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Kimi K2 Instruct (Fireworks) vs Nano Banana 2 (Gemini 3.1 Flash Image): API Cost Comparison

Compare the API pricing, context windows, features, and real-world cost projections for Kimi K2 Instruct (Fireworks) (Fireworks AI) and Nano Banana 2 (Gemini 3.1 Flash Image) (Google). Use the interactive calculator below to compute your exact monthly cost based on your token usage and request volume.

Prices verified Jun 26, 2026

Interactive Cost Calculator

Fireworks AIKimi K2 Instruct (Fireworks)GoogleNano Banana 2 (Gemini 3.1 Flash Image)

Fills in typical token counts for a workload type

Tokens in each prompt sent to the model

Tokens generated in each response

Total API calls per month

Showing costs for 2 models. Cheapest: Kimi K2 Instruct (Fireworks) at $18.50/month.

Cheapest: Kimi K2 Instruct (Fireworks) at $18.50/mo — save 7.5% vs Nano Banana 2 (Gemini 3.1 Flash Image)
Alert
BestKimi K2 Instruct (Fireworks)
Fireworks AI$18.50$0.001850$6.00$12.507.5%Alerts coming soon
Nano Banana 2 (Gemini 3.1 Flash Image)
Google$20.00$0.002000$5.00$15.00Alerts coming soon

Monthly Cost Comparison

Price Comparison at a Glance

All prices are in USD per 1 million tokens ($/M tokens). Lower is cheaper.

Pricing TypeKimi K2 Instruct (Fireworks)Nano Banana 2 (Gemini 3.1 Flash Image)Cheaper
Input (standard)$0.60/M$0.50/MNano Banana 2 (Gemini 3.1 Flash Image)
Output$2.50/M$3.00/MKimi K2 Instruct (Fireworks)
Cached input$0.30/MN/A
Batch input$0.30/MN/A
Batch output$1.25/MN/A

Prices last verified: 2026-03-10 – 2026-06-26

Cost Breakdown by Usage Volume

Estimated monthly costs at different request volumes, assuming 1,000 input tokens and 500 output tokens per request. Adjust in the calculator above for your specific use case.

VolumeKimi K2 Instruct (Fireworks)MonthlyNano Banana 2 (Gemini 3.1 Flash Image)MonthlyKimi K2 Instruct (Fireworks)Per requestNano Banana 2 (Gemini 3.1 Flash Image)Per request
1K requests/mo$1.85$2.00$0.001850$0.002000
10K requests/mo$18.50$20.00$0.001850$0.002000
100K requests/mo$185.00$200.00$0.001850$0.002000
1M requests/mo$1,850.00$2,000.00$0.001850$0.002000

Green values indicate the lower-cost option at each volume tier. Cost per request is calculated at 1,000 input + 500 output tokens using standard (non-batch, non-cached) pricing.

Price History

Input price per 1M tokens

When to Choose Kimi K2 Instruct (Fireworks)

by Fireworks AI

  • Code generation
  • Document summarization
  • RAG / Semantic search

Input / 1M tokens

$0.60/M

Output / 1M tokens

$2.50/M

Context window

131,072

Tier

mid

When to Choose Nano Banana 2 (Gemini 3.1 Flash Image)

by Google

  • General chatbot

Input / 1M tokens

$0.50/M

Output / 1M tokens

$3.00/M

Context window

131,072

Tier

budget

Key Differences Beyond Price

Cost is only one factor in choosing an AI model. Context window size, rate limits, supported features, and latency all affect whether a model fits your use case.

CapabilityKimi K2 Instruct (Fireworks)Nano Banana 2 (Gemini 3.1 Flash Image)
Context window131,072 tokens131,072 tokens
Max output tokens16,384 tokens32,768 tokens
Performance tierMidBudget
Vision / image inputNoYes
Function callingYesNo
JSON modeYesYes
Prompt cachingYesNo
Batch API (50% discount)YesNo
Extended reasoningNoYes
Fine-tuningNoNo

Kimi K2 Instruct (Fireworks) notes

Fireworks serverless pricing. Cached input 50% discount. Batch at 50% of serverless.

Frequently Asked Questions

Is Kimi K2 Instruct (Fireworks) cheaper than Nano Banana 2 (Gemini 3.1 Flash Image)?

