Runway length is a relative thing like what next says. I’ve done some with 400m and 350m in a C182 and that is not a big problem. However, I’ve also done 500m in a TB10 and that was very scary and very difficult. The TB needs enormous amounts of runway.
I am not overly impressed by the above stories. My shortest runway was less than 100m in a C152.
Well, allright, it was actually while landing. And it was a grass field. And, OK, the comment by the airport manager was “Hey Aart, welcome!
Maybe next time land on the runway, just about 50 m to your left!” Rather high grass, could not see the wheels any more, and had a bit of a hard time taxying.. Anyhow, that can happen on your first few hours after you get your license. Bought the airport manager lunch in exchange for complete silence. “Deal” he said 
Well, if we are going to talk about the minimum proportion of runway used, I will offer my CPL Skills Test in a C172 at Stansted (ah…those were the days!)
I was instructed to do a short field landing, to touch down at one taxiway and be stopped before the next.
It was quite a windy day, and I touched down at the leading edge of the taxiway and was stopped well before the further edge. About 10m out of 3050m, so 0.3% of the total.
Any takers? 
My personal shortest take off is from Danish farm strip in North Sealand – 210m of not-too-short grass with full fuel and 2 POB. To help, it was in a KZ VII Lark and my co-pilot had operated the plane out of the strip for years. Less of an issue than I had thought
About 10m out of 3050m, so 0.3% of the total.
What a waste of landing fees When I pay for 3050m of runway I use 3050m…
But I can offer less than that: On my helicopter trial lesson!
The TB needs enormous amounts of runway.
Not compared to other hi-perf IFR aircraft with a Vs just below 60kt.
Helgoland before the runway was extended. If memory serves me right it was 410m
Yes, I agree that everything is relative.
ENHA, Hamar Stafsberg in Norway, home of the upside-down Viking ship that hosted the figure skating competitions in the 1994 Winter Olympics. 800 m runway sloping down quite a bit towards the end of runway 15. Towards the end of winter when the snow accumulated throughout the winter has melted somewhat and then iced up. Aircraft: Mooney M20C then belonging to Hamar Flyklubb.
Only time I have ever came close to a runway excursion.
Sometimes after having landed at Hamar during the winter, when getting out of the aircraft you would fall over on your face because it was so slippery. On ice you have enough aerodynamic control to taxi without really realizing how slippery it is, unless you have some significant (cross)wind.
Helgoland RWY 03 – 371 mtr. Turned into the apron without backtracking.
Homebase 500 mtr grass.
Cessna 172s
