Prorations

The most complex aspect of changing existing subscriptions are prorations, where the customer is charged a percentage of a subscription’s cost to reflect partial use. This page explains how prorations work with subscriptions and how to manage prorations for your customers.

How prorations work

For example, upgrading or downgrading a subscription can result in prorated charges. If a customer upgrades from a 10 USD per month plan to a 20 USD option, they’re charged pro-rata amounts for the time spent on each option. Assuming the change occurred halfway through the billing period, the customer is billed an additional 5 USD: -5 USD for unused time on the initial price, and 10 USD for the remaining time on the new price.

Proration ensures that customers are billed accurately, but a proration can result in different payment amounts than you may expect. Negative prorations aren’t automatically refunded and positive prorations aren’t immediately billed, although you can do both manually.

You can preview a proration to view the amount before applying the changes.

Prorations and discounts

Any adjustments from discounts are reflected in the proration invoice item’s amount. Additional discounts at the invoice item level or invoice line item level don’t apply to prorations because they have discountable=false.

This behaviour is different from non-prorations, which show discount adjustments in discount_amounts.

What triggers prorations

By default, the following scenarios result in a proration:

• Changing to a price with a different base cost
• Changing to a price with a different billing interval
• Adding a trial period to an active subscription
• Changing the quantity
• Licensed (per-seat) subscriptions (because they’re billed at the start of each billing period)

Manually creating your own prorations

To calculate your own prorations outside of Stripe and add them to the subscription, pass add_invoice_items with negative unit_amounts (equal to the calculated proration amount) to these endpoints:

• CreateSubscription
• UpdateSubscription
• CreateSubscriptionSchedule
• UpdateSubscriptionSchedule

When prorations are applied

Prorations only apply to charges that occur ahead of the billing cycle. Usage-based billing isn’t subject to proration.

The prorated amount is calculated as soon as the API updates the subscription. The current billing period’s start and end times are used to calculate the cost of the subscription before and after the change.

Taxes and prorations

For information about how taxes work with prorations, see Collect taxes for recurring payments.

Preview a proration

You can retrieve an upcoming invoice to preview changes to a subscription. This API call doesn’t modify the subscription, it returns the upcoming invoice based only on the parameters that you pass. Changing the price or quantity both result in a proration. This example changes the price and sets a date for the proration.

# Set your secret key. Remember to switch to your live secret key in production.
# See your keys here: https://dashboard.stripe.com/apikeys
Stripe.api_key = 
'sk_test_4eC39HqLyjWDarjtT1zdp7dc'

# Set proration date to this moment:
proration_date = Time.now.to_i

subscription = Stripe::Subscription.retrieve('sub_49ty4767H20z6a')

# See what the next invoice would look like with a price switch
# and proration set:
items = [{
  id: subscription.items.data[0].id,
  price: 'price_CBb6IXqvTLXp3f', # Switch to new price
}]

invoice = Stripe::Invoice.upcoming({
  customer: 'cus_4fdAW5ftNQow1a',
  subscription: 'sub_49ty4767H20z6a',
  subscription_items: items,
  subscription_proration_date: proration_date,
})

You can expand the example response below to see:

• The credit for unused time at the previous price on lines 36-38.
• The cost for time spent at the new price on lines 107-109.
• The new subtotal and total for the invoice on lines 276-279.

{
  "account_country": "US",
  "account_name": "Test account",
  "amount_due": 3627,
  "amount_paid": 0,
  "amount_remaining": 3627,
  "application_fee_amount": null,
  "attempt_count": 0,
  "attempted": false,
  "billing_reason": "upcoming",

Use this information to confirm the changes with the customer before modifying the subscription. Because Stripe calculates pro-rata values to the second, pro-rata amounts may change between the time they’re previewed and the time the update is made. To avoid this, pass in a subscription_proration_date to the invoice when you preview a change. When you update the subscription, pass the same date using the proration_date parameter on a subscription so that the proration is calculated at the same time.

# Set your secret key. Remember to switch to your live secret key in production.
# See your keys here: https://dashboard.stripe.com/apikeys
Stripe.api_key = 
'sk_test_4eC39HqLyjWDarjtT1zdp7dc'

subscription = Stripe::Subscription.update(
  'sub_49ty4767H20z6a',
  {
    items: [
      {
        id: subscription.items.data[0].id,
        price: 'price_CBb6IXqvTLXp3f',
      },
    ],
    proration_date: proration_date,
  }
)

Disable prorations

Prorating is controlled by the proration_behavior parameter and defaults to create_prorations.

To disable prorations on a per-request basis, set the proration_behavior parameter to none. No parameter turns off all future prorations for a Subscription. To disable prorations indefinitely, set proration_behavior to none for every request that generates prorations:

curl https://api.stripe.com/v1/subscriptions/sub_49ty4767H20z6a \
  -u 
sk_test_4eC39HqLyjWDarjtT1zdp7dc
: \
  -d "items[0][id]"="si_1AkFf6LlRB0eXbMtRFjYiJ0J" \
  -d "items[0][price]"="price_CBb6IXqvTLXp3f" \
  -d "proration_behavior"="none"

When prorations are disabled, customers are billed the full amount at the new price when the next invoice is generated.