Billing options control when and how often your customers are charged. Milo Subscriptions builds every subscription on a small set of primitives: billing period, billing interval, length, trial, sign-up fee, and sync. This page explains how they work together and what combinations are possible.
The core concepts
Billing period
The unit of time between renewals. One of:
- Day
- Week
- Month
- Year
Billing interval
The number of billing periods between each renewal. Combined with the billing period, this defines the cadence.
| Period | Interval | Result |
|---|---|---|
| Day | 1 | Daily |
| Week | 1 | Weekly |
| Week | 2 | Every 2 weeks |
| Month | 1 | Monthly |
| Month | 3 | Quarterly |
| Month | 6 | Twice a year |
| Year | 1 | Annually |
| Year | 2 | Every 2 years |
Intervals can go up to 6 for days/weeks/months and 5 for years. For cadences outside these ranges, combine the primitives differently (for example, 24 months rather than 2 years).
Length
How many billing periods the subscription runs before it completes automatically. The default is Never expire, which creates an open-ended subscription that continues until the customer cancels or a payment fails.
Free trial
A period at the start of the subscription during which no recurring charge is taken. The first renewal is scheduled at the end of the trial. Trials are independent of the billing period: you can offer a 30-day trial on a monthly subscription, or a 3-month trial on an annual subscription.
Sign-up fee
A one-time amount charged at checkout, in addition to the first renewal or alongside a free trial. Use sign-up fees for setup charges, onboarding, or discounted first periods.
Fixed expiry date
A specific calendar date on which the subscription ends, regardless of when it started. Useful for annual memberships or access that must end on a known date (end of season, end of fiscal year).
Synchronized renewals
Align all renewals to a fixed day. For example, every customer on a monthly plan renews on the 1st of the month. See Synchronized renewals.
How the first payment is calculated
The customer’s first payment is the sum of:
- The sign-up fee, if any.
- The subscription price for the first period, unless a free trial is active.
- A prorated amount, if synchronized renewals are enabled and proration is turned on.
Taxes and shipping are added on top as configured in WooCommerce.
How renewals are scheduled
After checkout, Milo Subscriptions schedules the next payment date based on:
- The start date of the subscription (or the end of the trial, if a trial is active).
- The billing period and billing interval.
Each successful renewal pushes the next payment date forward by one billing cycle. Failed renewals trigger retries according to your dunning settings.
Length, fixed expiry, and minimum periods
These three fields define when the subscription stops, and they interact:
- Length ends the subscription after a number of successful renewals.
- Fixed expiry ends it on a specific calendar date.
- Minimum periods prevents the customer from cancelling before a minimum number of payments.
If both Length and Fixed expiry are set, whichever comes first ends the subscription. Minimum periods only affects cancellation, not end dates.
Prorated payments
Proration applies when:
- A customer switches between variations mid-cycle.
- Synchronized renewals require aligning a new subscription to a fixed renewal day.
You control proration behavior per product (for switches) and globally (for sync) under Milo Subscriptions → Settings.
Example scenarios
Monthly SaaS, never expires, no trial
- Billing period: Month
- Billing interval: 1
- Length: Never
- First payment: subscription price. Renewals monthly until cancelled.
Annual membership with 30-day free trial
- Billing period: Year
- Billing interval: 1
- Free trial: 30 days
- First payment: $0 at checkout. First renewal 30 days later, then yearly.
Prepaid 12-month course
- Billing period: Month
- Billing interval: 1
- Length: 12
- Charged monthly for 12 months, then the subscription completes automatically.
Seasonal subscription with fixed expiry
- Billing period: Month
- Billing interval: 1
- Fixed expiry: 2026-12-31
- Charged monthly until 2026-12-31, then the subscription ends.
Changing billing options after purchase
Billing options are set at purchase time and do not automatically update existing subscriptions when you change the product. To change an existing customer’s billing cadence:
- Let them switch to another variation.
- Edit the subscription directly from Milo Subscriptions → Subscriptions (admin only).
Next steps
- Renewals: what happens when a renewal is due, and how retries work.
- Switching: change plans mid-subscription.
- Synchronized renewals: align renewals to a fixed day.