Me and a cofounder have created a free tool that we think will be useful to the BitCoin community.
If you're making many purchases/transactions with BTC, on multiple different dates, it may be difficult to quickly understand what these transactions all mean in terms of a traditional national currency like USD or EUR, due to the high volatility of the exchange rate. This is especially a problem when your BTC transactions need to be officially reported (e.g. expenses for tax purposes, or for corporate expense reimbursement), since reporting in BTC is typically not allowed.
Our free, one-page tool at
http://currency.foxjump.ca tries to solve this problem: You simply copy a spreadsheet region (from Excel, Google Spreadsheets, OpenOffice, etc) containing a column of dates and a column of amounts, and paste it into the tool. Select "BTC" as the "From" currency and your desired national currency as the "To" currency. The tool will then convert
all the amounts at once,
using the correct exchange rate for each date. You can paste the results back into your spreadsheet.
The tool works with all currency pairs (not just Bitcoin), and also calculates totals and the effective exchange rate that you actually had for all your transactions.
The data comes from openexchangerates.org, which means that BTC pricing data ultimately comes from coindesk.com.
Any feedback on the tool and suggestions for improvements would be greatly appreciated!
