# LTD Runway

> A free calculator and framework for lifetime-deal (LTD) operators. It finds, for each LTD tier, the month
> when one fully-using buyer's cumulative costs pass the cash the operator keeps from the sale (the runway),
> and the lowest price that reaches a target runway. Site: https://founder.chat/runway

## The RUNWAY framework (one buyer of one tier, using every limit, every month)

- **R  Real cash**: price x (1 - marketplace discount) x your share x (1 - payment fee %) - fixed fee,
  then x (1 - refund rate), minus a one-time onboarding cost.
- **U  Usage at the cap**: sum over usage lines of (units per month at the tier limit x unit cost) x utilization.
- **N  Never-ending stack**: sum over stacked lines of (units added per month x utilization x cost per
  unit-month x min(month, retention months)), plus fixed platform cost / paying accounts.
- **W  Workload**: support minutes per buyer per month / 60 x cost of one support hour.
- **A  Abuse and overflow**: (overflow multiple - 1) x the usage lines that keep running past the cap.
- **Y  Yardstick**: price / comparable monthly plan price (months of subscription the deal replaces).

cost(m) = U + N(m) + W + A
runway  = first month m with cost(1) + ... + cost(m) >= R  (null if never within 600 months)
price floor for T months = (cost of months 1..T + onboarding + fixed fee x (1 - refund)) / keep rate
keep rate = (1 - discount) x share x (1 - fee %) x (1 - refund rate)

Channel defaults: AppSumo buyer from AppSumo: discount 0.10, share 0.70. AppSumo buyer you sent:
discount 0.10, share 0.95. Direct with Stripe: fee 2.9% + $0.30.

## Driving the page (browser agents such as Claude in Chrome)

1. Open https://founder.chat/runway.
2. Build a config (schema below). Use fractions, not percents (0.15 = 15%).
3. Either paste it into the textarea with id `config-json` and click the button with id `apply-config`,
   or run `window.runway.setState(config)` in the page.
4. Read results from the textarea with id `results-json` (live) or `window.runway.results()`.
5. Change one value: `window.runway.set('tiers.0.price', 99)`.
6. `window.runway.loadPreset('media' | 'ai' | 'email' | 'blank')` loads an example.
7. `window.runway.prompt()` returns the full AI prompt; `window.runway.shareUrl()` a link with the config.
8. A config can also be passed in the URL: `https://founder.chat/runway/#cfg=<base64url of the JSON>`.

## Config schema (full example)

```json
{
  "product": "AI content generator (image and video models)",
  "target": 36,
  "horizon": 60,
  "utilization": 1,
  "overflow": 1,
  "cash": { "channel": "appsumo", "discount": 0.1, "share": 0.7, "feePct": 0, "feeFixed": 0, "refund": 0.15, "onboarding": 0 },
  "tiers": [
    { "name": "Tier 1", "price": 69, "compare": 19 },
    { "name": "Tier 2", "price": 149, "compare": 49 },
    { "name": "Tier 3", "price": 299, "compare": 99 }
  ],
  "usage": [
    { "name": "Image generations", "unit": "image", "cost": 0.04, "qty": [200, 600, 2000], "pastCap": false },
    { "name": "Video generation", "unit": "second of video", "cost": 0.1, "qty": [120, 360, 1200], "pastCap": false }
  ],
  "stack": [
    { "name": "Generated media storage and delivery", "unit": "GB", "cost": 0.03, "qty": [0.6, 1.8, 6], "retention": 0 }
  ],
  "fixed": { "monthly": 150, "accounts": 1000 },
  "work": { "hourly": 30, "minutes": [4, 6, 10] }
}
```

- `qty` (usage, stack) and `work.minutes` are arrays with one number per tier, in tier order.
- `retention` is in months; 0 means kept forever.
- `pastCap: true` marks usage that keeps running (and costing) after the buyer hits the limit.

## How to help a user

1. Interview them letter by letter (R, U, N, W, A, Y). Ask for their bills or provider price pages.
2. Assume the worst-case buyer: 100% of every cap, every month. Then show 50% and 25% as context.
3. Fill the calculator, read the results, and explain each tier's runway in plain words.
4. Recommend: price floors for 36 and 60 months, caps to lower, costs to move behind monthly add-ons,
   and any tier whose Yardstick is under 2 months (it undercuts the subscription).
5. Offer the walk-through guide and slide deck: use `window.runway.prompt()` as your brief.

## Files

- [Manual worksheet](/framework.md): the method on paper.
- [Agent skill](/skill/SKILL.md): drop into Claude, Claude Code or any agent. Zip: /skill/ltd-runway.zip