TokenAtlasWhat OpenAI actually costs
OpenAI is billed per token. As of 2026, OpenAI charges approximately $2.50 per million input tokens and $10.00 per million output tokens. That sounds tiny — until you multiply by a million calls a month. The TokenAtlas OpenAI calculator turns those numbers into a real monthly bill so finance and engineering see the same picture.
How to estimate OpenAI spend
The OpenAI bill is rarely one model. A 1,000-token prompt with a 500-token reply is $0.0075 on GPT-4o, but roughly $0.0004 on GPT-4o mini — an 18x spread for the same request. Enter your average input tokens, average output tokens and calls per day once, and TokenAtlas projects the OpenAI monthly bill per model so you can see which tier your traffic actually belongs on before you standardise on one.
Context window: 128K tokens
OpenAI ships with a 128K tokens context window. Longer prompts mean more input tokens on every call. If you're running RAG with large retrieved chunks, this calculator shows you exactly how much that retrieval is costing per request.
Best fit: general-purpose reasoning and tool use
OpenAI is strongest at general-purpose reasoning and tool use. If your workload doesn't match that profile, swap it for a cheaper or faster model — the calculator's compare view runs the same scenario across every major provider.
What the calculator outputs
Cost per call, daily, monthly and annual OpenAI spend, and cost per active user at your volume. Because OpenAI prices output at roughly 4x input across the GPT-4 family, the breakdown separates prompt cost from completion cost so you can see which half of the bill to attack. The compare view re-runs the same scenario on GPT-4o mini, Claude and Gemini, so the routing decision — premium model for hard requests, cheap model for the long tail — is made on modelled dollars rather than intuition.
Frequently asked questions
- Is the OpenAI pricing data up to date?
- Yes — TokenAtlas tracks OpenAI's pricing page and ships updates within 24 hours of any change.
- Does this include image, audio or fine-tuned model pricing?
- Text in/out is covered for OpenAI. Multimodal and fine-tuned variants are tracked separately.
- Can I save scenarios?
- Free accounts can save up to 5 scenarios. Pro and Team plans get unlimited saved calculations and exports.
- How accurate are the estimates?
- Within ~3% of your real bill assuming consistent token counts.