API cost decision in 10 seconds

Claude Opus 4.6 (Fast) vs Mercury 2

Pick Mercury 2 for lower cost; pick Claude Opus 4.6 (Fast) only if the larger context window matters more.

Pricing data updated: 2026-05-26T11:08:00Z Prices normalized to USD per 1M tokens Sample workload: 1M input + 500K output

Budget verdict

Pick Mercury 2 for lower cost; pick Claude Opus 4.6 (Fast) only if the larger context window matters more.

On the standard 1M input plus 500K output workload, Mercury 2 is estimated at $0.62 vs $105 for Claude Opus 4.6 (Fast), saving $104.38 (99.4% lower).

Cost-first pickMercury 2

Context-first pickClaude Opus 4.6 (Fast)

Sample savings$104.3899.4%

10x traffic gap$1043.75

Claude Opus 4.6 (Fast) has more context, but Mercury 2 saves $104.38 on the standard workload. At 10x that traffic, the same price gap is about $1043.75. Use the calculator below to replace the sample workload with your own token volume.

Cost sensitivity

Workload Sensitivity

Same prices, different token mixes.

Mercury 2 stays cheaper across input-heavy, balanced, and output-heavy sample workloads.

Workload shape	Token mix	Better pick	Claude Opus 4.6 (Fast)	Mercury 2
Input-heavy / RAG	5M input + 500K output	Mercury 2	$225	$1.62
Balanced workload	1M input + 1M output	Mercury 2	$180	$1
Output-heavy chatbot	1M input + 5M output	Mercury 2	$780	$4

Cheaper input Mercury 2 $30 vs $0.25 / 1M

Mercury 2 is $29.75 cheaper per 1M input tokens (99.2% lower; 120x difference).

Cheaper output Mercury 2 $150 vs $0.75 / 1M

Mercury 2 is $149.25 cheaper per 1M output tokens (99.5% lower; 200x difference).

Larger context Claude Opus 4.6 (Fast) 1M vs 128K

Claude Opus 4.6 (Fast) has 872K more context (7.81x larger).

Sample workload Mercury 2 $105 vs $0.62

Mercury 2 is $104.38 cheaper on the standard workload (99.4% lower).

Estimate your workload cost

Your Workload Cost

Prices are normalized to USD per 1M tokens.

Monthly input tokens Monthly output tokens

Claude Opus 4.6 (Fast) Calculating… Estimated API cost

Mercury 2 Calculating… Estimated API cost

Cheaper for this workload Calculating… Difference: calculating…

This estimate uses normalized public API pricing per 1M tokens. It is a planning aid, not a billing quote. Verify provider pricing, limits, and terms before production use.

Quick Decision

Verdict

Mercury 2 has the lower input price; Mercury 2 has the lower output price; Claude Opus 4.6 (Fast) offers the larger context window. For the 1M input plus 500K output sample, Mercury 2 is cheaper for the standard workload.

For a 1M input token plus 500K output token workload, the estimated API cost is $105 for Claude Opus 4.6 (Fast) and $0.62 for Mercury 2.

Best Fit

Choose Claude Opus 4.6 (Fast) when you care most about larger context window.

Choose Mercury 2 when you care most about lower input-token price, and lower output-token price.

Decision Notes

On the standard 1M input plus 500K output workload, Mercury 2 is estimated at $0.62 vs $105 for Claude Opus 4.6 (Fast), saving $104.38 (99.4% lower).
Mercury 2 is $104.38 cheaper on the standard workload (99.4% lower).
Mercury 2 is $29.75 cheaper per 1M input tokens (99.2% lower; 120x difference).
Mercury 2 is $149.25 cheaper per 1M output tokens (99.5% lower; 200x difference).
Claude Opus 4.6 (Fast) has 872K more context (7.81x larger).

Head-to-Head Specs

Feature	Claude Opus 4.6 (Fast) (Anthropic)	Mercury 2 (Inception)
Input Price prompt tokens per 1M	$30	$0.25
Completion Price per 1M tokens	$150	$0.75
Sample Workload Cost 1M input + 500K output	$105	$0.62
Context Window	1M	128K
Release Date	2026-04-07	2026-03-04

Use-Case Decision Matrix

Use case	Better pick	Why
Budget-constrained production	Mercury 2	On the standard 1M input plus 500K output workload, Mercury 2 is estimated at $0.62 vs $105 for Claude Opus 4.6 (Fast), saving $104.38 (99.4% lower).
High-volume input processing	Mercury 2	Lower prompt-token price matters most when prompts, retrieved passages, or documents dominate the bill.
Long responses and chatbots	Mercury 2	Lower output-token price matters most when assistants generate many completion tokens.
RAG or long-document work	Claude Opus 4.6 (Fast)	A larger context window leaves more room for retrieved passages, conversation history, or source files.

Related Alternatives

Same-provider lower-cost swaps

Claude 3 Haiku can replace Claude Opus 4.6 (Fast) when lower sample workload cost matters most: $0.88.
Claude 3.5 Haiku can replace Claude Opus 4.6 (Fast) when lower sample workload cost matters most: $2.8.
Anthropic Claude Haiku Latest can replace Claude Opus 4.6 (Fast) when lower sample workload cost matters most: $3.5.
Claude Haiku 4.5 can replace Claude Opus 4.6 (Fast) when lower sample workload cost matters most: $3.5.

Larger context near this budget

Llama 4 Scout offers 10M context with $0.23 sample workload cost.
Grok 4.20 Multi-Agent offers 2M context with $5 sample workload cost.
Grok 4.20 offers 2M context with $2.5 sample workload cost.
OpenAI GPT Latest offers 1.05M context with $20 sample workload cost.

Popular competitors

No popular competitor is currently available.

Cheaper alternatives

Review low-cost models sorted by a standard 1M input plus 500K output workload.

Open cheapest models

Larger context alternatives

Find models with larger context windows for RAG, long documents, and codebase review.

Open largest context models

Provider catalogs

Compare models within provider hubs before choosing a final API vendor.

Open provider hubs

Anthropic catalog

Review all tracked Anthropic models before deciding whether this matchup is the right shortlist.

Open Anthropic models

Inception catalog

Check other Inception models with comparable pricing, context, or release timing.

Open Inception models

Claude Opus 4.6 (Fast)

Fast-mode variant of [Opus 4.6](/anthropic/claude-opus-4.6) - identical capabilities with higher output speed at premium 6x pricing. Learn more in Anthropic's docs: https://platform.claude.com/docs/en/build-with-claude/fast-mode

Mercury 2

Mercury 2 is an extremely fast reasoning LLM, and the first reasoning diffusion LLM (dLLM). Instead of generating tokens sequentially, Mercury 2 produces and refines multiple tokens in parallel, achieving...