache-read price ($0.06/M) is a fraction of Opus 4.6's ($0.50/M).

Coding and agent performance

On Design Arena's fullstack agent category, Opus 4.6 scores 1288 elo (rank 4, 68.6% win rate) versus... M3 doesn't have a fullstack score at all — its only agent-category result is androidnative, where it scores 990 elo (rank 27, 20.6% win rate) against Opus 4.6's 1216 elo (rank 11, 68.8% win rate). That's a 226-point elo gap and a 48-point win-rate gap on the same task.

Across model-quality categories (codecategories, uicomponent, website, gamedev), Opus 4.6 consistently lands rank 3-6 with win rates in the low-to-mid 60s. M3 lands rank 11-20 with win rates in the 50s. Artificial Analysis independently scores M3 at 58.6 on coding, 44.4 overall intelligence, and 35.4 agentic — no equivalent AA numbers exist for Opus 4.6 in this data, so the Design Arena gap is the fairer side-by-side.

Context and long-document work

Functionally tied. Opus 4.6 offers 1,000,000 tokens of context; M3 offers 1,048,576 — a context ratio of 0.95, meaning M3 has a very slight edge in raw window size. The bigger difference is max output: Opus 4.6 caps completions at 128,000 tokens, while M3 allows up to 512,000 tokens of output. If your task needs to generate very long single responses (full codebases, long reports), M3's output ceiling is 4x higher.

Modality differences

Opus 4.6 accepts text, image, and file input, outputting text. M3 accepts text, image, and video input, also outputting text only. If your pipeline needs to reason over video (frame analysis, video QA, video-grounded agents), M3 is the only one of the two that supports it natively — Opus 4.6 has no video input modality listed.

When to pick each

Pick Opus 4.6 when the task is coding-heavy, agentic, and correctness-sensitive — fullstack app generation, multi-step tool use, production agent loops — where its Design Arena wins (rank 3-4 in most categories) justify the 18.5x cost premium on a mixed workload. Pick M3 when you're running high-volume or exploratory work: batch generation, first-pass drafts, video-input tasks, or anything where a $5.40 job cost versus $100.00 changes what's economically feasible to run at scale. Both models are available on OpenKey with one API key, billed at provider list price plus a flat 3% fee — no separate contracts needed to switch between them.

Questions

Is MiniMax M3 really 18x cheaper than Claude Opus 4.6?

For a 10M input / 2M output token workload, yes: M3 costs $5.40 versus Opus 4.6's $100.00 on OpenKey pricing (provider price plus 3% fee). The input price ratio alone is 16.67x ($0.309/M vs $5.15/M).

Which model has a bigger context window?

M3 edges it slightly: 1,048,576 tokens versus Opus 4.6's 1,000,000, a context ratio of 0.95. In practice they're both roughly 1M-token models, so this isn't the deciding factor.

Which model is better for coding?

Opus 4.6 wins on Design Arena's coding-related categories, ranking 3-6 across codecategories, uicomponent, and website with win rates in the low-to-mid 60s, versus M3's rank 11-18 in the same categories. Artificial Analysis independently puts M3's coding index at 58.6.

Can I use both models with one API setup?

Yes. Both Claude Opus 4.6 and MiniMax M3 are available on OpenKey with a single API key, billed at provider list price plus a flat 3% fee — no need to manage separate accounts or contracts for each lab.