Calculating share price from home currency is off by a few cents

For my spreadsheet, I’m trying to figure out the formula to calculate what the share price was for a position using just the price paid in my home currency £GBP and the number of shares.

Example, I bought 0.24390069 shares at $279.54. However when I do this:

£49.91 (Price paid in GBP) x $1.3659 (FX rate at the time of purchase) = $68.172069 (price paid in $USD)

But…

$68.172069 / 0.24390069 = $279.51 (rounded up).

Why isn’t it £279.54? I used FX rate, and not the Base FX rate, which I think is correct?

If I do the calculation in reverse, I do get nearer (£49.92).

You need more decimal points. You’re working from a rounded $49.91 which should be closer to 49.9158. I guess behind the scenes, FT use the more accurate number but only display the rounded amount to 2 decimal places which is pretty normal.

$279.54 * 0.24390069 = 68.179998

68.179998 / 1.3659 = 49.915805