Verified 2026 API Rates • Prompt Caching & Batch ROI

Anthropic: Claude Fable 5.2 vs Google: Gemini 3.1 Flash Lite

Compare real-world API costs for Anthropic: Claude Fable 5.2 ($8/$40) vs Google: Gemini 3.1 Flash Lite ($0.25/$1.5). Calculate Prompt Caching ROI & Batch API savings.

Google: Gemini 3.1 Flash Lite saves up to 97% on base input tokens
Anthropic

Anthropic: Claude Fable 5.2

claude-fable-5.2
Base Input Rate
$8.00 / 1M
Output Rate
$40.00 / 1M
Prompt Cache Read
$0.20 / 1M (-97.5%)
Cache Write Surcharge
$10.00 / 1M (+25%)
Batch API Discount
-50% Off
Context Window
1,000k tokens
Quality Index (MMLU)
88
Google

Google: Gemini 3.1 Flash Lite

gemini-3.1-flash-lite
Base Input Rate
$0.25 / 1M
Output Rate
$1.50 / 1M
Prompt Cache Read
$0.025 / 1M (-90%)
Cache Write Surcharge
$0.00 (Free write)
Batch API Discount
-50% Off
Context Window
1,048.576k tokens
Quality Index (MMLU)
88
Differential Module 1

Prompt Caching ROI & Write Surcharge Break-Even Analysis

Prompt caching drastically reduces input token costs for static prefixes like system prompts, tool schemas, and document chunks. Compare caching mechanisms between Anthropic: Claude Fable 5.2 and Google: Gemini 3.1 Flash Lite:

Anthropic: Claude Fable 5.2 Caching Profile-97.5% read discount

  • Cached Read Price: $0.200 per 1M tokens.
  • Write Surcharge: $10.00/1M (+25% fee on initial cache write).
  • Minimum Cache Prefix: 1,024 tokens.
  • Amortization Rule: Net cost savings begin when prefix is reused > 1.25 times within TTL.

Google: Gemini 3.1 Flash Lite Caching Profile-90% read discount

  • Cached Read Price: $0.025 per 1M tokens.
  • Write Surcharge: $0.00 (automatic caching with zero write penalty).
  • Minimum Cache Prefix: 1,024 tokens.
  • Amortization Rule: Immediate net savings from first cached read call.
Differential Module 2

Batch API 50% Discount Offload vs Real-Time SLA

Asynchronous Batch APIs cut total token expenditures in half (50% off input and output) in exchange for non-realtime execution (up to 24-hour turnaround SLA).

Model / ArchitectureStandard Input / OutputBatch 50% Off Input / OutputTurnaround SLAOptimal Use Cases
Anthropic: Claude Fable 5.2$8.00 / $40.00$4.00 / $20.00 (-50%)24 Hours max (typically 30m - 2h)Bulk evaluation, dataset labeling, background summarization
Google: Gemini 3.1 Flash Lite$0.25 / $1.50$0.13 / $0.75 (-50%)24 Hours max (typically 30m - 2h)Offline document translation, embedding backfills, test suites
Differential Module 3

Context Window Escalation & Tiered Pricing Architecture

Massive context windows allow ingesting entire repositories or books, but pricing models differ drastically between flat-rate vendors and tiered step-up pricing.

Anthropic: Claude Fable 5.2 Context Capacity

Provides a 1,000k token context window with a maximum output limit of 128k tokens.✓ Flat-rate billing across all prompt sizes up to max context ceiling.

Google: Gemini 3.1 Flash Lite Context Capacity

Provides a 1,048.576k token context window with a maximum output limit of 65.536k tokens.✓ Flat-rate billing across all prompt sizes up to max context ceiling.

Quill Strategic Content

Real-World Production Scenarios: Monthly Spend Projections

Pre-computed monthly engineering bill projections across 3 representative enterprise application workloads:

Scenario 1

RAG Knowledge Base & Enterprise Search

100,000 queries/month, 3,500 input tokens (system + 5 retrieved chunks), 400 output tokens, 75% prompt cache hit rate.

