API cost decision in 10 seconds

Grok 4.20 Multi-Agent vs Gemini 3.1 Pro Preview Custom Tools

Pick Grok 4.20 Multi-Agent when budget and context both matter.

Page updated:  Data confirmed:  Prices normalized to USD per 1M tokens Sample workload: 1M input + 500K output

Budget verdict

Pick Grok 4.20 Multi-Agent when budget and context both matter.

On the standard 1M input plus 500K output workload, Grok 4.20 Multi-Agent is estimated at $5 vs $8 for Gemini 3.1 Pro Preview Custom Tools, saving $3 (37.5% lower).

Cost-first pickGrok 4.20 Multi-Agent
Context-first pickGrok 4.20 Multi-Agent
Sample savings$337.5%
10x traffic gap$30

Grok 4.20 Multi-Agent is cheaper on the standard workload and also has the larger context window. At 10x that traffic, the same price gap is about $30. Use the calculator below to replace the sample workload with your own token volume.

Cost sensitivity

Workload Sensitivity

Same prices, different token mixes.

Grok 4.20 Multi-Agent stays cheaper across input-heavy, balanced, and output-heavy sample workloads.

Workload shapeToken mixBetter pickGrok 4.20 Multi-AgentGemini 3.1 Pro Preview Custom Tools
Input-heavy / RAG5M input + 500K outputGrok 4.20 Multi-Agent$13$16
Balanced workload1M input + 1M outputGrok 4.20 Multi-Agent$8$14
Output-heavy chatbot1M input + 5M outputGrok 4.20 Multi-Agent$32$62
Cheaper input Tie $2 vs $2 / 1M

Both models report the same input price at $2 per 1M tokens.

Cheaper output Grok 4.20 Multi-Agent $6 vs $12 / 1M

Grok 4.20 Multi-Agent is $6 cheaper per 1M output tokens (50% lower; 2x difference).

Larger context Grok 4.20 Multi-Agent 2M vs 1.05M

Grok 4.20 Multi-Agent has 951.24K more context (1.91x larger).

Sample workload Grok 4.20 Multi-Agent $5 vs $8

Grok 4.20 Multi-Agent is $3 cheaper on the standard workload (37.5% lower).

Estimate your workload cost

Your Workload Cost

Prices are normalized to USD per 1M tokens.
Grok 4.20 Multi-Agent Calculating… Estimated API cost
Gemini 3.1 Pro Preview Custom Tools 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

both models tie on input price; Grok 4.20 Multi-Agent has the lower output price; Grok 4.20 Multi-Agent offers the larger context window. For the 1M input plus 500K output sample, Grok 4.20 Multi-Agent is cheaper for the standard workload.

For a 1M input token plus 500K output token workload, the estimated API cost is $5 for Grok 4.20 Multi-Agent and $8 for Gemini 3.1 Pro Preview Custom Tools.

Best Fit

Choose Grok 4.20 Multi-Agent when you care most about lower output-token price, and larger context window.

Choose Gemini 3.1 Pro Preview Custom Tools when its provider, model quality, latency, or availability is more important than the numeric price/context winner.

Decision Notes
  • On the standard 1M input plus 500K output workload, Grok 4.20 Multi-Agent is estimated at $5 vs $8 for Gemini 3.1 Pro Preview Custom Tools, saving $3 (37.5% lower).
  • Grok 4.20 Multi-Agent is $3 cheaper on the standard workload (37.5% lower).
  • Both models report the same input price at $2 per 1M tokens.
  • Grok 4.20 Multi-Agent is $6 cheaper per 1M output tokens (50% lower; 2x difference).
  • Grok 4.20 Multi-Agent has 951.24K more context (1.91x larger).
Head-to-Head Specs
FeatureGrok 4.20 Multi-Agent
(xAI)		Gemini 3.1 Pro Preview Custom Tools
(Google)
Input Price
prompt tokens per 1M		$2$2
Completion Price
per 1M tokens		$6$12
Sample Workload Cost
1M input + 500K output		$5$8
Context Window2M1.05M
Release Date

Use-Case Decision Matrix

Use caseBetter pickWhy
Budget-constrained productionGrok 4.20 Multi-AgentOn the standard 1M input plus 500K output workload, Grok 4.20 Multi-Agent is estimated at $5 vs $8 for Gemini 3.1 Pro Preview Custom Tools, saving $3 (37.5% lower).
High-volume input processingTieLower prompt-token price matters most when prompts, retrieved passages, or documents dominate the bill.
Long responses and chatbotsGrok 4.20 Multi-AgentLower output-token price matters most when assistants generate many completion tokens.
RAG or long-document workGrok 4.20 Multi-AgentA larger context window leaves more room for retrieved passages, conversation history, or source files.

Related Alternatives

Same-provider lower-cost swaps
  • Grok Build 0.1 can replace Grok 4.20 Multi-Agent when lower sample workload cost matters most: $2.
  • Grok 4.3 can replace Grok 4.20 Multi-Agent when lower sample workload cost matters most: $2.5.
  • Grok 4.20 can replace Grok 4.20 Multi-Agent when lower sample workload cost matters most: $2.5.
  • Gemma 4 26B A4B (free) can replace Gemini 3.1 Pro Preview Custom Tools when lower sample workload cost matters most: $0.
Larger context near this budget
  • Llama 4 Scout offers 10M context with $0.23 sample workload cost.

Cheaper alternatives

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

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Larger context alternatives

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

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Provider catalogs

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xAI catalog

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

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Google catalog

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

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Grok 4.20 Multi-Agent

Grok 4.20 Multi-Agent is a variant of xAI’s Grok 4.20 designed for collaborative, agent-based workflows. Multiple agents operate in parallel to conduct deep research, coordinate tool use, and synthesize information...

Gemini 3.1 Pro Preview Custom Tools

Gemini 3.1 Pro Preview Custom Tools is a variant of Gemini 3.1 Pro that improves tool selection behavior by preventing overuse of a general bash tool when more efficient third-party...