Returning Earlier or Later Than Booked at Stansted
Coming back off schedule is normal and nearly always fine. The exceptions are worth knowing before you travel.

Airport Guides

The names describe how they are priced, not how far away they are. Short stay is priced by the hour and sits beside the terminal; long stay is priced by the day and sits a short transfer away.
Book the wrong one and the mistake is expensive in a particular way: short stay for a fortnight costs several times what it should, and nobody notices until the invoice.
Hours, not days.
It exists for drop-offs, pick-ups, meetings and the occasional overnight. The car parks sit directly beside the terminal, so the walk is a few minutes and there is no bus.
That convenience is what you are paying for, and the pricing assumes you will not be there long. For a day trip or a single night it is often the sensible choice.
Short stay is cheap for three hours and ruinous for three weeks. The difference is not distance, it is the meter.
Days and weeks.
It is the official on-airport option for holidays and longer trips. The car parks sit within the airport boundary but far enough out to need a transfer bus, and the daily rate drops sharply compared with short stay.
For most trips of three nights or more, long stay at Stansted is the baseline everything else should be compared against.
A few hours — short stay, by a distance
One night — short stay or long stay, usually close
Two to five nights — long stay, with off-airport worth checking
A week or more — long stay or park and ride, with park and ride usually ahead
Three weeks — park and ride, clearly
The crossover point is around three nights. Below it, pay for the shorter walk; above it, the daily rate starts doing real work.
It changes how much the difference matters, not which option wins.
On a budget fare the parking can be a larger line than the flight. That makes the gap between short stay and long stay proportionally much more significant at Stansted than at a long-haul airport.
The practical effect is that getting this right is worth more here. A fortnight booked into the wrong category can cost more than the holiday flights for a family of four.
Below long stay on price, above it on effort.
Off-airport sites sit a few miles out on cheaper land, which is why the daily rate is lower. The trade is a longer transfer — ten to twenty minutes rather than a few — and a bus that runs less often overnight.
Stansted travellers are more likely than most to be flying with cabin bags only, which is exactly the condition that makes off-airport parking an easy decision.
No, and the single terminal keeps it short.
You are walking to a bus stop within the car park, and the bus does the rest — usually under ten minutes door to door. There is no terminal to confirm and no inter-terminal transfer to allow for.
What varies is frequency, particularly in the small hours. Before about five in the morning, check what actually runs rather than the daytime figure.
It is a different thing entirely, not a third car park.
With meet and greet you stop at the terminal, hand over the keys and walk in. The car is driven to a compound off-airport by the operator.
It buys you the short-stay walk at something closer to a long-stay price on short trips, which is why it is worth pricing on an overnight or a weekend even if you would not consider it for a fortnight.
Work from the length of the trip, then check the time of day.
Under three nights, short stay or meet and greet. Three nights to a week, long stay. Beyond a week, compare long stay against park and ride and expect the latter to win.
Then adjust for an early departure, which at Stansted is most flights. The comparison prices all of them for your actual dates.
Short stay is priced by the hour and sits beside the terminal. Long stay is priced by the day and needs a short transfer.
Only for a day trip or a single night. Beyond that the hourly pricing makes it far more expensive.
Usually under ten minutes door to door, though frequency drops in the small hours.
No, which removes the terminal confusion that complicates parking at Heathrow and Manchester.
Generally from about a week upwards, when the lower daily rate outweighs the longer transfer.
Less often than people assume, because Stansted charges for the terminal drop-off.
That charge applies at both ends if somebody is taking you and collecting you, and on top of it there is the fuel for two round trips by whoever is driving.
There is a free drop-off area further out with a short shuttle, which is the sensible compromise. But for anything beyond a couple of nights, parking is usually both cheaper and simpler than being dropped off twice.