A 12 cog for the smallest cog? Do you have a 7 speed, and what cog teeth counts?

Here's the Mike Sherman Gear calculator for 35,42,53 and 12-24 in 7 speed: Calculator link

The popup message is just telling you that you can bookmark the page to recall it later. You can change gears or cadence and the charts update on the fly.

From the calculator. 53 in blue, 42 in black, 35 in red. That 35-42 set doesn't offset very far, but does have some good half step gears.