Genuinely, it depends on my mood a lot, which is frustrating. But I can take anywhere from start to finish 6 hours for about 5 panels in a page, and other times, it takes me like 15 hours. haha. I can tell you on average it takes about 10 hours from start to finish.
But I feel like it's important for you to notice how much detail and effort you're putting into a piece. Personally, I put way more time and effort into something that's not specifically a comic page, but more like a stand alone piece. This pic below is fairly simple in concept, but I took a lot of extra time with the angles, hands, detail work, and coloring. This piece took about 3 hours.
(They get cut off, click to see full images)
Meanwhile, this whole set of pages including backgrounds and stuff took about 6 hours, which is double the time, but also more than 3 times as much stuff on the page. Basically, I put less details in comic pages and care way less about things being perfect, I just need it to be done.
Hey this tracking thing is neat. Is it an app? How did you make it?
I'm always looking for new and better ways to track how long it take me to finish a stage of art.
Edit: I'll be back when I'm more awake to try to show how long a thing takes for me to draw.
Well, I draw pages in batches so I don't really know how long it takes me to draw one page. Usually I'm doing four pages at once and one day it's sketches, next day lineart, then colors and whatever. I guess it's safe to say I can do four pages per week.
I'm pretty fast but I procrastinate a lot. 
HI 
yup it's an app. the name is toggle (https://toggl.com/9). It's not the absolute best app to track, but it's enough for small private projects and it's free
It really depends how i fell a given day,on a good day it takes a day to make a page. on a less good day only few panels or some writing
40 - 50 hours for a 40+ panel vertical comic, but that excludes writing and scripting. I'm experimenting on which corners to cut so I can do them faster .
A script for 1 episode can take me 3 days because I do a lot of edits and rewrites 
Theres a popular saying "The only thing better than perfect is done" Im kinda taking the opposite approach.
I start with a classical finearts foundation and take a more experimental and present moment development path. My laat page I spent 3 weeks sketching out 4 panels, scrapping them doing a month of research and reflecting, than maybe 3 weeks redoing a fresh new set of panels. The potential for my art feels greater to me this way.
I can't compete with modern comic artists. But it's kinda cool to see how my approach that is so taboo to how comic art is made, comes off to my readers as unique and vibe.
Its more of an accomplishment to me than being a professional or accepted comic artist.
I don't like the pressure to draw and upload constantly, so I make a hiatus between chapters to plan the whole chapter and sketch all the pages in advance lol
I take like a month just to work on stript, character/background/colour design, thumbnails, page layouts, and sketches of all the pages (about 20~30?). Then, I take another week to add lineart, colour and text for 4~8 pages before starting to upload so I can have a buffer, and after I start uploading I finish like 2 or 3 pages per week. When I finish the chapter, I take a break to start working on the next chapter or in another comic and repeat the cycle 
But in general what takes longer for me is writing the script, I'm still not very confident in my writing and I rewrite a lot to try to fit the text better in the page. I work a lottt faster on textless comics.
This is a bit of a sore point for me, I am a very slow artist. Until recently I was drawing everything in ink and watercolours. The actual drawing for me was always a very slow process, I've always watched in awe at how other artists seem to be able to just go swoop swoop swoop with their pen and boom, perfect drawing on paper.
For me the problem was made worse by my choice of using watercolours. I'd put a colour down then have to wait for it to dry before I could continue. The comic I've recently started on here has the front cover in watercolour, but I soon realised that it was just going to take too long to do each page so have recently invested in an iPad Pro and am teaching myself to draw watercolour-like pages on it instead. The result is that I'm actually managing a couple of pages a week, whereas that front cover took a week to finish between work and family. I'm still slow, but I know I'll get faster with more practice
I'm such a slow worker. It takes me 1-3 days of work to finish a page, and my style isn't complicated or even all that good lol of course, my 'days' are limited to weekends and what little time I can snatch after work each day. I guess it's no surprise I burned through my buffee as quickly as I did. Such is the curse of a full-time job
potentially at the cost of quality i am FAST. at least for a webcartoonist.
my fastest chapter of TWAW was... perhaps 4-5 weeks of production, working 2 days a week? so, 4 days of writing & drafting, 2 days pencils, 1 day inks, 1 day colours - 18 pages. i cant do the math to break that down into time per panel, but its speedy
The fastest episode I've made so far was made in exactly two weeks, which is about 30-40 panels. And that was during a time when I haven't had school yet. Longer episodes (about 50+ panels) take like three weeks.
That was me for the longest time but I just did it with pencil and added contrast after scanning to make it somewhat look like it was done with pen, haha. I couldn't work with pen, I don't have a stable hand and my hand strokes are short so sketching feels a lot more comfortable to me. Actually, one of the things I like most digital is the resizing feature. I often have the head too big or neck too long in my case. Also bending arms around to not look as awkward. In traditional you more or less have to erase/redo the whole thing.
Slow, so slow it's annoying me. I think it's because I love details and complicated designs that take forever to draw, lineart and color. Also because I draw traditionally and color digitally I have to scan large files and these magnify the workload.
I'm also a neanderthal and don't use express keys on my drawing pad or shortcut keys in general (other than the super obvious ones). Half of my digital time is wasted on trying to find the correct brush or eraser.
