Verified 2026 API Rates • Prompt Caching & Batch ROI

Gemini 1.5 Flash vs Google: Gemini 4 Hydrogen

Compare real-world API costs for Gemini 1.5 Flash ($0.075/$0.3) vs Google: Gemini 4 Hydrogen ($1.5/$7.5). Calculate Prompt Caching ROI & Batch API savings.

Gemini 1.5 Flash saves up to 95% on base input tokens
Google

Gemini 1.5 Flash

gemini-1.5-flash
Base Input Rate
$0.07 / 1M
Output Rate
$0.30 / 1M
Prompt Cache Read
$0.019 / 1M (-75%)
Cache Write Surcharge
$0.00 (Free write)
Batch API Discount
-50% Off
Context Window
1,000k tokens
Quality Index (MMLU)
78.9
Google

Google: Gemini 4 Hydrogen

gemini-4-hydrogen
Base Input Rate
$1.50 / 1M
Output Rate
$7.50 / 1M
Prompt Cache Read
$0.075 / 1M (-95%)
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 Gemini 1.5 Flash and Google: Gemini 4 Hydrogen:

Gemini 1.5 Flash Caching Profile-75% read discount

  • Cached Read Price: $0.019 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.

Google: Gemini 4 Hydrogen Caching Profile-95% read discount

  • Cached Read Price: $0.075 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
Gemini 1.5 Flash$0.07 / $0.30$0.04 / $0.15 (-50%)24 Hours max (typically 30m - 2h)Bulk evaluation, dataset labeling, background summarization
Google: Gemini 4 Hydrogen$1.50 / $7.50$0.75 / $3.75 (-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.

Gemini 1.5 Flash Context Capacity

Provides a 1,000k token context window with a maximum output limit of 8.192k tokens.⚠️ Note: Prompts exceeding 128k tokens double in price to $0.15/1M in and $0.6/1M out.

Google: Gemini 4 Hydrogen Context Capacity

Provides a 1,048.576k token context window with a maximum output limit of 943.718k 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.

Gemini 1.5 Flash:$23.48/mo
Google: Gemini 4 Hydrogen:$450.94/mo
Delta Savings:-$427.45 (95%)
Architecture Verdict:Gemini 1.5 Flash delivers 95% lower monthly spend ($427.45/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.

Gemini 1.5 Flash:$13.35/mo
Google: Gemini 4 Hydrogen:$261.54/mo
Delta Savings:-$248.19 (95%)
Architecture Verdict:Gemini 1.5 Flash delivers 95% lower monthly spend ($248.19/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).

Gemini 1.5 Flash:$42.66/mo
Google: Gemini 4 Hydrogen:$924.38/mo
Delta Savings:-$881.72 (95%)
Architecture Verdict:Gemini 1.5 Flash delivers 95% lower monthly spend ($881.72/mo savings) for this workload profile.
毫秒級即時互動模擬引擎

Gemini 1.5 Flash 對比 Google: Gemini 4 Hydrogen

針對企業典型三大工程落地形態(RAG 知識庫、Coding Agent 多輪、離線批次清洗)進行精確成本演算:

Live 50ms Engine
月度請求量 (Requests)100,000
單次輸入代幣 (Input Tokens)4,000
單次輸出代幣 (Output Tokens)1,000
Prompt 快取命中率 (Cache Hit)70%
Batch API 批次分流比例0%
Gemini 1.5 Flash 更便宜

預計每月節省

Gemini 1.5 Flash$44.25$0.442// 千次請求
對比
Google: Gemini 4 Hydrogen$951.00$9.510// 千次請求
Developer FAQs

Frequently Asked Questions: Gemini 1.5 Flash vs Google: Gemini 4 Hydrogen

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

1Which model is cheaper overall: Gemini 1.5 Flash or Google: Gemini 4 Hydrogen?

At base pricing, Gemini 1.5 Flash costs $0.075/1M input and $0.3/1M output, while Google: Gemini 4 Hydrogen costs $1.5/1M input and $7.5/1M 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 Gemini 1.5 Flash vs Google: Gemini 4 Hydrogen?

Gemini 1.5 Flash offers a 75% read discount ($0.01875/1M), whereas Google: Gemini 4 Hydrogen provides a 95% read discount ($0.075/1M). High cache hit ratios (>70%) significantly compress the cost delta in agentic and RAG architectures.

3Can I use Batch API with Gemini 1.5 Flash or Google: Gemini 4 Hydrogen to save 50%?

Gemini 1.5 Flash supports 50% batch offload discounts for asynchronous 24-hour turnaround tasks. Google: Gemini 4 Hydrogen supports 50% batch discounts.

4What are the context window limits and tiered pricing rules for Gemini 1.5 Flash vs Google: Gemini 4 Hydrogen?

Gemini 1.5 Flash features a 1,000k context window with tiered escalation above 128k tokens. In comparison, Google: Gemini 4 Hydrogen supports 1,048.576k tokens with flat per-token pricing.