Frozen answers

Built in. frozen belongs to the engine rather than to a package, so it works on any line, whichever packages are registered.

Some answers are live: an exchange rate, a share price or a temperature is fetched when the line is evaluated, so 10 USD in GBP shows a slightly different amount tomorrow. That is right for a line you glance at to see today’s figure, and wrong for an expense claim, a quote or an archived report, where the amount written down is the amount that was agreed.

Ending a line with frozen keeps its first answer. The first time the line settles on a value, the engine stores that value together with the moment it was fixed, and from then on answers with the same amount without asking the provider again. The line below is live, so its amount depends on the day you read this page; the point is that it stops depending on the day once it has answered.

10 USD in GBP frozen

Line	Before	Now
10 USD in GBP	today’s rate, and next month’s rate next month	unchanged: a line without frozen still follows the rate
10 USD in GBP frozen	Unexpected token after expression: "frozen"	today’s rate, kept, with the date it was frozen

The answer carries its date and where its figures came from (the rate’s provider and when it was fetched), so an app can show “frozen 23 Sep 2026, reference rate” beside the line. See async and live data for how a host reads them.

Lines built on a frozen answer

A frozen line can be read like any other: by a later line, or through a variable it defines. Those later lines compute from the frozen amount, so they do not move either. frozen works on any answer, live or not; freezing a fixed calculation changes nothing about it, which makes it a convenient way to see the shape:

:deposit = 250 * 4 frozen // 1,000
deposit + 50 // 1,050

With a live figure the same shape keeps a rate for the rest of a note:

:rate = 1 USD in GBP frozen
120 USD in GBP
120 * rate

The second line follows the market and the third does not. A line computed from a frozen answer is not itself marked frozen, because it is a new value, but it carries the frozen rate’s record, date included, so an app can still show which lines depend on it.

Naming the day

A bare frozen fixes the answer the first time the line settles in the engine that evaluates it. A note sent to someone else, or opened on another machine, arrives as text: if the stored answer does not travel with it, the line would be frozen afresh at that day’s rate, and the note would read differently without saying so.

Naming the day closes that gap. frozen on 2026-09-23 says the answer was frozen on that day, so an engine that holds a value frozen that day answers with it, and one that does not refuses the line by name rather than freezing a new one. Writing today’s date freezes the line now, as a bare frozen does.

10 USD in GBP frozen on 2024-01-15 // ERROR: This line was frozen on 2024-01-15, but no value frozen that day is stored in this engine. A frozen value is never fetched again: restore the snapshot or frozen values it was saved with, or remove "on 2024-01-15" to freeze it anew.

This is a different question from 100 USD in GBP on 2024-01-15 on the currency page. That form asks a historical provider for the rate on a past day, which is how a note converts at a day it was not written on. frozen on fetches nothing: it reads back an answer this engine, or a snapshot of it, already holds. The date after frozen on has to be a date, at the end of the line:

10 USD in GBP frozen on tuesday // ERROR: "frozen on" needs the day the answer was frozen, written as a date at the end of the line, as in "frozen on 2026-09-23".

Where the answer is kept

A frozen answer is kept by the engine that froze it, under the line’s text (without the word frozen, and with spacing ignored), so two lines that say the same thing share one answer. An app that saves an engine snapshot saves its frozen answers with it, and a snapshot restored later answers the same lines with the same amounts, with the network switched off if need be. Clearing the engine for a new document forgets them, and an app can forget one on purpose so that its line freezes again. The embedding guide covers the snapshot.

What frozen does not do

• It freezes a whole line. The word goes at the end, after everything the line computes; there is no way to freeze half of a line. Split the part to keep onto a line of its own.
• It needs one answer to keep. A function definition or a global cell cannot be frozen, and neither can a line that defines a value part-way through; each is refused by name.
• It waits for a settled answer. A line still fetching is not frozen until its value arrives, and a line that fails (no rate, network switched off) is not frozen at all, so it can still freeze once it succeeds.
• It does not refresh. A frozen answer never moves on its own. To take a new figure, remove frozen, change the line, or have the app forget the stored answer. Editing the line’s text freezes it afresh, since it is now a different line.
• It keeps the word. At the end of a line frozen is the suffix, so a variable called frozen there needs its operator written out: 2 * frozen multiplies, 2 frozen freezes 2.

f(x) = 2x frozen // ERROR: frozen keeps a line's answer, and a function definition has no answer to keep. Freeze a line that calls the function instead.