टेम्पलेट:Inflation/doc

This template calculates inflation based on several inflation index data sets. The template uses an identification code for an inflation index (usually a country code), an original value, an original start_year and either a specific reference end_year or by default the latest currently available end year, and calculates the equivalent value from historical economic changes between the original and reference years. For example, this template calls the United States inflation table located in the sub-template Template:Inflation/US/dataset to perform the U.S. calculation.

Aside from a convenient way to calculate values from different specified time periods, this template allows a regularly automatically updated calculation of value based on the most recent available inflation data. Whenever inflation tables are updated, potentially annually, all articles using this template have their displayed values updated accordingly.

Usage

{{Inflation|index|value|start_year}}
{{Inflation|index|value|start_year|end_year}}
{{Inflation|index|value|start_year|r=decimals|fmt=c}}
{{Inflation|index|value|start_year|r=decimals|fmt=eq}}
{{Inflation|index|value|start_year|r=decimals|fmt=eq|cursign=X}}

The supported countries are listed below, with their index and available data periods:

index	Country	start_year minimum	end_year maximum
AU	Australia	1901	2018
AU-road	Australia [...?]	1998	2018
BD	Bangladesh	1986	2014
CA	Canada	1914	2018
DE	Germany	1882	2009
IN	India	1953	2019
IR	Iran	1315	1398
JP	Japan	1946	2019
PH	Philippines	1958	2019
PK	Pakistan	1960	2018
UK	United Kingdom	1209	2019
UK-GDP	United Kingdom GDP deflator	1700	2016
US	United States	1800	2019
US-GDP	United States GDP deflator	1790	2018
ZAR	South Africa	1960	2018
KRW	South Korea	1951	2017

Parameters

• |index= (parameter 1), required, an index code for one of several available inflation indexes.
• |value= (parameter 2), required, original price or value from which to base the inflation calculation on. Will ignore any commas, but must not have a currency symbol.
• |start_year= (parameter 3), required, original year from which to base the inflation calculation on. Must be a year available in the chosen inflation index. As an exception to this, if the current year is specified and no end_year is specified, the template will output value unchanged, as it can be assumed an inflation of zero.
• |end_year= (parameter 4), optional, reference year for which to calculate inflation. Must be higher (later) than start_year, but not higher than the highest (most recent) year available in the chosen inflation index, and will default to the highest (most recent) available year if omitted.
• |r=digit sets the digits to which the value must be rounded. A negative value indicates rounding to an upper significant digit, and a positive value indicates a fractional digit including trailing zeros. Defaults to 0, i.e., without cents.
• |fmt=c will insert thousands separator commas into the calculated value.
• |fmt=eq will show an equivalent-to phrase, in the format, "equivalent to cursignend_value in end_year". Uses thousands separator commas.
  • |cursign= will set the currency symbol to be shown. Only functions when |fmt=eq is used. Can use advanced symbol formats, but can only precede the calculated value. Default is $.

Examples

• Y {{Inflation|DE|100|2000}} →
• Y {{Inflation|US|595|1982}} → 1576
• Y {{Inflation|US|595|1982|fmt=eq}} → equivalent to $1,576 in 2019
• Y {{Inflation|US|800|1942|fmt=eq|r=-3}} → equivalent to $13,000 in 2019
• Y {{Inflation|US|100|2010|2012|fmt=eq|r=2}} → equivalent to $105.28 in 2012
• Y US$595 ({{Inflation|US|595|1982|fmt=eq}}) → US$595 (equivalent to $1,576 in 2019)
• Y US$595 ({{Inflation|US|595|1982|fmt=eq|cursign=[[United States dollar|US$]]}}) → US$595 (equivalent to US$1,576 in 2019)
• Y $21 million (equivalent to ${{Inflation|US|21|2005|r=2}} million in {{Inflation/year|US}}) → $21 million (equivalent to $27.49 million in 2019)
• Y {{Inflation|UK|1|1209|fmt=eq|cursign=£}} →
• Y {{Inflation|AU|100|2024|fmt=eq}} →
• Y ${{Inflation|US|100|2024}} in {{Inflation/year|US}} → $100 in 2019

It is possible to use the template in incorrect ways without producing error messages. Please read the warnings and appropriate uses of this template at the beginning of the template description.

