Last verified 2025-09-22 (left) · 2025-09-22 (right)

Claude Opus 4.1 (Legacy) vs Gemini 2.5 Flash-Lite — Pricing & Capability Comparison

Claude Opus 4.1 (Legacy) charges $15.00 per million input tokens and $75.00 per million output tokens. Gemini 2.5 Flash-Lite comes in at $0.10 / $0.40. Context windows span 200K vs 1M tokens respectively.

TL;DR — Quick Comparison

✓Gemini 2.5 Flash-Lite is cheaper overall: $0.50 per 1M tokens (in+out) vs $90.00 for Claude Opus 4.1 (Legacy) — saves $89.50 per 1M tokens
✓Input pricing: Claude Opus 4.1 (Legacy) $15.00/1M vs Gemini 2.5 Flash-Lite $0.10/1M
✓Output pricing: Claude Opus 4.1 (Legacy) $75.00/1M vs Gemini 2.5 Flash-Lite $0.40/1M
✓Context window: Gemini 2.5 Flash-Lite offers more (1M vs 200K)
✓Use our calculator below to estimate costs for your specific usage pattern

Input price (per 1M)

Claude Opus 4.1 (Legacy)

$15.00

Gemini 2.5 Flash-Lite

$0.10

Gemini 2.5 Flash-Lite leads here

Output price (per 1M)

Claude Opus 4.1 (Legacy)

$75.00

Gemini 2.5 Flash-Lite

$0.40

Gemini 2.5 Flash-Lite leads here

Context window

Claude Opus 4.1 (Legacy)

200,000 tokens

Gemini 2.5 Flash-Lite

1,000,000 tokens

Gemini 2.5 Flash-Lite leads here

Cached input

Claude Opus 4.1 (Legacy)

Not published

Gemini 2.5 Flash-Lite

Not published

No published data

Which one should you choose?

Skip the spreadsheet if you just need the practical takeaway. Use these rules when deciding between Claude Opus 4.1 (Legacy) and Gemini 2.5 Flash-Lite.

Choose Gemini 2.5 Flash-Lite if input tokens dominate your bill

Gemini 2.5 Flash-Lite has the lower input rate, which usually matters most for chat, RAG, classification, and long-prompt workflows where prompt volume stays much larger than generated output.

Choose Gemini 2.5 Flash-Lite if you generate long answers

Gemini 2.5 Flash-Lite is cheaper on output tokens, so it tends to win for report generation, coding assistance, reasoning traces, and any workflow where completions are long.

Choose Gemini 2.5 Flash-Lite if context size is the blocker

Gemini 2.5 Flash-Lite offers the larger published context window, which is more important than small pricing differences when you need to fit large files, long chats, or multi-document prompts into one request.

Cost comparison for 10K-token workloads

Side-by-side pricing for identical workloads (10,000 total tokens per request) across different distributions.

Scenario	Claude Opus 4.1 (Legacy)	Gemini 2.5 Flash-Lite
Balanced conversation 50% input · 50% output	$0.450	$0.0025
Input-heavy workflow 80% input · 20% output	$0.270	$0.0016
Generation heavy 30% input · 70% output	$0.570	$0.0031
Cached system prompt 90% cached input · 10% fresh output	$0.210	$0.0013

Frequently asked questions

Which is cheaper: Claude Opus 4.1 (Legacy) or Gemini 2.5 Flash-Lite?

Gemini 2.5 Flash-Lite is cheaper for input tokens at $0.10 per 1M tokens compared to $15.00. For output, Gemini 2.5 Flash-Lite costs $0.40 per 1M tokens versus $75.00 for Claude Opus 4.1 (Legacy).

What is the cost per 1M tokens for Claude Opus 4.1 (Legacy)?

Claude Opus 4.1 (Legacy) pricing: $15.00 per 1M input tokens and $75.00 per 1M output tokens. Context window: 200,000 tokens.

What is the cost per 1M tokens for Gemini 2.5 Flash-Lite?

Gemini 2.5 Flash-Lite pricing: $0.10 per 1M input tokens and $0.40 per 1M output tokens. Context window: 1,000,000 tokens.

How much does it cost per 1K tokens?

Per 1K tokens: Claude Opus 4.1 (Legacy) costs $0.0150 input / $0.0750 output. Gemini 2.5 Flash-Lite costs $0.0001 input / $0.0004 output. This is useful for calculating small-scale usage costs.

Which model supports a larger context window?

Gemini 2.5 Flash-Lite offers 1,000,000 tokens (1M) versus 200K for Claude Opus 4.1 (Legacy).

What is the estimated monthly cost for typical usage?

For a typical workload of 10M input + 2M output tokens per month: Claude Opus 4.1 (Legacy) would cost approximately $300.00, while Gemini 2.5 Flash-Lite would cost $1.80. Gemini 2.5 Flash-Lite is more economical for this usage pattern.

Do these models support prompt caching?

Claude Opus 4.1 (Legacy) does not publish cached pricing. Gemini 2.5 Flash-Lite does not publish cached pricing.

Which model is best for my use case?

Choose Gemini 2.5 Flash-Lite for cost-sensitive applications with high input volume. Choose Gemini 2.5 Flash-Lite if you need 1M context for long documents or conversations. Consider prompt caching if you have repeated context. Use our token calculator to model your specific usage pattern.