---
title: Flat fee
description: Charge one fixed amount per billing period, no matter the quantity or usage.
domain: pricing
status: shipped
visibility: public
last_verified: 2026-07-11
order: 10
---
Flat fee is the simplest model. The customer pays one fixed amount every billing period. Quantity does not change the price.

Use it for plans like "Pro at $99 per month" where everyone on the plan pays the same.

## Worked example

You sell a Pro plan at $99 per month.

| What happens | Amount |
|---|---|
| Customer subscribes on May 1 | $99.00 invoiced for May 1 to May 31 |
| Renewal on June 1 | $99.00 invoiced for June 1 to June 30 |

The quantity on the subscription item is always 1 for a flat fee price. Adding seats or usage does not change the charge. If you need the price to grow with a number, use per unit, tiered, volume, or stairstep pricing instead.

## Settings

| Setting | What it does |
|---|---|
| Amount | The fixed charge per period, in the price's currency. |
| Billing period | How often it charges: day, week, month, or year, times a count. "Every 3 months" is a quarterly flat fee. |
| Billing timing | In advance (default) charges at the start of the period. In arrears charges at the end. |
| Trial days | Free days before the first charge. |

## Edge cases

- **Mid-period changes.** If the customer switches to another price mid-period, proration rules decide the credit and the new charge. See the proration page.
- **Minimums and maximums do not apply.** A flat fee is already a fixed amount, so per-line guardrails have nothing to clamp.

## In the API

Create a price with `pricing_model: "flat"` and the amount in minor units:

```json
{
  "pricing_model": "flat",
  "pricing_config": { "unit_amount": 9900 },
  "currency": "USD",
  "billing_period_unit": "month",
  "billing_period_count": 1
}
```