---
title: Anniversary and calendar billing
description: Bill each customer on their own start day, or align everyone to one day of the month.
domain: subscription
status: shipped
visibility: public
last_verified: 2026-07-12
order: 20
---
There are two ways to decide which day a subscription bills on. Anniversary billing uses each customer's own start day. Calendar billing lines everyone up on one day of the month. Calendar billing has a master switch for your whole organization; when it is off, everything is anniversary.

## Anniversary billing (the default)

Each subscription anchors to the day it started. A monthly plan that begins on the 8th renews on the 8th of every month. A customer who signs up on the 22nd bills on the 22nd. Everyone is on their own cycle.

This is the simplest model and it needs no setup. Every customer's bill lands a clean month (or period) after the last one.

## Calendar billing

Calendar billing aligns monthly subscriptions to a single day of the month, so all your invoices go out together. You pick the day, from 1 to 28, so it exists in every month.

Because a customer rarely signs up exactly on that day, their first period is shorter than a full month: it runs from their start date to the first aligned billing day. That short first period is called the stub.

```viz calendar-stub
```

## How the short first period is billed

You choose how the stub is charged:

- **Prorate (the default):** charge only for the part of the month the customer actually gets. Fairest for the customer.
- **Full:** charge a full period for the stub, as if it were a normal month.
- **Free:** charge nothing for the stub. Billing starts clean on the first aligned day.

After the stub, every period is a normal full month landing on your chosen day.

## When a subscription drifts off its day later

The stub is not only a first-period thing. A calendar-billed subscription can drift off its aligned day after it has been running, and when it does, the next renewal snaps it back with another short period. Two things cause the drift:

- **A pause and resume.** Time spent paused shifts the billing dates forward, so the subscription resumes off its aligned day. See [pausing and resuming](/guide/subscriptions/pausing-and-resuming).
- **A billing-day change.** Moving a running subscription to a different aligned day (below) leaves a short transition period between the old day and the new one.

```viz calendar-realignment
```

The short realignment period is billed by the **same stub policy** you set for signups: prorate, full, or free. There is no separate setting for it, and prorate is the default, so by default the customer pays only for the days in that short period.

> [!NOTE]
> The stub policy you choose applies to every short period, not just the first one. Whenever a calendar-billed subscription realigns to its day, that short period follows the same prorate, full, or free rule as a signup stub.

## Changing the billing day later

You can move a running subscription to a different aligned day from its detail page, or with `POST /v1/subscriptions/{id}/billing-day`. You see a preview of the dates and money before you confirm. There are two ways it can take effect:

- **At the next renewal.** The day changes at the next renewal. The short transition period between the old day and the new one is billed by your stub policy, the same as any realignment.
- **Immediately.** The current period is re-cut to the new day now. The difference settles on the next invoice as a prorated credit if the period got shorter, or a prorated charge if it got longer, at the daily rate the customer already pays.

See the [API reference](/reference) for the billing-day endpoint.

## Turning calendar billing on

Calendar billing is off by default, so every organization starts on anniversary billing. Turning it on, choosing the aligned day, and picking how the short first period is billed (prorate is the default) are all organization settings.

You change these for your whole organization under Settings, on the billing behavior preferences ([open settings](https://app.yrecurring.com/settings/preferences) if you are signed in). Turning calendar billing on changes how new monthly subscriptions are anchored; it does not move existing subscriptions unless you re-align them.

## Which day wins

A billing day can be set at more than one level. The most specific setting wins:

1. A day set on the subscription itself.
2. A day set on the customer.
3. Your organization's calendar billing day.
4. If none of those apply, anniversary billing.

## Edge cases

- **Calendar billing is monthly only.** Aligning a yearly or weekly plan to a day of the month does not apply; those keep their own cycle.
- **Days run 1 to 28.** Not every month has a 29th, 30th, or 31st, so the aligned day stays in the range that exists everywhere.
- **A free trial aligns its first paid period, not the trial.** The trial runs its full length; the stub and its billing choice apply to the first paid period after the trial ends.