• N {{Inflation|UK|10|1971|fmt=eq}} → (Omitting the |cursign= parameter will show the $ symbol by default, which is the wrong currency symbol for British currency)
• Y {{Inflation|UK|10|1971|fmt=eq|cursign=£}} →
• N $595 (${{Inflation|US|595|1982|fmt=c}} today) → $595 ($1,576 today) (Misleading time reference)
• N $595 (${{Inflation|US|595|1982|fmt=c}} in {{CURRENTYEAR}}) → $595 ($1,576 in 2024) (Misleading time reference)
• N $100 (${{Inflation|US|595|1982|fmt=c}} adjusted for inflation) → $100 ($1,576 adjusted for inflation) (Misleading time reference)
• Y $595 ({{Inflation|US|595|1982|fmt=eq}}) → $595 (equivalent to $1,576 in 2019)
• Y $595 (equivalent to ${{Inflation|US|595|1982|fmt=c}} in {{Inflation/year|US}}) → $595 (equivalent to $1,576 in 2019)
• N Jane Doe amassed a fortune of $1 billion in 1975, making her worth ${{Inflation|US|1|1975|fmt=c}} billion in {{Inflation/year|US}}. → Jane Doe amassed a fortune of $1 billion in 1975, making her worth $5 billion in 2019. (CPI is not for personal wealth of the wealthy – use GDP deflator instead)
• N Jane Doe amassed a fortune of $1 billion in 1975, equivalent to ${{Inflation|US|1|1975|fmt=c}} billion in {{Inflation/year|US}}. → Jane Doe amassed a fortune of $1 billion in 1975, equivalent to $5 billion in 2019. (CPI is not for personal wealth of the wealthy – use GDP deflator instead)
• Y Jane Doe amassed a fortune of $1 billion in 1975, equivalent to ${{Inflation|US-GDP|1|1975|fmt=c}} billion in {{Inflation/year|US-GDP}}. → Jane Doe amassed a fortune of $1 billion in 1975, equivalent to $ billion in 2018

Entering invalid parameters or omitting required parameters will result in an error message and categorization into Category:Pages with errors in inflation template.

• N {{Inflation}} →
• N {{Inflation|abc}} →
• N {{Inflation|AU}} →
• N {{Inflation|AU|100}} →
• N {{Inflation|abc|€100|1980}} →
• N {{Inflation|DE|€100|1980}} →
• N {{Inflation|DE|€100|zzzz|zzzz|r=zzzz}} →
• N {{Inflation|AU|100|1200|2025}} →
• N {{Inflation|AU|100|2005|2004}} → (see the Limitations section below)
• N {{Inflation|AU|100|2005|2025|fmt=eq}} →
• N {{Inflation|AU|100|2024|2025|fmt=eq}} →
• N {{Inflation|AU|100|2024|1905|fmt=eq}} →
• N {{Inflation|AU|100|2025|fmt=eq}} →

Tips & tricks

Currency conversion

This template is currency agnostic, which means it doesn't convert between different currencies. Thus, if you wanted to know how much DM 1,000.00 marks in 1960 are worth nowadays, entering {{Inflation|DE|1000|1960|r=2}} would provide a result () still in marks, not in euros.

Consequently, if you need a result in another currency than the one in which the original value is stated, for now you must do the conversion manually, as in the following example which uses the defined conversion rate of € 1 = DM 1.95583:

• Y {{#expr:({{Inflation|DE|1000|1960|r=2}} / 1.95583) round 2}} →

 ToDo A currency conversion template to ease these conversion tasks is planned. This section will be updated accordingly once it's developed.

