GPT-5 vs Gemini 3.5 Flash
OpenAI's popular premium model vs Google's fast mid-tier model. Compare pricing, context windows, and find the best value for your workload.
Pricing data verified: Jun 20, 2026
| Specification | GPT-5 (OpenAI) | Gemini 3.5 Flash (Google) |
|---|---|---|
| Input Price (per 1M tokens) | $1.25 | $1.50 |
| Output Price (per 1M tokens) | $10.00 | $9.00 |
| Context Window | 1M tokens | 1M tokens |
| Tier | Premium | Mid |
| Provider | OpenAI | |
| Best For | Input-heavy tasks (17% cheaper input) | Output-heavy tasks (10% cheaper output) |
Calculate Your Exact Costs
Two models with similar pricing — the winner depends on your input/output ratio.
Which Model for Which Use Case?
SaaS Chatbot
High-volume customer-facing chat with short responses. GPT-5's cheaper input ($1.25 vs $1.50) makes it better for chatbot workloads with many input tokens.
Content Generation at Scale
Blog posts, marketing copy, long-form content. Gemini 3.5 Flash's cheaper output ($9 vs $10) makes it better for output-heavy content tasks.
Code Assistant
Code generation, review, and refactoring. Both models handle code well. GPT-5's cheaper input gives it a slight edge for code-heavy workloads.
Data Analysis
Processing large datasets, generating insights, and creating reports. Similar pricing — choose based on your input/output ratio.
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Frequently Asked Questions
How much cheaper is Gemini 3.5 Flash than GPT-5?
Gemini 3.5 Flash costs $1.50/$9 per 1M tokens while GPT-5 costs $1.25/$10 per 1M tokens. GPT-5 is 17% cheaper on input but Gemini 3.5 Flash is 10% cheaper on output. For input-heavy workloads, GPT-5 is cheaper. For output-heavy workloads, Gemini 3.5 Flash wins.
Which has a larger context window?
Both models have a 1M token context window, making them equally capable for processing long documents and conversations. Neither has an advantage in context length.
When should I choose GPT-5 over Gemini 3.5 Flash?
Choose GPT-5 when you need: (1) Maximum OpenAI quality for complex tasks, (2) Input-heavy workloads where GPT-5's $1.25 input beats Gemini's $1.50, (3) Enterprise reliability from OpenAI's infrastructure. Choose Gemini 3.5 Flash for output-heavy workloads where it's 10% cheaper.
Can I mix GPT-5 and Gemini 3.5 Flash to optimize costs?
Yes. Route input-heavy tasks to GPT-5 ($1.25 input) and output-heavy tasks to Gemini 3.5 Flash ($9 output). This mixed strategy can save 10-20% while maintaining quality across both models.