This add-on adds functions to your Google Sheets™ document for currency conversion that use historical reference exchange rates gathered from European Central bank and other sources.  Functions support 40 types of traditional currencies since 2000 and 12 types of cryptocurrencies.

To get started, open your document and select any item in the menu "Add-ons" | "Currency Converter".

Functions:

1. CurrencyConverter 
Converts a given amount from one currency to another for a given date. Currency alphabetic codes should follow the ISO 4217 standard.  For better performance, it is recommended to pass a range of values as input instead of using the function multiple times on a large range of data.

Sample Usage
 =CurrencyConverter(100, "USD", "EUR", "2/28/2020") returns 91.09957183.
 =CurrencyConverter(A2:A41, "usd", C2:C41) returns an array of converted values from US dollar to a range of currencies for the latest available date.
 =CurrencyConverter(A2:A41, B2:B41, C2:C41, "2/18/2019") returns an array of converted values for date 2/18/2019.
 =CurrencyConverter(A2:A41, B2:B41, C2:C41, D2:D41) returns an array of converted values.

Syntax
CurrencyConverter(amount, currencyFrom, currencyTo, [date])
 - amount - The value to convert from OR single-column range of values.
 - currencyFrom - The currency alphabetic code to convert from OR single-column range of codes.
 - currencyTo - The currency alphabetic code to convert to OR single-column range of codes.
 - date - The date to search in rates history OR single-column range of dates. If it is not provided, the latest available date is used.
 - Returns a converted value OR a single-column range of converted values.
Note, in some countries,  arguments in formulas should be separated by a semi-colon (;) instead of comma (,).

2. CurrencyConverter_Currencies 
Gets alphabetic codes of supported currencies for a given date. Currency alphabetic codes should follow the ISO 4217 standard.

Sample Usage
 =CurrencyConverter_Currencies ("2/28/2020")

Syntax
CurrencyConverter_Currencies([date])
 - date - The date to search in rates history.  If it is not provided, the latest available date is used.
 - Returns a list of supported currencies.


Supported currencies:
AED - UAE Dirham, AUD - Australian dollar, AZN - Azerbaijani manat, BGN - Bulgarian lev, BRL - Brazilian real, BYN - Belarusian ruble, CAD - Canadian dollar, CHF - Swiss franc, CLP - Chilean peso, CNY - Chinese yuan renminbi, CZK - Czech koruna, DKK - Danish krone, EGP - Egyptian pound, EUR - Euro, GBP - Pound sterling, HKD - Hong Kong dollar, HRK - Croatian kuna, HUF - Hungarian forint, IDR - Indonesian rupiah, ILS - Israeli shekel, INR - Indian rupee, ISK - Icelandic krona, JPY - Japanese yen, KRW - South Korean won, KZT - Kazakhstani tenge, MDL - Moldovan leu, MXN - Mexican peso, MYR - Malaysian ringgit, NOK - Norwegian krone, NZD - New Zealand dollar, PHP - Philippine peso, PLN - Polish zloty, RON - Romanian leu, RUB - Russian rouble, SAR - Saudi riyal, SEK - Swedish krona, SGD - Singapore dollar, THB - Thai baht, TRY - Turkish lira, TWD - New Taiwan dollar, UAH - Ukrainian hryvnia, USD - US dollar, ZAR - South African rand.
Supported cryptocurrencies:
ATOM - Cosmos, BCH - Bitcoin Cash, BTC - Bitcoin, DASH - Dash, EOS - EOS, ETC - Ethereum Classic, ETH - Ethereum, LINK - Chainlink, LTC - Litecoin, XLM - Stellar, XRP - XRP, XTZ - Tezos, ADA - Cardano, DOGE - Dogecoin, DOT - Polkadot, SOL - Solana.