Non-decimal inputs

The template does not accept non-decimal inputs such as £sd; these must be decimalized beforehand. For example, if you wanted to know the value of three shillings and sixpence (3s 6d) Sterling in 1950 in 2018, you must convert to the appropriate decimal value (in this case £0.175) for use in the template:

• Y {{Inflation|GBP|0.175|1950|2018}} →

For £sd specifically {{Pounds, shillings, and pence}} can be used to convert to decimal; for other non-decimal currencies, such as the old Indian rupee, templates can be made for decimalization upon request.

Rounding

By default the values are calculated to the unit, as for all but very low values cents are undesirable. You can specify rounding with the |r= parameter which determines the number of decimals. To obtain cents use |r=2, but other values can be used, including negative ones: |r=-3, for example, will round to the nearest thousand, |r=-6 to the nearest million, and so on. It is advisable to avoid excessive precision; even if the start value is known to be exact, the template's result will not be because the inflation index tables are rarely accurate to more than about 1%, and a granularity of whole years is used.

Very large results

Very large results are expressed in scientific notation ("1.2E+14" instead of "120000000000000") which is normally not desirable. A workaround is to express the value to be inflated with fewer digits, adding a multiplier text such as "trillion" after the result, using the "Show preview" button as many times as needed, changing parameters until the best result is found:

• Y ${{Inflation|US-GDP|1000000000000|1900|r=-11|fmt=c}} → $
• N ${{Inflation|US-GDP|10000000000000|1900|r=-12|fmt=c}} → $
• N ${{Inflation|US-GDP|10000000000|1900|r=-9|fmt=c}} thousand → $ thousand
• Y ${{Inflation|US-GDP|10000000|1900|r=-6|fmt=c}} million → $ million
• Y ${{Inflation|US-GDP|10000|1900|r=-3|fmt=c}} billion → $ billion
• Y ${{Inflation|US-GDP|10|1900|fmt=c}} trillion → $ trillion

The following section provides an automated way of avoiding this trial and error scenario.

Format price

{{Format price}} is a template specifically designed to display price values, both big and small, in a readable way. For example, instead of showing the whole of a huge number such as "953,783,409,856.12", it would show it as "954 billion", while small numbers have their cents part appearing as expected, "1234.5" being properly shown as "1.23 thousand".

• Y ${{Format price|{{Inflation|US-GDP|10000000000000|1900}}}} → $NaN
• Y ${{Format price|{{Inflation|US-GDP|1000000|1990}}}} → $NaN
• Y DM {{Format price|{{Inflation|DE|1000000|1957|1978}}}} → DM NaN
• Y £{{Format price|{{Inflation|UK-GDP|1000|1323}}}} → £NaN

Documenting

It's a good practice to provide a valid reference for the prices calculated with this template in articles where it's used. The template {{Inflation/fn}} was developed to ease this task. It accepts as its single parameter the same country codes used here, and will generate one or more appropriate footnotes. Typically, this is how a piece of text using it looks like:

• In 1985 a unit cost on average $1,040. This is {{Inflation|US|1040|1985|fmt=eq}}.{{Inflation/fn|US}}

Resulting in this converted code (notice the footnote link at the end):

• In 1985 a unit cost on average $1,040. This is equivalent to $2,472 in 2019.

The footnote thus generated appears whenever {{reflist}} or <references /> is used in an article, usually in its "References" section. See below for the live example in this document's own References section, or click the above generated footnote to jump to it.

Limitations

1. Currently it isn't possible to "de-inflate" a value to what it would have been in a previous year. If you need this functionality, please request it at the talk page. Adding it won't be difficult, but there's no point in doing so before someone actually needs it.
2. Substitution isn't supported at all. Trying to {{subst:Inflation|...}} would only result in a long sequence of embedded parser code without any direct benefit. If you need to obtain an inflated price only once, please use the special ExpandTemplates page then copy the result and paste it at the desired location.

