You can't put a larger column on a 12 inch wide base. If you go to a 12" column you'll have to enlarge the base.

I'd say yes -- too small.

It still not too late to alter the bases. I could make them larger in depth and height if needed to support a larger column.

I would recommend if the column is square or round to have a square base as well. With these narrower columns I would limit the base to roughly 4" wider than the column in each direction (8" total), rounding to whatever size will give you whole bricks, so that there isn't an issue with proportions. A thicker column (greater than 12") could handle a base that is 6-8" wider than the column width on each side.

As PPF points out, a 10" column seems too slender especially in comparison to the size of the gable that they are visually supporting.

Is it too late to suggest a simple, smooth white Tuscan order column, which is tapered. A 12-inch diameter base, which will have a smaller diameter at the top, and whatever is needed for a proper sized brick base.

Maybe no brick base and bigger columns?

By all means, larger diameter and tapered--not straight--columns. I encourage you to forget about the dentils at the front entry, too. They're not on any other portion of the home and they detract rather than add.

Good catch Charles.

Agree with Charles. Are those shutters on just one window (bottom middle?) Also the keystone above the garage isn’t carried i any of the other arches?

The way I size columns is for every foot of height I add 1" to the column diameter. So if you have an 8' porch I go with a 8" column. In your case I would measure the remaining height from the column to the top and base my column diameter on that dimension.

Good luck

Not sure the height in feet, then converted to inches works. Here's the classical orders. As can be seen the shortest column (Tuscan) is one of the widest.

Not all columns are classical, or fall within a generic sizing algorithm.

We find the classical orders are a good guide for determining eye-pleasing dimensions of round and square columns and for guiding the selection of interior trim in traditional homes. I concur that their application isn't universal; Craftsman style came along a lot later.

For what it's worth, my eye still prefers dimensions of tapered columns that relate well to the structure they support. In the case of PFF's upper photo, I think they relate well. By contrast, the lower photo shows massive columns supporting a simple, light porch roof which looks out of proportion to me.

Yes, I agree. Columns remain as much art as science. And they certainly vary with architectural style.