XLSForm Default Values: Static, Today and Dynamic

An XLSForm default value goes in the default column: type the answer the question should start with, such as 1 for a choice named 1 or today() for a date. ODK Collect, KoboToolbox and SurveyCTO show it pre-filled, and the enumerator can change it. A default that depends on an earlier answer is different: it needs the calculation and trigger columns, because the default column is read when the form opens, before anything has been answered.

Download example form (.xlsx)All seven examples in one XLSForm, one group each. Tested with pyxform and ODK Validate; free to reuse under CC BY 4.0.Download

How do I set a default value in XLSForm?

Add a default column to the survey sheet and type the value as you would store it:

type	name	label	default
text	country	Country of the survey	Bangladesh
integer	visit_number	Visit number	1
date	interview_date	Date of the interview	2026-11-12
select_one yes_no	consent	Does the respondent agree to take part?	1
select_multiple water_source	water_sources	Which water sources does the household use?	1 2
decimal	rice_price	Price of rice per kg (BDT)	51.5

◀ ▶surveychoicessettings+

list_name	name	label
yes_no	1	Yes
yes_no	0	No
water_source	1	Piped water
water_source	2	Protected well
water_source	3	Surface water

◀ ▶surveychoicessettings+

Four rules cover most cases:

• Choices use the name, not the label. 1 selects "Yes". Typing Yes compiles but selects nothing.
• select_multiple takes several names separated by spaces: 1 2 ticks piped water and protected well.
• Dates are YYYY-MM-DD. The date shows in the phone's own format, but the default is always written as 2026-11-12.
• No quotes. The text is taken literally, so Bangladesh, not 'Bangladesh'.

A default is a starting point, not a fixed value. If the answer must never change, use a calculate row instead, or add read_only set to yes.

How do I default a date to today or the current time?

Write today() in the default column of a date question, or now() on a dateTime or time question:

type	name	label	default
date	visit_date	Date of the visit	today()
dateTime	arrival_time	When did you arrive at the household?	now()
time	start_clock	What time did the interview start?	now()

◀ ▶surveychoicessettings+

The value is set once, when the form is first opened, and stays editable. That suits a visit date the enumerator may backdate after a day without signal. If you only need to record when the interview happened, without a question, use the today, start and end metadata types instead: they are filled automatically and cannot be edited.

How do I set a default from an earlier answer?

Put the expression in the calculation column of the visible question and the earlier question in the trigger column. This bed net question starts with the household size, and the enumerator lowers it when fewer people slept under a net:

type	name	label	calculation	trigger
integer	hh_size	How many people live in this household?
integer	slept_under_net	How many of them slept under a mosquito net last night?	${hh_size}	${hh_size}

◀ ▶surveychoicessettings+

Each time hh_size changes, the calculation runs again and fills slept_under_net. If the enumerator then types 4, the 4 stays, until hh_size is changed again. The question used as a trigger must have a label: a calculate row is refused (see the table below).

A trigger can also list several questions, separated by commas. The calculation runs when any of them changes. coalesce() keeps the total working while one count is still empty:

type	name	label	calculation	trigger
integer	adults	How many adults (18 or older) live here?
integer	children	How many children (under 18) live here?
integer	hh_size	Household size (adults plus children, change if needed)	coalesce(${adults}, 0) + coalesce(${children}, 0)	${adults},${children}

◀ ▶surveychoicessettings+

A list of triggers needs ODK Collect v2025.4 or later. A single trigger works from Collect v1.24.

Why not just use the calculation column?

A calculation on a visible question without a trigger is recalculated every time the form changes and again when it is saved. The enumerator can type over it, but the calculated value comes back, and that is what the server receives. The trigger column changes this: the calculation only runs when the trigger question changes, so the enumerator's edit is kept.

Some older forms wrap the expression in once() for the same effect, as in unique IDs. once() stops after the first value, so if the earlier answer is corrected, the default does not follow. Use trigger for defaults.

How do I reuse the answer from the last saved form?

