LLM Reference

Gemini 3.1 Flash-Lite vs GPT-5.5 Instant

Gemini 3.1 Flash-Lite (2026) and GPT-5.5 Instant (2026) are general-purpose language models from Google DeepMind and OpenAI. Gemini 3.1 Flash-Lite ships a 1.05m-token context window, while GPT-5.5 Instant ships a 400k-token context window. On MMMU Pro, Gemini 3.1 Flash-Lite leads by 0.8 pts. On pricing, Gemini 3.1 Flash-Lite costs $0.25/1M input tokens versus $5/1M for the alternative. This comparison covers specs, pricing, API access, capabilities, benchmarks, input and output token costs, and production fit for coding and agent workloads.

Gemini 3.1 Flash-Lite is ~1900% cheaper at $0.25/1M; pay for GPT-5.5 Instant only for coding workflow support.

Decision scorecard

Local evidence first
SignalGemini 3.1 Flash-LiteGPT-5.5 Instant
Best formultimodal apps, tool-calling agents, and long-context analysismultimodal apps and tool-calling agents
Decision fitCoding, RAG, and AgentsCoding, RAG, and Agents
Context window1.05m400k
Cheapest output$1.50/1M tokens$30/1M tokens
Provider routes3 tracked1 tracked
Shared benchmarksMMMU Pro leader1 shared

Decision tradeoffs

Choose Gemini 3.1 Flash-Lite when...
  • Gemini 3.1 Flash-Lite holds a shared-benchmark lead on MMMU Pro, ahead by 0.8 points.
  • Gemini 3.1 Flash-Lite has the larger context window for long prompts, retrieval packs, or transcript analysis.
  • Gemini 3.1 Flash-Lite has the lower cheapest tracked output price at $1.50/1M tokens.
  • Gemini 3.1 Flash-Lite has broader tracked provider coverage for fallback and route flexibility.
  • Local decision data tags Gemini 3.1 Flash-Lite for Coding, RAG, and Agents.
Choose GPT-5.5 Instant when...
  • Local decision data tags GPT-5.5 Instant for Coding, RAG, and Agents.

Monthly cost at traffic

Estimate token spend from the cheapest tracked input and output route or tier on this page.

Lower estimate Gemini 3.1 Flash-Lite

Gemini 3.1 Flash-Lite

$575

Cheapest tracked route/tier: Google AI Studio

GPT-5.5 Instant

$11,500

Cheapest tracked route/tier: OpenAI API

Estimated monthly gap: $10,925. Batch, cache, alternate speed tiers, and negotiated pricing are excluded from this local estimate.

Switch friction

Gemini 3.1 Flash-Lite -> GPT-5.5 Instant
  • No overlapping tracked provider route is sourced for Gemini 3.1 Flash-Lite and GPT-5.5 Instant; plan for SDK, billing, or endpoint changes.
  • GPT-5.5 Instant is $28.50/1M tokens higher on cheapest tracked output pricing, so quality gains need to justify the spend.
GPT-5.5 Instant -> Gemini 3.1 Flash-Lite
  • No overlapping tracked provider route is sourced for GPT-5.5 Instant and Gemini 3.1 Flash-Lite; plan for SDK, billing, or endpoint changes.
  • Gemini 3.1 Flash-Lite is $28.50/1M tokens lower on cheapest tracked output pricing before cache, batch, or negotiated discounts.

Specs

Specification
Released2026-05-072026-05-05
Context window1.05m400k
Parameters——
ArchitectureDecoder OnlyDecoder Only
LicenseProprietaryProprietary
OpennessProprietaryProprietary
WeightsNot releasedNot released
CodeUnknownUnknown
Commercial useCommercial use: conditionalCommercial use: conditional
Knowledge cutoff2025-012025-08

Pricing and availability

Pricing attributeGemini 3.1 Flash-LiteGPT-5.5 Instant
Input price$0.25/1M tokens$5/1M tokens
Output price$1.50/1M tokens$30/1M tokens
Providers
Google AI StudioOpenRouterVercel AI Gateway
OpenAI API

Capabilities

CapabilityGemini 3.1 Flash-LiteGPT-5.5 Instant
VisionYesYes
MultimodalYesYes
ReasoningNoNo
JSON / Tool useYesYes
Structured outputsYesYes
Code executionYesYes
IDE integrationNoNo
Computer useNoNo
Parallel agentsNoNo

Benchmarks

BenchmarkGemini 3.1 Flash-LiteGPT-5.5 Instant
MMMU Pro76.876.0

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Model pages
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Last reviewed: 2026-06-29. Data sourced from public model cards and provider documentation.