Result
Value against money in
What this calculates
DCA (dollar cost averaging) means buying a fixed amount on a schedule, whatever the price. When bitcoin is cheap the same money buys more, which is why the average buy price lands below the plain average of prices over the period. This runs on real historical prices, not an assumed average return: monthly buys land on the first of the month, weekly ones on Monday.
In koruna each buy is converted at the Czech National Bank rate of that day rather than today's — the koruna moved a lot against the dollar over twelve years and a single rate would shift the result by percent. History starts in January 2013: older prices come from exchanges that no longer exist and sources disagree by tens of percent.
Broker and exchange fees are not included, and on small recurring buys they typically take half a percent to two percent of each deposit; neither is tax on selling. And past returns say nothing about future ones — over the window you pick, anything can come out.