OpenAI vs Anthropic vs Google: Which Is Cheapest for Your Use Case?

March 18, 2026

We ran a quick experiment last quarter. Same workload — 100k requests per day, mixed input/output — across OpenAI, Anthropic, and Google. The cheapest provider for our use case was $2,400/month. The most expensive was $4,100. Same workload. Different provider. OpenAI vs Anthropic vs Google cost: the ranking flipped when we changed the input/output ratio. There's no single cheapest provider — it depends on your mix. Which AI provider is cheapest? Run the numbers for your workload.

OpenAI vs Claude vs Gemini pricing: input-heavy vs output-heavy

Our document analysis is input-heavy: long context, short outputs. Input pricing mattered most. Gemini 2.0 Flash won. Our email drafting feature is output-heavy: short prompt, long replies. Output pricing dominated. Different ranking. The cheapest provider for one workload can be the most expensive for another. OpenAI vs Anthropic vs Google pricing: you need to compare for your specific input/output ratio. We learned that the hard way.

How to compare OpenAI vs Anthropic vs Google cost

Plug your typical input tokens, output tokens, and request volume into a comparison tool. See the monthly cost for each model. Cheapest AI provider for your use case might be different from ours. Our OpenAI vs Anthropic vs Google comparison does this. Once you know which provider and model fit, you still need cost by customer — that's what PerUnit provides.

What we found when we compared

For our input-heavy document work, we switched to Gemini. OpenAI vs Anthropic vs Google cost: Gemini won for that workload. For our output-heavy email drafting, Claude was competitive. For our mixed chat workload, we stayed on GPT-4.1. Which AI provider is cheapest — there's no single answer. You need to run the numbers for your workload. OpenAI vs Claude vs Gemini pricing shifts by model and by input/output ratio. We saved $800/month by matching provider to each feature. The OpenAI vs Anthropic vs Google comparison we ran paid for itself in the first week.