LLM Reference

Gemini 2.5 Pro vs Phi 3.5 Mini Instruct

Gemini 2.5 Pro (2025) and Phi 3.5 Mini Instruct (2024) are frontier reasoning models from Google DeepMind and Microsoft Research. Gemini 2.5 Pro ships a 1m-token context window, while Phi 3.5 Mini Instruct ships a 128k-token context window. This comparison covers specs, pricing, API access, capabilities, benchmarks, input and output token costs, and production fit for coding and agent workloads.

Gemini 2.5 Pro fits 8x more tokens; pick it for long-context work and Phi 3.5 Mini Instruct for tighter calls.

Decision scorecard

Local evidence first
SignalGemini 2.5 ProPhi 3.5 Mini Instruct
Best forreasoning-heavy apps, multimodal apps, and tool-calling agentsprovider-routed production
Decision fitCoding, RAG, and AgentsLong context
Context window1m128k
Cheapest output$10/1M tokens$0.90/1M tokens
Provider routes4 tracked2 tracked
Shared benchmarks0 shared0 shared

Decision tradeoffs

Choose Gemini 2.5 Pro when...
  • Gemini 2.5 Pro has the larger context window for long prompts, retrieval packs, or transcript analysis.
  • Gemini 2.5 Pro has broader tracked provider coverage for fallback and route flexibility.
  • Gemini 2.5 Pro uniquely exposes Vision, Multimodal, and Reasoning in local model data.
  • Local decision data tags Gemini 2.5 Pro for Coding, RAG, and Agents.
Choose Phi 3.5 Mini Instruct when...
  • Phi 3.5 Mini Instruct has the lower cheapest tracked output price at $0.90/1M tokens.
  • Local decision data tags Phi 3.5 Mini Instruct for Long context.

Monthly cost at traffic

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

Lower estimate Phi 3.5 Mini Instruct

Gemini 2.5 Pro

$3,500

Cheapest tracked route/tier: Google AI Studio <=200K tokens

Phi 3.5 Mini Instruct

$945

Cheapest tracked route/tier: Fireworks AI

Estimated monthly gap: $2,555. Batch, cache, alternate speed tiers, and negotiated pricing are excluded from this local estimate.

Switch friction

Gemini 2.5 Pro -> Phi 3.5 Mini Instruct
  • No overlapping tracked provider route is sourced for Gemini 2.5 Pro and Phi 3.5 Mini Instruct; plan for SDK, billing, or endpoint changes.
  • Phi 3.5 Mini Instruct is $9.10/1M tokens lower on cheapest tracked output pricing before cache, batch, or negotiated discounts.
  • Check replacement coverage for Vision, Multimodal, and Reasoning before moving production traffic.
Phi 3.5 Mini Instruct -> Gemini 2.5 Pro
  • No overlapping tracked provider route is sourced for Phi 3.5 Mini Instruct and Gemini 2.5 Pro; plan for SDK, billing, or endpoint changes.
  • Gemini 2.5 Pro is $9.10/1M tokens higher on cheapest tracked output pricing, so quality gains need to justify the spend.
  • Gemini 2.5 Pro adds Vision, Multimodal, and Reasoning in local capability data.

Specs

Specification
Released2025-06-172024-08-20
Context window1m128k
Parameters3.8B
ArchitectureDecoder OnlyDecoder Only
LicenseProprietaryMITOSI-approved
OpennessProprietaryOpen source
WeightsNot releasedUnknown
CodeUnknownUnknown
Commercial useCommercial use: conditionalCommercial use: permitted
Knowledge cutoff2025-012023-10

Pricing and availability

Pricing attributeGemini 2.5 ProPhi 3.5 Mini Instruct
Input price
<=200K tokens
$1.25/1M tokens
Standard Gemini 2.5 Pro pricing for prompts up to 200K tokens.
>200K tokens
$2.50/1M tokens
Higher Gemini 2.5 Pro tier for prompts above 200K tokens.
$0.90/1M tokens
Output price
<=200K tokens
$10/1M tokens
Standard Gemini 2.5 Pro pricing for prompts up to 200K tokens.
>200K tokens
$15/1M tokens
Higher Gemini 2.5 Pro tier for prompts above 200K tokens.
$0.90/1M tokens
Providers

Capabilities

CapabilityGemini 2.5 ProPhi 3.5 Mini Instruct
VisionYesNo
MultimodalYesNo
ReasoningYesNo
JSON / Tool useYesNo
Structured outputsYesNo
Code executionYesNo
IDE integrationNoNo
Computer useNoNo
Parallel agentsNoNo

Benchmarks

No shared benchmark scores are currently available for this pair.

Continue comparing

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