API cost decision in 10 seconds

NewMercury 2.5 Preview vs Fugu Ultra

Pick Mercury 2.5 Preview for lower cost; pick Fugu Ultra only if the larger context window matters more.

Page updated: 2026-09-01T15:07:22Z Data confirmed: 2026-09-01T17:07:29Z Prices normalized to USD per 1M tokens Sample workload: 1M input + 500K output

Budget verdict

Pick Mercury 2.5 Preview for lower cost; pick Fugu Ultra only if the larger context window matters more.

On the standard 1M input plus 500K output workload, Mercury 2.5 Preview is estimated at $0.11 vs $20 for Fugu Ultra, saving $19.89 (99.4% lower).

Cost-first pickMercury 2.5 Preview

Context-first pickFugu Ultra

Sample savings$19.8999.4%

10x traffic gap$198.85

Fugu Ultra has more context, but Mercury 2.5 Preview saves $19.89 on the standard workload. At 10x that traffic, the same price gap is about $198.85. Use the calculator below to replace the sample workload with your own token volume.

Cost sensitivity

Workload Sensitivity

Same prices, different token mixes.

Mercury 2.5 Preview stays cheaper across input-heavy, balanced, and output-heavy sample workloads.

Workload shape	Token mix	Better pick	Mercury 2.5 Preview	Fugu Ultra
Input-heavy / RAG	5M input + 500K output	Mercury 2.5 Preview	$0.28	$40
Balanced workload	1M input + 1M output	Mercury 2.5 Preview	$0.19	$35
Output-heavy chatbot	1M input + 5M output	Mercury 2.5 Preview	$0.79	$155

Cheaper input Mercury 2.5 Preview $0.04 vs $5 / 1M

Mercury 2.5 Preview is $4.96 cheaper per 1M input tokens (99.2% lower; 125x difference).

Cheaper output Mercury 2.5 Preview $0.15 vs $30 / 1M

Mercury 2.5 Preview is $29.85 cheaper per 1M output tokens (99.5% lower; 200x difference).

Larger context Fugu Ultra 260K vs 1M

Fugu Ultra has 740K more context (3.85x larger).

Sample workload Mercury 2.5 Preview $0.11 vs $20

Mercury 2.5 Preview is $19.89 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

Mercury 2.5 Preview Calculating… Estimated API cost

Fugu Ultra 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 2.5 Preview has the lower input price; Mercury 2.5 Preview has the lower output price; Fugu Ultra offers the larger context window. For the 1M input plus 500K output sample, Mercury 2.5 Preview is cheaper for the standard workload.

For a 1M input token plus 500K output token workload, the estimated API cost is $0.11 for Mercury 2.5 Preview and $20 for Fugu Ultra.

Best Fit

Choose Mercury 2.5 Preview when you care most about lower input-token price, and lower output-token price.

Choose Fugu Ultra when you care most about larger context window.

Decision Notes

On the standard 1M input plus 500K output workload, Mercury 2.5 Preview is estimated at $0.11 vs $20 for Fugu Ultra, saving $19.89 (99.4% lower).
Mercury 2.5 Preview is $19.89 cheaper on the standard workload (99.4% lower).
Mercury 2.5 Preview is $4.96 cheaper per 1M input tokens (99.2% lower; 125x difference).
Mercury 2.5 Preview is $29.85 cheaper per 1M output tokens (99.5% lower; 200x difference).
Fugu Ultra has 740K more context (3.85x larger).

Head-to-Head Specs

Feature	NewMercury 2.5 Preview (Inception)	Fugu Ultra (Sakana)
Input Price prompt tokens per 1M	$0.04	$5
Completion Price per 1M tokens	$0.15	$30
Sample Workload Cost 1M input + 500K output	$0.11	$20
Context Window	260K	1M
Release Date	2026-08-31	2026-06-24

Use-Case Decision Matrix

Use case	Better pick	Why
Budget-constrained production	Mercury 2.5 Preview	On the standard 1M input plus 500K output workload, Mercury 2.5 Preview is estimated at $0.11 vs $20 for Fugu Ultra, saving $19.89 (99.4% lower).
High-volume input processing	Mercury 2.5 Preview	Lower prompt-token price matters most when prompts, retrieved passages, or documents dominate the bill.
Long responses and chatbots	Mercury 2.5 Preview	Lower output-token price matters most when assistants generate many completion tokens.
RAG or long-document work	Fugu Ultra	A larger context window leaves more room for retrieved passages, conversation history, or source files.

Related Alternatives

Same-provider lower-cost swaps

Sakana Namazu can replace Fugu Ultra when lower sample workload cost matters most: $2.95.

Larger context near this budget

Grok 4.20 Multi-Agent offers 2M context with $2.5 sample workload cost.
Grok 4.20 offers 2M context with $2.5 sample workload cost.
DeepSeek V4 Flash 0731 offers 1.31M context with $0.15 sample workload cost.
GLM 5.3 Flash offers 1.31M context with $0.2 sample workload cost.

Popular competitors

DeepSeek V4 Flash 0731 · DeepSeek · #1
GPT-5.6 Luna · OpenAI · #2
GLM 5.3 Flash · Z.ai · #3
MiMo-V2.5 · Xiaomi · #4

Cheaper alternatives

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Larger context alternatives

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Provider catalogs

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Inception catalog

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Sakana catalog

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

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Mercury 2.5 Preview

Mercury 2.5 is the fastest reasoning LLM, and the latest diffusion LLM (dLLM) from Inception. Instead of generating tokens sequentially, Mercury 2.5 produces and refines multiple tokens in parallel, achieving...

Fugu Ultra

Fugu Ultra is the higher-performance model in Sakana AI's Fugu family. Rather than a single monolithic model, Fugu is a learned multi-agent orchestration system: a language model trained to route...