Rollup - Blue Docs

Rollup custom fields summarize data from records linked to this one and show the result as a single value. Where a Lookup field surfaces the individual values from linked records, a Rollup aggregates them — the total budget across a project’s tasks, the number of open bugs on a release, the average deal size across a customer’s contracts, the latest activity date across a set of records.

Rollup fields are read-only. Blue computes the value automatically and keeps it current as the linked records change.

Pro feature

Rollup fields are available on the Pro and Enterprise plans.

Choosing what to roll up

A Rollup aggregates over a set of linked records, so it always sits on top of a relationship field. You can source the linked records from either:

A Reference field — the records this record points to (e.g. the tasks selected on a project).
A Referenced By field — the records that point back at this record (e.g. every order that references this customer), including records across other projects.

You then pick the field on those linked records to aggregate, and the function to apply.

You can also add an optional filter so the rollup only counts the records you care about — only open tasks, only this quarter’s deals, only records assigned to a specific person. The filter uses the same advanced filter builder as saved views, so any condition you can express in a view, you can apply to a rollup.

Aggregation functions

Function	What it does
SUM	Adds up the values across linked records.
AVERAGE	The mean of the values across linked records.
COUNT	How many linked records there are in total, whether or not the chosen field is filled.
COUNTA	How many linked records have a value in the chosen field — only the non-empty ones.
MIN	The smallest value, or the earliest date.
MAX	The largest value, or the latest date.
ARRAYJOIN	Joins the values from every linked record into a single comma-separated list.

COUNT vs COUNTA

COUNTA works like the spreadsheet function of the same name: it counts only the linked records where the chosen field has a value. COUNT counts every linked record, filled or not.

What each function can roll up

The function you pick determines which field types you can aggregate:

SUM, AVERAGE — numeric fields: Number, Currency, Percent, Star Rating, and Duration.
MIN, MAX — the same numeric fields, plus Date (earliest / latest date).
COUNT, COUNTA — any field type, since they count records rather than aggregate a value.
ARRAYJOIN — text and choice fields: single- and multi-line text, single- and multi-select, email, URL, country, and phone.

Examples

Project budget — on a Project record with a Reference to its Tasks, SUM the Cost field to see total spend, filtered to tasks that aren’t cancelled.
Open bugs per release — on a Release record, COUNT a Referenced By field pointing at the Bugs project, filtered to status “Open”.
Customer lifetime value — on a Customer record, SUM the order total across every order that references the customer.
Next deadline — MIN the Due Date across a project’s open tasks to surface the next thing due.
Team on a project — ARRAYJOIN the Assignee names across linked tasks into a single readable list.

Behavior

Rollups are computed in the background and refresh automatically whenever the linked set changes or one of the aggregated values is updated — there’s nothing to recalculate by hand.

A few things to know:

One currency per rollup. When you SUM or average a Currency field, every linked record must use the same currency. The result is shown in that currency. If the linked records mix currencies, the rollup can’t produce a meaningful total and will flag that instead of silently adding unlike amounts together.
Read-only. A Rollup value can’t be edited directly; change the underlying records and the rollup updates itself.
Reconfigure if the source changes. If the Reference or Referenced By field a rollup depends on is deleted, the rollup will indicate that its source is no longer valid — point it at a new source to restore it.