Help me with my gear ratios

[MrIQR]

I have one sled with 19t/45t, 9t driver and 2.52 pitch, looking to match this gear ratio on my other sled but it has 2.86 pitch and 7t driver.

So question is what gearing will be the same or close with the 7t and bigger pitch?

Got a bit lost trying to search for a formula.

 

[Reeb]

Got Excel? Here you go.

 

[eddy]

Ratio

Close enough will be 21/45 for your application.