How many tokens does a 13-point story take to build with AI?
A 13-point user story typically takes about 2,940,000 tokens to build with an AI coding agent (roughly 1,260,000–6,300,000 depending on complexity), about $8.40 at today's GPT-4o prices ($3.60–$18.00). This is the build-time (developer) cost, not the cost of running the finished feature.
A 13-point story is the top of most Fibonacci scales — a size that usually means 'break this down.' If built as one push, an AI agent accumulates millions of input tokens across long, iterative sessions, so the cost is best estimated by splitting it into smaller stories.
Token & cost ranges
Cost uses GPT-4o at current prices. Verified 29 July 2026.
| Scenario | Input tokens | Output tokens | Total tokens | Est. cost |
|---|---|---|---|---|
| Low (simple) | 1,200,000 | 60,000 | 1,260,000 | $3.60 |
| Typical | 2,800,000 | 140,000 | 2,940,000 | $8.40 |
| High (complex) | 6,000,000 | 300,000 | 6,300,000 | $18.00 |
Typical cost by model
The same typical token estimate priced across a few common coding models.
| Model | Typical cost | Range (low–high) |
|---|---|---|
| GPT-4o | $8.40 | $3.60 – $18.00 |
| GPT-4o mini | $0.5040 | $0.2160 – $1.08 |
| Claude Sonnet 4.6 | $10.50 | $4.50 – $22.50 |
| Gemini 2.0 Flash | $0.3360 | $0.1440 – $0.7200 |
How we estimate this
A 13-point story is very large and usually a signal to split. Expect many turns across many files, repeated test/fix cycles, and long context. Input tokens dominate because an agent re-sends file context on every turn; output is the generated code, diffs and tests. Treat these as planning ranges, not a quote — your real usage depends on codebase size, model, prompt caching and how many iterations it takes.
Examples of this size
- A whole feature area with several screens
- A migration plus the code that depends on it
- A vertical slice of a new product capability
Estimate it with your own model
Plug in your model, complexity and prompt-caching to get a tailored range.
Frequently asked questions
How many tokens does a 13-point user story take to build with AI?+
A 13-point user story typically takes about 2,940,000 tokens to build with an AI coding agent (roughly 1,260,000–6,300,000 depending on complexity), about $8.40 at today's GPT-4o prices ($3.60–$18.00). This is the build-time (developer) cost, not the cost of running the finished feature.
Is this the cost to build it or to run it?+
This is the build-time (developer) cost — the tokens an AI coding agent burns while implementing the work. Running the finished feature is a separate, usually much smaller per-request cost.
Why is the range so wide?+
A 13-point story is very large and usually a signal to split. Expect many turns across many files, repeated test/fix cycles, and long context. Input tokens dominate because an agent re-sends file context on every turn; output is the generated code, diffs and tests. Treat these as planning ranges, not a quote — your real usage depends on codebase size, model, prompt caching and how many iterations it takes.
How can I lower the cost?+
Split large work into smaller pieces, enable prompt caching so re-sent context is billed at the cheaper cache-read rate, and use a cheaper model for routine steps. Try your own model in the Cost to build X estimator.