In article ,
writes:

I want to determine the radius vs time for the universe (observable
today) but using universe ages starting with age =3D 0.721 Gyr and
moving forward in Gyr increments. Ned Wright's calculator gives values
but from our current perspective, looking outward into the surrounding
universe, whereas I want to go back in time and am not sure I can use
the values.

Using the calculator, I got the below values for radius of the universe
as a function of the distance out I look using z values to give Gyr
increments with default settings for co moving radius:

If I did this right, the following are the co moving radii for the
universe out to the same co moving radius (that we see today) applied
to different ages of the universe starting at 0.721Gyr and increasing by
1Gyr per data point up through present at 13.721Gyr.

I'm not completely sure what you want. If you take the current radius
of the observable universe (the present proper distance to the particle
horizon---you need to understand all these terms to make progress) and
want to know the distance to an object which is now at the particle
horizon for times in the past (as opposed to the size of the particle
horizon back then; an object at the particle horizon now would, in
general, have been outside it in the past), then that is easy: just
divide by (1+z). Just don't confuse this with the speed of light
multiplied by the lookback time, nor with the luminosity distance, nor
with the angular-size distance, nor with the proper-motion distance, nor
with the parallax distance, nor with the scale factor of the universe.