GPT-5 Cost Calculator
Estimate cost for GPT-5 — OpenAI's flagship reasoning model. Input $5/1M, output $25/1M (as of 2026). Larger context window than GPT-4o.
GPT-5 pricing (per 1M tokens)
OpenAI's flagship — 256K context, top-tier reasoning. Output is 5x more expensive than input.
| Model | Input | Output | Context |
|---|---|---|---|
| GPT-5 | $5.00 | $25.00 | 256K |
What you'll use this for
Forecasting AI spend is the difference between a sustainable feature and an unexpected invoice. Pre-flight every prompt.
Budget planning
Forecast monthly and annual costs based on expected call volume and prompt size.
Model selection
Compare model size variants side-by-side to pick the right cost/quality tradeoff.
Cost optimization
See how prompt caching, shorter outputs, and smaller models slash bills.
Pricing transparency
All rates visible up front — no surprises after the invoice arrives.
How to estimate GPT costs
Paste your prompt
Drop a representative prompt into the left editor. Tokens are estimated at ~4 chars/token.
Set expected output tokens
How long do you expect the response to be? Default 500 covers a paragraph or two.
Set calls per day
How often does this prompt run? 100 = trial-scale, 10000+ = production-scale.
Read the forecast
Per-call, per-day, per-month, per-year totals update live as you tweak inputs.
Frequently asked questions
We use ~4 chars/token, accurate to about ±20%. For exact counts use the model-specific token counter such as the OpenAI token counter.
OpenAI's public pricing pages as of 2026. Subject to change — always confirm at openai.com/pricing before signing contracts.
Yes. Completely free, no signup, runs entirely in your browser.
Toggle "Cached input" for a 90% input discount — this is approximate and varies by provider. OpenAI's prompt caching kicks in for repeated prefixes ≥ 1024 tokens.
Provider tokenizers can differ slightly from our estimate; system prompts and tool definitions also count toward input; rates change over time. Treat this as a planning tool, not a billing replica.
About GPT-5 API pricing
GPT-5 is OpenAI's most capable model: 256K context, deep reasoning, multimodal. At $5/1M input and $25/1M output it commands a premium — but for complex agents, long-document synthesis, and hard reasoning it earns it.
When GPT-5 is worth the spend
- Multi-step agentic workflows with tool use.
- Long-document analysis up to 256K tokens.
- Hard reasoning: math, code synthesis, planning.
- Cases where one good call beats five mediocre ones.
How to control spend
- Bound output tokens — output is 5x input.
- Cache system prompts (~90% discount).
- Route simpler subtasks to GPT-4o or 4o mini.
- Use Batch API where realtime isn't required (~50% off).