I'm in the medium-slow range. Each page takes around 5-8 hours to complete, but I can expedite that somewhat working in batches. (break down is like 30 mins - 1 hour sketching, 1 - 2 hours inking, 1-2 hours flatting, and a few hours shading, effects, lettering. So like not bad by any means. If I really buckle down and focus I can get like 2-3 pages done in a week around my other work. Most weeks I take it easy and just do 1-2 pages because I like to relax and play videogames sometimes after work, or like meet up with friends or whatever. My "peak" productivity rate leaves me with virtually no free time other than maybe friday night and breaks throughout saturday and sunday which is a drag.
My speed has gotten quite a bit better since I started a year ago, I will say. Getting even a single page by itself out in a week used to be a huge undertaking, like if I didn't start sketching Sunday evening I may or may not finish by the following one. Now I can like start Wednesday and comfortably finish by Sunday afternoon if I need to.
I'm still aiming to train my speed a lot before diving into any long-form story though. I don't feel like I'm there yet to finish something of like... 10+ chapters in a reasonable time frame. So I'm sticking to short stories for now and gonna try and work my way up 
I have a long-form I've been slowly writing and would like to start sometime "soon" (next few years?) so we'll see~
klf;djklajkf;dsajfsa; I do this too, I'm so over it LOL I draw on 11x17 paper rn and have just an 8 1/2x11 scanner, each page takes FOUR scans to catch all of the details in the middle (logic would dictate that it would only take 2... that ends up leaving a small line missed in the middle of the page x__x). I'm committed to finishing out the comic I'm currently doing with this work flow just because I'm so close to the end, but I'm so SOOOO moving to all digital for the next one LOL I think traditional inking is cool and still use it for like marker illustrations and stuff, but I'm never (edit: well never say never I suppose, but not for a long while at least) going to use it for a comic of over like 15 pages again 
I'll be honest, I have no sense of time after 16 years of drawing, but I've been told I work fast. So yes, I've improved over time by just... not stopping xD.
There are so many factors involved with speed though, from whether or not you're used to drawing the characters, how efficiently you use your art tools, and distractions in your workspace. There are 2 ways to get faster: Learn to draw faster and Eliminate wastes of time (distraction, switching between tasks too quickly as that slows you down, learn all the keyboard shortcuts).
My current rate is somewhere about 1-2 hours for a completely rendered complex panel. When batching together panels of 5 or more, the rate goes down because doing one stage at a time helps you focus in and avoid wasting time by switching tasks (going from sketch to line to color are three different modes of work, for example). So generally for story segment that 45 panels long, that'll take me 45 to 55 hours to complete. Working just 3ish hours a day cause I have 7 ongoing projects means one episode takes 15 - 18 days, so 3ish weeks.
I simplified the way I shade to save time too, an example of a Chapter title page:
Thumbnail (few minutes)
Pencils (I made two different sketches in fact so up to 30 minutes or so, fast and loose; by this point I had made a lot of concept art drawings of this character so i got used to drawing him and that speeds up the process too)
Inking (up to 30-40 minutes? I saved time by filling in darker areas for high contrast and depth+ save time shading; my favorite step)
Flats (Longest step but I did my linework on two layers, Outlines for major color sections on one and details on another so filling in flat colors is fast. that's another way to speed up flat coloring, but it takes some discipline with lines.)
Render (Shading and lighting, trying to stick to a bare minimum needed to add some depth to the coloring. using one shade hue per color area (but with a brush on opacity pressure so I can have sharp shadows within lighter general shadows) and gradient lighting over the whole thing for ambiance.)
Some background:
Been drawing for 16 years self-taught
Been to college for art/animation -4 years of drawing and design-related classes
Been actually finishing comics only in the last few years, two one-shots and one premium comic.
My entire goal in college was to learn to draw fast and accurate. Drawing well and drawing fast are like a venn diagram with a number of factors that affect each side. You slow down to learn to draw well (learning anatomy, lighting, the theory), then you take what you learnt and practice doing it as fast as possible while gradually slowing it down in a session (About ten 10-to-30-second Gesture drawings, and five 1-minute , three 5-minute , and one 10-minute drawings is a classical way to practice)
There's a difference between training to get faster and just getting ambiently faster because the longer and more consistently you work, the more efficient you'll become just by that practice. The difference lies in the speed at which you can improve. IF you want to improve fast, then it requires training more often (like exercising for bigger muscles), and studying art. Otherwise, it's perfectly alright to just keep drawing, mindful of any improvements you can make through review and moving on to complete the next thing.
Combine that with eliminating distracting and time-wasting actions (those little 1-2 second things you do inbetween working adds up in the hours, days and weeks) and you're on a steady path to improve.
When I first started out with Ch 1, I was cranking out 4 pages every 3 weeks(I'd only post one page- the other 3 would go towards my buffer); by the time I hit Ch 2, the arm/wrist/hand pains had started, so my productivity slowed down. Currently moving slow af right now; if it werent for these issues, I'd still be cranking out pages.
Stage wise, it takes me hours to pencil a page- if I have to plan out backgrounds, even longer. I LOVE inking, so I can whip through inks pretty quick; even if it takes a little longer than my norm I dont mind coz I really like doing it...coloring goes both ways- it starts out being a pain with me having to lay down the flats, but then becomes fun once I get past the flats.