Anthropic: Claude Fable 5.2:$2492.50/mo
Google: Gemini 3.1 Flash Lite:$88.44/mo
Delta Savings:-$2404.06 (96%)
Architecture Verdict:Google: Gemini 3.1 Flash Lite delivers 96% lower monthly spend ($2404.06/mo savings) for this workload profile.
Scenario 2

Multi-Turn Coding Agent & ReAct Loops

25,000 tasks/month, 8,000 input tokens (accumulating conversation context & tool schemas), 1,200 output tokens, 85% cache hit rate.

Anthropic: Claude Fable 5.2:$1437.45/mo
Google: Gemini 3.1 Flash Lite:$52.49/mo
Delta Savings:-$1384.96 (96%)
Architecture Verdict:Google: Gemini 3.1 Flash Lite delivers 96% lower monthly spend ($1384.96/mo savings) for this workload profile.
Scenario 3

High-Throughput Offline Data Extraction

500,000 records/month, 1,500 input tokens, 250 output tokens, 100% batch offload (24-hour turnaround SLA).

Anthropic: Claude Fable 5.2:$5065.00/mo
Google: Gemini 3.1 Flash Lite:$170.63/mo
Delta Savings:-$4894.38 (97%)
Architecture Verdict:Google: Gemini 3.1 Flash Lite delivers 97% lower monthly spend ($4894.38/mo savings) for this workload profile.
ミリ秒単位の対話型シミュレータ

Anthropic: Claude Fable 5.2 vs Google: Gemini 3.1 Flash Lite

エンタープライズの代表的な3大ユースケース(RAG検索、コーディングAgent、バッチ抽出)で精密試算:

Live 50ms Engine
月間リクエスト数 (Requests)100,000
入力トークン数/回 (Input Tokens)4,000
出力トークン数/回 (Output Tokens)1,000
Prompt キャッシュヒット率 (Cache Hit)70%
Batch API 分流比率0%
Google: Gemini 3.1 Flash Lite 安価

月間推定削減額

Anthropic: Claude Fable 5.2$5,176.00$51.760// 1,000リクエスト
vs
Google: Gemini 3.1 Flash Lite$187.00$1.870// 1,000リクエスト
Developer FAQs

Frequently Asked Questions: Anthropic: Claude Fable 5.2 vs Google: Gemini 3.1 Flash Lite

Authoritative answers on API rate limits, pricing math, break-even thresholds, and architectural migration.

1Which model is cheaper overall: Anthropic: Claude Fable 5.2 or Google: Gemini 3.1 Flash Lite?

At base pricing, Anthropic: Claude Fable 5.2 costs $8/1M input and $40/1M output, while Google: Gemini 3.1 Flash Lite costs $0.25/1M input and $1.5/1M output. The cheaper option depends on your input-to-output token ratio and whether prompt caching or batch discounts are utilized.

2How does Prompt Caching impact the cost of Anthropic: Claude Fable 5.2 vs Google: Gemini 3.1 Flash Lite?

Anthropic: Claude Fable 5.2 offers a 97.5% read discount ($0.2/1M), whereas Google: Gemini 3.1 Flash Lite provides a 90% read discount ($0.025/1M). High cache hit ratios (>70%) significantly compress the cost delta in agentic and RAG architectures.

3Can I use Batch API with Anthropic: Claude Fable 5.2 or Google: Gemini 3.1 Flash Lite to save 50%?

Anthropic: Claude Fable 5.2 supports 50% batch offload discounts for asynchronous 24-hour turnaround tasks. Google: Gemini 3.1 Flash Lite supports 50% batch discounts.

4What are the context window limits and tiered pricing rules for Anthropic: Claude Fable 5.2 vs Google: Gemini 3.1 Flash Lite?

Anthropic: Claude Fable 5.2 features a 1,000k context window with flat per-token pricing. In comparison, Google: Gemini 3.1 Flash Lite supports 1,048.576k tokens with flat per-token pricing.