Developer documentation

An inflation series represents templates in the following categories:

• Template:Inflation/index
• Template:Inflation/index/dataset
• Template:Inflation/index/startyear
• Template:Inflation/doc/index (Which is then displayed at Inflation/name/dataset as the documentation, and needs to refer to the original data source)

Modifications need to be made to:

• Template:Inflation/fn
• Template:Inflation/year

Current subpages:

Pages with the prefix 'Inflation' in the 'Template' and 'Template talk' namespaces:

Template:

Inflation

• Inflation/AU-road/startyear
• Inflation/AU/startyear
• Inflation/BD/startyear
• Inflation/CA/startyear
• Inflation/DE/startyear
• Inflation/IN
• Inflation/IN/dataset
• Inflation/IN/startyear
• Inflation/IR/startyear
• Inflation/JP/startyear
• Inflation/KRW/startyear
• Inflation/PH/startyear
• Inflation/PK/startyear
• Inflation/UK-GDP/startyear
• Inflation/UK/startyear
• Inflation/US
• Inflation/US-GDP/startyear
• Inflation/US/dataset
• Inflation/US/startyear
• Inflation/USD
• Inflation/ZAR/startyear
• Inflation/doc
• Inflation/fn
• Inflation/update warning
• Inflation/year
• Inflation/year/doc

Template talk:

TemplateData

This is the TemplateData documentation for this template used by VisualEditor and other tools.

TemplateData for Inflation

This template calculates inflation based on several inflation index data sets. Note that this template defaults to calculating the inflation of Consumer Price Index values: staples, workers' rent, small service bills (doctor's costs, train tickets). For inflating capital expenses, government expenses, or the personal wealth and expenditure of the rich, the US-GDP or UK-GDP indexes should be used, which calculate inflation based on the [[gross domestic product]] (GDP) for the [[United States]] and [[United Kingdom]], respectively.

Template parameters

This template prefers inline formatting of parameters.

Parameter		Description	Type	Status
Index	index 1	An index code for one of several available inflation indexes. One of AU, AU-road, BD, CA, DE, IN, JP, PH, PK, UK, UK-GDP, US, US-GDP, ZAR. Example US	String	required
Value	value 2	Original price or value from which to base the inflation calculation on. Will ignore any commas. Example 1000	Number	required
Start year	start_year 3	Original year from which to base the inflation calculation on. Must be a year available in the chosen inflation index. As an exception to this, if the current year is specified and no 'End year' is specified, the template will output value unchanged, as it can be assumed an inflation of zero. Example 1975	Number	required
End year	end_year 4	Reference year for which to calculate inflation. Must be higher (later) than 'Start year', but not higher than the highest (most recent) year available in the chosen inflation index, and will default to the highest (most recent) available year if omitted. Example 2015	Number	optional
Number of digits	r	Sets the digits to which the value must be rounded. A negative value indicates rounding to an upper significant digit, and a positive value indicates a fractional digit including trailing zeros. Defaults to 0. Default 0 Example 1	Number	optional
Format	fmt	"c" will insert thousands separator commas into the calculated value. "eq" will show an equivalent-to phrase, in the format, "equivalent to (cursign)(end_value) in (end_year)". Uses thousands separator commas. Example eq	String	optional
Currency sign	cursign	Sets the currency symbol to be shown. Only functions when Format "eq" is used. Can use advanced symbol formats, but can only precede the calculated value. Default is $. Default $ Example €	String	optional

See also

• {{Inflation/year}}
• {{Inflation/fn}}
• {{Format price}}
• Category:Currency templates
• Inflation
• Consumer price index
• Consumer Price Index (United Kingdom)
• Harmonised Index of Consumer Prices
• Lists of country codes
• List of circulating currencies
• United States Consumer Price Index
• GDP deflator