Your house is showing up very tan on my monitor. If there is gray in it I would like to suggest a mustard yellow.
Of course, a cranberry or burgundy would be nice too.

Hi Ellendi...the granite gray is a sort of tanish gray..definitely more gray than tan though. but it definitely has tan undertones.

Cute house! Perfect color for a red door especially with the black trimmings. Very classic.

I think a deep eggplant would be gorgeous or a deep navy.

BM Classic Burgundy

Burgundy would be the "safe" choice. Mustard or eggplant would be lovely as well, but more daring.

Can you load your photo on something like SW Color Visualizer and play around with some choices?

Looks like the perfect house for a cranberry door to me!

Sherwin Williams Chanticleer Red was my choice for my front door. Even with a gray primer you may need 3 coats.

It is a deep red with no orange undertones.

I think cranberry would look really good! A deep rich blue toned burgundy/red:) Very classic with the black shutters. Pretty home!

Farrow and Ball Brinjal. A little unexpected.

I went through this last year. We also did the Certainteed granite gray. Sorry to say, but I finally gave up and painted the door white. Looks nice, and I am happy with it. I figure I can always repaint, but the process was just taking too long.

I tried a lot of colors, mostly reds and plums. More samples than I care to count. My only suggestion is drive around your neighborhood and really look. I realized that a red door was more common than the white. Seems like 2 out of 3 doors around here are painted some variation of red. I think you also have to be careful with them and granite gray. Its a funny color. A house near me put up kind of burgundy shutters and painted the door the same color. It makes the gray look pink!

I do think your house would be great with red -- perhaps the safer choice as mentioned above, but I'm not a yellow or mustard person, so this is one time I wouldn't be daring. I'd most likely go something in the berry red to eggplant range. I like navy doors (have one myself), but I think your grey is a bit too deep to give enough contrast, and the navy may well read too close to the black shutters.

A red door would be beautiful and in keeping with the more classical elements in your portico! Just to add another color to your pile...this is Pratt & Lambert Vintage Claret 3-13. It was achieved with a tinted primer plus two coats. It's a true deep red with blue undertones.

A couple of recommendations when going dark:
-Definitely use a tinted primer. Otherwise, you may need 4 coats to achieve the richness you're seeing from the paint chip.
-If possible, opt for a good name brand paint. Brush strokes will settle better. It's a little shocking when you first paint it on but it will all settle nicely as it dries.

Good luck!

I think burgundy would be suitable.