Write ${last-saved#question_name} in the default column. Each new form then starts with the value from the last form saved on that phone, which saves typing on details that rarely change during a day of fieldwork:

type	name	label	default
text	village	Name of the village	${last-saved#village}
text	enumerator_name	Your name	${last-saved#enumerator_name}

◀ ▶surveychoicessettings+

The very first form on a device starts empty, since nothing has been saved yet. Only typed values are copied, never photos or other files. Last-saved needs ODK Collect v1.21 or later.

How do I copy the answer from the previous repeat?

Inside a repeat, a default is calculated each time a new instance is added. This expression takes the same question's answer from the instance just before it:

type	name	label	default
begin_repeat	plot	Plot
text	main_crop	What is the main crop on this plot?	${plot}[position() = position(current()/..) - 1]/main_crop
end_repeat	plot

◀ ▶surveychoicessettings+

Replace plot with your repeat's name and main_crop with the question's name, in both places. The first plot starts empty, and every next plot starts with the crop of the one before. When the question sits in a group inside the repeat, add one /.. per group and put the group in the path, as /g_details/main_crop. To read a repeat's answers from outside it, see indexed-repeat().

How do I clear an answer when an earlier one changes?

Use an empty calculation with a trigger. Here the notes about the water source are cleared whenever the enumerator picks a different source, so notes about a well never end up next to piped water:

type	name	label	calculation	trigger
select_one water_source	main_source	What is the household's main source of drinking water?
text	source_notes	Notes on the main source	''	${main_source}

◀ ▶surveychoicessettings+

list_name	name	label
water_source	1	Piped water
water_source	2	Protected well
water_source	3	Surface water

◀ ▶surveychoicessettings+

Common default value mistakes and how to fix them

These are the results from pyxform and ODK Validate, the same checks ODK Central and KoboToolbox run on upload:

You wrote	Write instead	What you will see
${hh_size} in default	${hh_size} in calculation and in trigger	No error, but the question opens empty
Yes as the default of a select	1 (the choice name)	No error, but nothing is selected
TODAY()	today()	cannot handle function 'TODAY'
A calculate row in trigger	A question with a label	The question ${hh_calc} is not user-visible so it can't be used as a calculation trigger
A misspelled name in trigger	The exact name	the 'trigger' value is invalid. Reference variables must contain a name from the 'survey' sheet
A calculation on a visible question, no trigger	Add the trigger column	No error, but the enumerator's edit is overwritten

The first two rows are the ones to watch for, because nothing tells you about them. For other messages, see common XLSForm errors, or paste your form into the free XLSForm validator.

Does this work the same in ODK, KoboToolbox and SurveyCTO?

The default column with fixed values and today() works the same on all three. The other features come from ODK's side of the XLSForm standard:

Platform	Where defaults go	Notes
ODK (XLSForm)	default column; calculation plus trigger for earlier answers	trigger needs Collect v1.24 or later, last-saved v1.21 or later
KoboToolbox Formbuilder	Default response box in the question's settings	Fixed values; for trigger and last-saved, upload an XLSForm
KoboToolbox (XLSForm upload)	Same as ODK	Test triggers in both Collect and the web form
SurveyCTO	default column	Expressions in default are calculated the first time the field is shown, then left to the enumerator

Because SurveyCTO calculates a default when the field is first shown rather than when the form opens, ${hh_size} in its default column does pick up an earlier answer. The same form in ODK opens that question empty. trigger and ${last-saved#...} are defined by ODK: test them in SurveyCTO's form tester before you rely on them there.

When a default helps and when it hurts

A good default removes typing for an answer that is almost always the same: the country, today's date, the village for the rest of the day. A careless default creates answers nobody gave. If "Yes" is pre-selected on a consent question, a rushed enumerator can swipe past it, and the data shows consent that was never asked for. Keep defaults off consent, eligibility and any question the respondent must actually answer. For the rest, a default in the form beats a fill-down in Excel after fieldwork, because the enumerator sees the value and can correct it on the spot. The XLSForm calculations guide has more patterns for values the form works out for you.

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Next: XLSForm calculation examples →