At standard usage (1,000 input tokens, 500 output tokens, 100,000 requests/month), Kimi K2 Instruct (Fireworks) costs $185.00/month versus $200.00/month for Nano Banana 2 (Gemini 3.1 Flash Image) — a 8% saving. Your actual savings will vary based on your token profile; output-heavy workloads amplify differences in output pricing.

Which model has a larger context window, Kimi K2 Instruct (Fireworks) or Nano Banana 2 (Gemini 3.1 Flash Image)?

Both Kimi K2 Instruct (Fireworks) and Nano Banana 2 (Gemini 3.1 Flash Image) have the same context window: 131,072 tokens.

Do Kimi K2 Instruct (Fireworks) and Nano Banana 2 (Gemini 3.1 Flash Image) support the Batch API?

Kimi K2 Instruct (Fireworks) supports the Batch API (50% discount for async processing), while Nano Banana 2 (Gemini 3.1 Flash Image) does not. If your workload tolerates up to 24-hour latency, routing to Kimi K2 Instruct (Fireworks) with batch pricing could significantly cut costs versus Nano Banana 2 (Gemini 3.1 Flash Image)'s standard rate.

Which model offers better prompt caching?

Kimi K2 Instruct (Fireworks) supports prompt caching at $0.30/M for cached input, while Nano Banana 2 (Gemini 3.1 Flash Image) does not offer prompt caching. For RAG applications or chatbots with large, repeated context, Kimi K2 Instruct (Fireworks)'s caching capability can substantially reduce effective costs.

What are the best use cases for Kimi K2 Instruct (Fireworks) vs Nano Banana 2 (Gemini 3.1 Flash Image)?

Kimi K2 Instruct (Fireworks) is best suited for Code generation, Document summarization, RAG / Semantic search, while Nano Banana 2 (Gemini 3.1 Flash Image) is optimized for General chatbot. Choose based on which use case matches your primary workload — and validate with the cost calculator above to confirm the total monthly spend fits your budget.

What is the cost per request for Kimi K2 Instruct (Fireworks) vs Nano Banana 2 (Gemini 3.1 Flash Image)?

At 1,000 input tokens and 500 output tokens per request — a typical conversational workload — Kimi K2 Instruct (Fireworks) costs $0.001850 per request and Nano Banana 2 (Gemini 3.1 Flash Image) costs $0.002000 per request. At 100,000 requests/month, that translates to $185.00 and $200.00 respectively. Use the interactive calculator to adjust these parameters for your actual workload.

Kimi K2 Instruct (Fireworks) vs Nano Banana 2 (Gemini 3.1 Flash Image): Summary

When comparing Kimi K2 Instruct (Fireworks) and Nano Banana 2 (Gemini 3.1 Flash Image) for API cost, the right choice depends on your workload's token profile, required features, and tolerance for latency. Kimi K2 Instruct (Fireworks) offers lower total cost at standard usage volumes (1,000 input + 500 output tokens per request at 100,000 requests/month) at $185.00/month, compared to $200.00/month for Nano Banana 2 (Gemini 3.1 Flash Image).

Both models are priced in USD per million tokens, the standard unit across all major AI API providers. Kimi K2 Instruct (Fireworks) charges $0.60/M for input tokens and $2.50/M for output tokens. Nano Banana 2 (Gemini 3.1 Flash Image) charges $0.50/M input and $3.00/M output. If your workload is output-heavy (more tokens generated than consumed as input), the model with the lower output price compounds cost savings significantly at scale.

Prompt caching is supported by Kimi K2 Instruct (Fireworks) but not Nano Banana 2 (Gemini 3.1 Flash Image). For workloads with large, repeated system prompts or document context — such as RAG pipelines or multi-turn conversations with a fixed knowledge base — prompt caching can reduce effective input costs by 60–90%, which may change the cost ranking between these two models at your specific usage pattern.

Context window capacity differs between the two: Both models support 131,072 tokens per request. A larger context window is essential for document summarization, large codebase analysis, and multi-document retrieval-augmented generation (RAG) applications.

Use the interactive calculator at the top of this page to enter your actual token usage and monthly request volume for a precise cost comparison tailored to your workload. Adjust for batch API discounts and prompt caching to find the most cost-effective option for your specific deployment.

Explore other model comparisons from the same providers or performance tiers.

Related Provider Pages

View complete pricing tables and model lineups for the providers behind these models.

Relevant Use Cases

See cost recommendations for workloads where Kimi K2 Instruct (Fireworks) or Nano Banana 2 (Gemini 3.1 Flash Image) is recommended.