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Calculated fields are read-only custom fields whose value is computed from a Liquid formula. A single formula can pull from both Supercycle custom fields and Shopify metafields on the same record, so you can derive values across any custom data you’re already capturing. For example, you can multiply a daily rate by a duration to get a total, or set a flag based on a metafield. Calculated fields are available on the same resources as custom fields (items, cycles, and consignors) and appear alongside regular custom fields in the Custom fields section on the record. Their value updates on demand via a Recalculate button on each field.

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Create a calculated field

1

Open custom data settings

In Shopify Admin, head to Supercycle > Settings > Custom data and choose Items, Cycles, or Consignors.
2

Add a calculated definition

Click Add definition on the calculated fields card.
3

Configure the field

Set up your calculated field:
  • Name: Display name shown on the record (e.g., “Total rental cost”).
  • Key: Auto-generated identifier based on the name (can be manually edited).
  • Result type: The type of value the formula produces. Choose from single line text, multi line text, money, integer, boolean, date, or date and time.
  • Formula: A Liquid expression that computes the value.
4

Save definition

Click Save to create the calculated field.
The result type cannot be changed after creation. Choose the appropriate type when creating the definition.

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Writing formulas

Formulas use Liquid, the same templating language Shopify themes and notifications use. A formula is any Liquid expression that renders to a value matching the field’s result type. The form lists the available variables as clickable pills. Click one to insert it into your formula.

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General rules

  • Formulas are evaluated in strict mode. Referencing an undefined variable causes the formula to fail.
  • Only scalar custom fields are referenceable. Reference fields (customer, cycle, item, return), color, URL, and JSON custom fields are not available in formulas.
  • A calculated field cannot reference another calculated field.
  • Money values are always in cents (integer). For example, $15.00 is 1500. A money-typed formula must also produce cents.
Money fields are represented in cents inside formulas. Multiply and divide accordingly when combining money with other numbers, and remember that the result of a money-typed formula also has to be in cents.
For example, to compute a 10% discount off a daily rate stored as money: 
{{ fields.daily_rate | times: 0.9 }}
To convert an integer number of dollars into a money result, multiply by 100: 
{{ fields.dollars | times: 100 }}

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Liquid basics

Liquid has two kinds of markup:
  • Output: {{ ... }} renders a value. Everything a formula produces has to end up inside output tags.
  • Tags: {% ... %} control logic and don’t render anything themselves (e.g. {% if %}, {% assign %}, {% case %}).
Values are transformed with filters, chained with |: 
{{ fields.daily_rate | times: fields.days | plus: fields.cleaning_fee }}
Common filters you’ll use in formulas:
plus, minus, times, divided_by, modulo
{{ fields.rate | times: fields.days }}
round, ceil, floor
{{ fields.total | divided_by: 3 | round }}
default substitutes a value when the input is empty.
{{ fields.rate | default: 0 }}
upcase, downcase, capitalize, append, prepend
{{ fields.sku | prepend: "SC-" }}
date formats a date with a strftime string.
{{ fields.starts_on | date: "%Y-%m-%d" }}
See the Liquid reference for the full list.

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Conditional logic

Use {% if %} to branch. The formula still has to render a value that matches the result type, so return one on every branch: 
{% if item.fields.replacement_cost > 50000 %}true{% else %}false{% endif %}
For more than two branches, {% case %} is often cleaner: 
{% case fields.tier %}
  {% when "gold" %}   {{ fields.base_rate | times: 0.8 }}
  {% when "silver" %} {{ fields.base_rate | times: 0.9 }}
  {% else %}          {{ fields.base_rate }}
{% endcase %}

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Working with intermediate values

{% assign %} lets you name intermediate values so complex formulas stay readable: 
{% assign gross = fields.daily_rate | times: fields.days %}
{% assign discount = gross | times: fields.discount_percent | divided_by: 100 %}
{{ gross | minus: discount }}

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Liquid variable reference

The variables available in a formula depend on the calculated field’s owner. Custom field keys are shop-defined; below they are shown as fields.<key> and metafields.<key>.

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Scalar custom field types

Every fields.<key> variable takes its Liquid type from the underlying scalar custom field definition:
Custom field typeLiquid typeExampleNotes
moneyinteger1500Cents
integerinteger3
booleanbooleantrue / false
single_line_text_fieldstring"hello"
multi_line_text_fieldstring"hello\nworld"
datestring"2024-01-15"ISO 8601 date
date_timestring"2024-01-15T12:30:00"ISO 8601 datetime

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Liquid references by owner

The variables available in a formula depend on the calculated field’s owner. Expand an owner below to see every variable it exposes, along with its Liquid type and where the value comes from.
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fields.<key>
varies
One entry per scalar custom field defined on items, keyed by the definition’s key. The Liquid type mirrors the custom field type: money and integer are integers (money in cents), boolean is a boolean, and text, date, and date_time are strings.
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variant
object
The item’s linked Shopify variant. Only available when the item has a linked variant.
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fields.<key>
varies
One entry per scalar custom field defined on cycles, keyed by the definition’s key. The Liquid type mirrors the custom field type: money and integer are integers (money in cents), boolean is a boolean, and text, date, and date_time are strings.
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item
object
The rented item. Includes the item’s own fields and, when the item has a linked Shopify variant, its variant data.
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fields.<key>
varies
One entry per scalar custom field defined on consignors, keyed by the definition’s key. The Liquid type mirrors the custom field type: money and integer are integers (money in cents), boolean is a boolean, and text, date, and date_time are strings.
More information on using Liquid can be found on Shopify’s developer documentation.

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Allowed result types

A calculated field’s output must match its declared result type. Result types are the same scalar set as the referenceable custom field types:
  • money (stored as cents, e.g. "4500")
  • integer
  • boolean
  • single_line_text_field
  • multi_line_text_field
  • date
  • date_time

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Example formulas

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Miles completed during a cycle (integer)

Set on a cycle. Record the item’s odometer reading at drop-off and return, and store the difference as the miles completed on this cycle. 
{{ fields.odometer_return | minus: fields.odometer_start }}

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Total miles completed on an item (integer)

Set on an item. Accumulate miles across cycles by adding this cycle’s contribution to the running total already stored on the item. 
{{ fields.total_miles | plus: fields.miles_this_cycle }}
Because calculated fields recalculate on demand, click Recalculate on the item’s total_miles field after each cycle to roll its value forward.

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Time to breakeven, in cycles (integer)

Set on an item. Divide the remaining cost to recover (acquisition cost minus revenue collected so far) by the average revenue per cycle, using the Shopify variant’s unit_cost as the acquisition cost and a merchant-managed average_revenue_per_cycle metafield on the product. 
{% assign remaining = variant.unit_cost | minus: fields.total_revenue %}
{{ remaining | divided_by: variant.product.metafields.average_revenue_per_cycle | ceil }}

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Has broken even (boolean)

Set on an item. Flag items whose total revenue has met or exceeded their acquisition cost. 
{% if fields.total_revenue >= variant.unit_cost %}true{% else %}false{% endif %}

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Recalculating values

Calculated fields don’t update automatically when the fields they depend on change. To update a value:
1

Open the record

Open the item, cycle, or consignor that owns the calculated field.
2

Find the calculated field

Scroll to the Custom fields section and locate the calculated field you want to update.
3

Recalculate

Click the field, then press Recalculate. The formula is rendered against the record’s current field values and the result is saved.
If the formula is invalid, or the rendered result doesn’t match the declared result type (for example, the formula produces "abc" for a money field), the recalculation fails and the previously stored value is left unchanged. Fix the formula in Settings > Custom data and try again.