Has this ever been explicitly mentioned in the comic book?
I remember one story in which Spidey thinks: “The Daily Bugle [where Doc Octopus is holding the staff hostage] is about 2 miles away. That’s 3.3 minutes by webline.” Assuming he was going to really put his back in it so this is his maximum speed, that works out to about 36 MPH, not bad for Manhattan traffic.
As an afterthought, Spider-Man’s travel speed is such that he always shows up late for dates with Mary Jane, dinners with Aunt May, funeral services, university exams, and other important social activites, thus prompting someone to walk away in disappointment from Peter Parker in the comic’s last frame, leaving Peter to his “great power/great responsibility” angst while the shadow of Spider-Man looms over him.
“In the chill of night,
At the scene of the crime
Like a streak of light
He arrives just in time”
You can’t reduce poetry to MPH.
Shouldn’t this question be in GQ? 
After all there is no real “super power” to his mode of travel, it’s just a series of pendulum swings right?
How fast does Spider-Man travel webslinging, in MPH?
He travels at the speed of fantasy, which I believe is roughly 20 jillion kabillion MPH!
This may sound crazy, but I once used Excel to create a mathematical model for “swinging from a Bat-rope or web-line”.
The peak swing speed varies, depending on the length of the line and the starting angle, but I recall it getting pretty brisk… 40 mph or more in some cases.
Of course, the average speed will be less than the peak speed, and Spidey’s path can’t be a straight line, so I think it would be very hard for him to quickly calculate travel-time to a given location, unless he had traveled that route before.
If anybody’s really interested, I’ll dig out the spreadsheet and run some more numbers.
The problem isn’t swinging once, that could be pretty quick, (about to terminal velocity depending on your starting point - you’re basically a pendulum) but to extend another web fast enough - without any recoil to slow you down - that would be a trick.
These guys discuss the physics of movies in good detail, they have Spidey too.
Vlad. I can swing both higher and faster if I pull down on the rope on a swing set and extend my legs as I move forward-- really ‘put my back into it,’ to paraphrase Bryan Ekers.
So wouldn’t Spider-Man’s superstrength allow him to achieve much greater additional, um, thrust (I’m don’t think that’s the word) as he pulled himself along the spider-cord that way? The cord has incredible tensile strength and Spider-Man has been known to pull/lift objects in excess of one ton with just one hand, so…
To a limit. Swing fast enough, and the swing will go horizontal. Swing any faster than that, and you’ll keep on looping over, resulting in a decrease in your average speed. From what I’ve seen, Spider-Man’s swings do peak out at horizontal, so he’s already doing the best he can on that score.
dinoboy, he doesn’t need any “recoil to slow him down”, he already has gravity to slow him down. In between webs, he’s momentarily in free-fall. And I think that it’s quite well established that his reflexes are more than fast enough to extend another web in time.
Can anyone tell me how long the webs are that Spidey swings from? I could calculate his speed, but it’ll depend on the web length (longer = faster).
There were some early Ditko stories where he used the webs to slingshot himself across Manhattan; probably about the fastest use of the webs he’s ever used.
I certainly agree with you Chronos, but even if his reflexes are efficient (which I assume they are) they are not as important as the extension of mass (like a web that is both long enough and strong enough) away from him. Unless his web shooters (or whatever) are without recoil (that’s unlikely given the necessary mass of the webs - where does that force go then?).
And the further the web had to shoot, the more mass extended, and the more force exerted upon Spidey. He would be effectively “slowed” every time he “shot” his webs, at least to a limiting speed, no? In either case that is the least of his problems, you can refer to the physics site I posted above for a better diagnosis.
How about the problem of crashing into stuff? If he fires a web to the side of a building, his natural tendency will be to swing into the side of the building below the anchor point.
He’s probably tough enough to take the impact, but a lot of those buildings are glass! Will they handle 80 kilos or so of Spidey smashing into them at 40 mph?
He can get around this somewhat by firing off at an angle to his current motion, so that he’ll tend to swing in an arc, but this adds yet another complication to his already-nightmarish trajectory problem.
Well, we assume his spider-sense (patend pending) lets him do this instinctively.
While his webs are not massless, we already know that they’re extremely light. After all, he carries all the material for them on his own person. Spider-man carrying a full load of web-cartriges (or Spider-man with his web glands full, in the movie version) doesn’t weigh appreciably more than Spider-man “empty”, and that’s enough for what, hundreds? of webs. How the webs can be simultaneously so light and so strong is left as an exercise for the reader.