# Links, formulas & rollups

Connect records once, then use those relationships throughout your workbook.

A linked-record field refers to a real record, not a copied label. For a customer workflow, keep Customers and Projects in separate sheets and add a Customer link to Projects. Select by record name; opening a link takes you to the connected record. A link can allow one or multiple records and can connect sheets in different workbooks within the same workspace.

## Move through a record and its connections

On a phone, the record’s Details, Related work, and Activity controls jump within the same record. Details returns to its fields and notes; Related work reaches available connections, documents, or email; Activity reaches discussion, versions, and updates. A disabled Related work control means no applicable related section is available.

Open a linked record or collection to inspect the connected work, then use the record back trail to return. Your source workbook, sheet, and saved view remain the working context. A link opens the actual record with its current permissions; it does not create a copy or grant extra access.

## Use reciprocal connections

An explicit reciprocal pair keeps both ends synchronized. Assigning a project to a customer can add the project to that customer’s Projects collection in the same saved change. Reassigning a single link removes the previous backlink. Unpaired links are independent; merely naming two fields alike does not make them reciprocal.

## Calculate from numeric fields

```text
[Quantity] * [Unit price]
([Revenue] - [Cost]) / [Revenue]
```

Formula arithmetic supports numeric field names or IDs in square brackets, parentheses, addition, subtraction, multiplication, and division. A formula is a restricted calculation expression, not a JavaScript program. Calculated values are read-only; change an input field to change the result. Apply currency or percent formatting when it matches the meaning of the number.

## Summarize related records

- Choose the linked-record field that defines the related records.
- Choose count, sum, average, minimum, or maximum. Numeric summaries also need the target numeric field.
- Open the linked collection to check which records contribute. Archived records are excluded from linked summaries.

> **When a result is empty** Check the field references, relationship, numeric inputs, and calculation dependencies. Invalid or circular calculations can display empty. Do not treat an empty result as a verified zero.

Formula and rollup values can appear in views, sorting, search, charts, and documents. Different AI query tools have their own supported aggregate types; a ranked search result alone is never evidence for an exact total.