Properties and formulas

Updated 12 October 2026

Fields that cascade#

A container declares fields for the items inside it. Those definitions cascade down the tree: a grandchild sees the fields its grandparent declared, as well as its own parent's. Inherited from above shows where each one comes from, and Ignore fields from items above this one stops inheritance at a chosen container.

The server computes each item's effective fields and validates every write against them, so a value of the wrong type is refused rather than stored.

Property types#

Type	Holds
Text	One line of text
Long text	Several lines, kept as written
Number	A number
Select	One of a list of options
Multi-select	Any of a list of options
Date	A day
Date and time	A moment, with its time zone
Date or time	Either an all-day date or a timed moment
Checkbox	True or false
Link	A URL
Picture	An image shown as a cover in galleries
Due date, Start date	Task dates that smart lists and timelines understand
Completion	Whether a task is done
Priority	1 to 4
Estimate	An estimate of effort
Assignee	A workspace member
Reminder	When Nix should remind you
Formula	A value calculated from the item's other fields
Rollup	A value folded across the item's children

A field's key is set from its name when it is first saved. Renaming the label later does not change the key or the values stored under it.

Formulas#

A formula field calculates a read-only value from the item's other fields. Refer to a field by its key in square brackets. Do not start a formula with =.

[price] * [quantity]

Formulas can read fields inherited from ancestors, and other formulas. Nix evaluates each formula after the ones it depends on, whatever order you added them in:

subtotal: [price] * [quantity]
total:    ROUND([subtotal] * (1 + [tax_rate]), 2)

The language is deliberately small and safe. It has numbers, text in double quotes, TRUE and FALSE, the operators + - * / ^ %, text joining with &, and comparisons = <> < <= > >=. Use AND, OR and NOT for logic.

Functions:

Maths: SUM, AVERAGE, MIN, MAX, COUNT, COUNTA, ROUND, ROUNDUP, ROUNDDOWN, ABS, INT, MOD, SQRT, POWER
Text: CONCATENATE, LEN, LEFT, RIGHT, MID, TRIM, UPPER, LOWER, CONTAINS, VALUE
Logic: IF, IFERROR, ISBLANK, AND, OR, NOT
Dates: DAYS(end, start)

Some worked examples:

IF(OR(ISBLANK([price]), ISBLANK([quantity])), "Enter price and quantity", ROUND([price] * [quantity], 2))
IFERROR(ROUND([done] / [total] * 100, 1), 0)
IF([complete], "Done", "Open")
DAYS([end], [start])

A blank number counts as zero in arithmetic. Use ISBLANK when an incomplete row should show a prompt instead.

Errors#

Error	Meaning
#PARSE!	The expression cannot be parsed
#NAME?	A field key or function name is unknown
#VALUE!	A value cannot be used by an operator or function
#DIV/0!	Division by zero
#REF!	A formula field tried to read spreadsheet cells
#CYCLE!	A formula refers back to itself, directly or through others
#LIMIT!	The expression, its text or its work exceeded a bound

The editor checks syntax, function names, argument counts and field keys as you type, and points at the position of any mistake.

Limits#

A formula may be up to 1,024 characters long. All the formulas on one item share a budget of 5,000 evaluation steps. Joined text may be up to 32,768 characters. The language has no network or file access, no clock, no randomness and no scripts, and it cannot read another item by ID. Numbers are ordinary floating point, not exact decimal money.

Rollups#

A rollup folds a field across an item's children on the server: how many, total, average, smallest, largest, any of them or all of them. A project can show the number of open tasks inside it, or the sum of their estimates.

Charts#

A chart view counts items or totals a number field, grouped by a select or placed along a date. It can split a series by a choice field and stack it. Charts are computed on the server over the same permission-filtered rows the other views use, and they say when items fall outside the chosen window rather than leaving them out silently.