A column definition sets the attributes of a column. The general definition looks like this:

%[WIDTH]PROPERTY[(TITLE)][{SUMMARY-TYPE}]

Except for the percent sign and the property name, all items are optional. The individual parts have the following meaning:

`WIDTH`An integer specifying the width of the column in characters. If omitted, the width is determined automatically.

`PROPERTY`The property that should be edited in this column. Special properties representing meta data are allowed here as well (see Special Properties).

`TITLE`The header text for the column. If omitted, the property name is used.

`SUMMARY-TYPE`The summary type. If specified, the column values for parent nodes are computed from the children

^{54}.Supported summary types are:

‘ `+`’Sum numbers in this column. ‘ `+;%.1f`’Like ‘ `+`’, but format result with ‘`%.1f`’.‘ `$`’Currency, short for ‘ `+;%.2f`’.‘ `min`’Smallest number in column. ‘ `max`’Largest number. ‘ `mean`’Arithmetic mean of numbers. ‘ `X`’Checkbox status, ‘ `[X]`’ if all children are ‘`[X]`’.‘ `X/`’Checkbox status, ‘ `[n/m]`’.‘ `X%`’Checkbox status, ‘ `[n%]`’.‘ `:`’Sum times, HH:MM, plain numbers are minutes. ‘ `:min`’Smallest time value in column. ‘ `:max`’Largest time value. ‘ `:mean`’Arithmetic mean of time values. ‘ `@min`’Minimum age ^{55}(in days/hours/mins/seconds).‘ `@max`’Maximum age (in days/hours/mins/seconds). ‘ `@mean`’Arithmetic mean of ages (in days/hours/mins/seconds). ‘ `est+`’Add low-high estimates. You can also define custom summary types by setting

`org-columns-summary-types`

.

The ‘`est+`’ summary type requires further explanation. It is used for
combining estimates, expressed as low-high ranges. For example,
instead of estimating a particular task will take 5 days, you might
estimate it as 5–6 days if you’re fairly confident you know how much
work is required, or 1–10 days if you do not really know what needs
to be done. Both ranges average at 5.5 days, but the first represents
a more predictable delivery.

When combining a set of such estimates, simply adding the lows and
highs produces an unrealistically wide result. Instead, ‘`est+`’ adds
the statistical mean and variance of the subtasks, generating a final
estimate from the sum. For example, suppose you had ten tasks, each
of which was estimated at 0.5 to 2 days of work. Straight addition
produces an estimate of 5 to 20 days, representing what to expect if
everything goes either extremely well or extremely poorly. In
contrast, ‘`est+`’ estimates the full job more realistically, at 10–15
days.

Here is an example for a complete columns definition, along with
allowed values^{56}.

:COLUMNS: %25ITEM %9Approved(Approved?){X} %Owner %11Status \ %10Time_Estimate{:} %CLOCKSUM %CLOCKSUM_T :Owner_ALL: Tammy Mark Karl Lisa Don :Status_ALL: "In progress" "Not started yet" "Finished" "" :Approved_ALL: "[ ]" "[X]"

The first column, ‘`%25ITEM`’, means the first 25 characters of the item
itself, i.e., of the headline. You probably always should start the
column definition with the ‘`ITEM`’ specifier. The other specifiers
create columns ‘`Owner`’ with a list of names as allowed values, for
‘`Status`’ with four different possible values, and for a checkbox field
‘`Approved`’. When no width is given after the ‘`%`’ character, the
column is exactly as wide as it needs to be in order to fully display
all values. The ‘`Approved`’ column does have a modified title
(‘`Approved?`’, with a question mark). Summaries are created for the
‘`Time_Estimate`’ column by adding time duration expressions like HH:MM,
and for the ‘`Approved`’ column, by providing an ‘`[X]`’ status if all
children have been checked. The ‘`CLOCKSUM`’ and ‘`CLOCKSUM_T`’ columns
are special, they lists the sums of CLOCK intervals in the subtree,
either for all clocks or just for today.

If more than one summary type applies to the same property, the parent values are computed according to the first of them.

An age can be defined as a duration, using units defined in
`org-duration-units`

, e.g., ‘`3d 1h`’. If any value in the column is as
such, the summary is also expressed as a duration.

Please note that the ‘`COLUMNS`’ definition must be
on a single line; it is wrapped here only because of formatting
constraints.