You can believe it; because its Google's Currency Converter Calculator. It can be used to see changes live for currency and foreign exchange rates with this free currency converter.
Here is the Google's Currency Converter
Open JSON API
Good news is here - Google have a secrete API for Currency Conversion. Its a simple open API you can use for all type of foreign currencies.
How to use it?
If you want currency converter £ to dollars, use it like this -
If you want to calculate currency converter $ to £ -
You can change value of input currency, for example you want to know the value for $100 in India Rupees
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