My bike computer says to match the tire circumference. My tires are etro = 622x19 32H...not matched on the computer...My tire says 37-622 / 700x35. My computers closest match is a 700x35c...So do I set my computer to a 700x35c even though my tire says 700x35?..

First, know that the listed size on tires can be very different from the actual size. Second, the number that is entered into the bike computer is the circumference of the tire (in millimeters [mm]). The computer manufactures essentially covert a tire size (for example 700 x 35) into a corresponding circumference. But if the actual tire size is not the stamped size, then using the number published by the computer manufacturer is going to be wrong.

Not to over analyze it, but what I have done to get around this is to actually measure the tire circumference and enter that value into the bike computer. How do I measure the circumference. Simple, I lay out a tape measure on a flat surface. Then I position my tire next to it, with my valve stem next to the end of the tape. I then apply some pressure to the handlebars (have to apply weight otherwise you are measuring an unloaded wheel) and walk the bike next to the tape for 3 wheel revolutions. I read the inches where the valve stem falls next to (in the same position as when I started (usually straight up). I generally do this 2 or 3 times to verify I get the same distance (or you can average them if the distances are slightly different). Then take the inches, divide by 3 (or how ever many times the wheel completed a full cicle), and multiply by 25.4 (conversion from inches to millimeters). You can compare that to what the computer manufacture says but don't be surprised if they are off by 20 or even 30 millimeters.

Setting the computer for a 700x35c would be fine. Even better, see how far the tire rolls in one revolution, say from valve stem down to valve stem down again. Most bike computers should allow you to input the length directly. In millimeters, it will probably be in the 2110 - 2130 mm range.

Or you could measure the diameter (distance from ground to top of tire and multiply by pi. (C=D(pie)). If you don't have pie on your calculator, just use 3.1416.
Basicly the "700" is the common number for describing the size of your wheel in centimeters the second number is the cross section of your tire in centimeters. Or "35c"

A 12" ruler only has about 31cm on it! Pretty fat bike tire.
PI, not pie.

A 700 x 35 or 35-622 tire has a 622mm bead seat diameter. 35mm is the nominal tire width.
https://www.sheldonbrown.com/tire-sizing.html

It's Pi! It's cake! I'm so confused...

Could be pie...

wait, isn't 700x35 the same as 700x35?

recently read about using a string. tape one end on tread then wrap tire w it and mark where ends meet. then measure with a metric tape measure. should be close enough

No, that is your rim, not your tire. 622 = bead seat diameter in millimeters, 19 = inside rim width, 32H = 32 holes for spokes.

The numbers are millimeters.

"c" isn't referring to a unit of measure, it's just part of the old French rim size system.
The number (700) refers roughly to the inflated diameter of a wheel in millimeters, and the letter (c) refers to tire width. A 700a rim would be a very wide-diameter rim with a narrow tire, a 700b rim would be lower-diameter and would be fitted with a wider tire, etc.
Today, most of the old French sizes are obsolete, and nobody cares about matching that 700mm inflated diameter. So, "700c" now just refers to a rim diameter. In particular, a 700c rim is a rim with a bead seat diameter of 622mm.

A correct description for a 35mm tire on a 700c rim would be 700c x 35mm. Or, in a perfect world where we just drop the nonsense and use ISO sizes, we could call it 35 - 622.

Moving the c to the tire width ("700x35c") is abbreviation slang. And because 650c isn't currently very popular, people sometimes drop explicit references of the tire diameter entirely, and just say "35c." Which, when you think about it, is a remarkably indirect way to describe a tire's dimensions.

Unfortunately, I'm not sure I've ever seen someone try to append a "c" to an imperial tire width measurement, and just use that to describe tire size.

So my rims are 275 inches in diameter?