Model comparison

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Mercury 2.5 vs Gemini 3.5 Flash Lite

Inception against Google AI, compared on listed price, real workload cost, context and capabilities.

The short answer

  • Mercury 2.5 lists lower input and output prices.
  • Gemini 3.5 Flash Lite offers the larger context window.
  • Gemini 3.5 Flash Lite supports vision; Mercury 2.5 does not.
  • Mercury 2.5 reads cached input for less ($0.02/M against Gemini 3.5 Flash Lite's $0.03/M), which decides the bill for agents that resend long context.

Side-by-side specs

SpecMercury 2.5Gemini 3.5 Flash Lite
ProviderInceptionGoogle AI
Input price$0.2/M$0.3/M
Output price$0.75/M$2.5/M
Cached input$0.02/M$0.03/M
Blended price (3:1)$0.338/M$0.85/M
Context window260k tokens1M tokens
Max output65.536k tokens65.536k tokens
InputTextText, Images, Video, Audio, PDF
Structured outputYesYes
WeightsClosedClosed
ReleasedSeptember 2026July 21, 2026
AvailabilityRetires 4 November 2026Live

Same work, both models

WorkloadMercury 2.5Gemini 3.5 Flash Lite
One chat reply3,000 tokens in, 500 outGemini 3.5 Flash Lite costs 2.2× as much as Mercury 2.5$0.00098$0.0022
Summarise a 100-page report50,000 tokens in, 1,500 out, one requestGemini 3.5 Flash Lite costs 1.7× as much as Mercury 2.5$0.01$0.02
1,000 classification calls500 tokens in, 20 out, per call$0.12$0.20
Coding-agent session2M tokens in across ~60 turns, 60,000 out, no cache$0.45$0.75
Same session, cached85% of input read from the prompt cache, the rest written to itGemini 3.5 Flash Lite costs 2.1× as much as Mercury 2.5$0.14$0.29

At listed rates. Token counts are typical sizes, not measurements.

Mercury 2.5 pricing notes

  • The 80% launch rate ($0.04 / $0.15) has ended; the listed price is Inception's standard rate.
  • Prompt caching is automatic; cached input bills at $0.02 per 1M tokens.

Gemini 3.5 Flash Lite pricing notes

  • Rates are flat at every context length; no long-context surcharge applies.
  • Thinking tokens bill as output; it defaults to minimal thinking, with low, medium and high available.

When to pick which

Mercury 2.5

Inception's previous-generation diffusion LLM from September 2026, text-only, with tunable reasoning and a 260K context window. It retires on 2026-11-04; Mercury 3, the current generation, has lower input and output rates.

Pick it if

  • you need fast text generation with reasoning and schema-aligned JSON
  • your prompts repeat, so cached input bills at a tenth of input

Skip it if

  • Mercury 3 costs less on both rates and has a 1M window
  • you need image input

Gemini 3.5 Flash Lite

Google's Flash-Lite tier Gemini model for high-volume agentic work, subagent tasks, document parsing and simple data extraction. It is the cheapest Gemini in the catalog, and Google positions it as a replacement for Gemini 2.5 Flash.

Pick it if

  • you want the cheapest Gemini in the catalog for high-volume calls
  • you send images, video, audio or PDFs alongside text
  • you resend long prompts; cache hits bill at 10% of input

Skip it if

  • your coding work goes beyond the simple tasks Google targets
  • you need image or audio output; it returns text only

FAQ

Which is cheaper, Mercury 2.5 or Gemini 3.5 Flash Lite?

Mercury 2.5 lists lower input and output prices. On a coding-agent session (2M tokens in, 60,000 out) Mercury 2.5 costs $0.45 and Gemini 3.5 Flash Lite $0.75.

Which has the larger context window?

Gemini 3.5 Flash Lite offers the larger context window. Mercury 2.5: 260k tokens; Gemini 3.5 Flash Lite: 1M tokens.

Which one accepts images?

Gemini 3.5 Flash Lite supports vision; Mercury 2.5 does not.

Can I switch between Mercury 2.5 and Gemini 3.5 Flash Lite mid-task?

Yes. In an Octomind session, /model octohub:mercury-2.5 and /model octohub:gemini-3.5-flash-lite switch models without losing the conversation, so you can draft on one and review on the other.

Try either model

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Prices from the catalog of 2026-10-28