Every rate board is the same four numbers
Parking signage is written to look complicated and almost never is. There is a first period with its own charge, an increment that applies afterwards, a charge per increment, and usually a daily maximum. Read those four off the board and the arithmetic is fixed. A garage charging $4 for the first hour and $3 per half hour after it costs $4 for an hour, $16 for three hours, and $55 for nine and a half — except that a $28 daily maximum, if there is one, stops it at $28 and makes the difference between the two readings of the same sign larger than most people's lunch.
The detail that catches people is rounding. Increments always round up, without exception and without a grace minute inside them. In a half-hour garage, 61 minutes and 89 minutes cost exactly the same, and 91 minutes costs more than both. If you are close to a boundary and the increment is expensive, walking back a few minutes early is the highest hourly rate you will earn all day.
Daily maximums and where they reset
A daily maximum changes the shape of the cost entirely: below it, every increment matters; above it, extra hours are free. But maximums are defined differently between operators, and the difference only shows up on longer stays. Some reset at midnight on the calendar, so arriving at 9pm and leaving the following evening crosses two calendar days and is charged two maximums. Others run for 24 hours from the moment you entered, which for the same stay is one. This calculator uses the second convention, counting 24-hour blocks from arrival. If you are leaving a car for several days, that single question is worth asking before you park.
Airports and rail stations are the usual place this bites, and they are also the usual place where a separate long-stay lot exists at a fraction of the rate of the one nearest the terminal. Shopping centres and restaurants often run validation instead: a period of free time granted against a receipt, usually needing to be registered at a desk or scanned at the machine before you pay rather than argued about afterwards.
When a monthly pass pays for itself
The break-even is a single division: the pass price divided by the cost of one typical day. A $250 pass against $28 days pays for itself at nine days a month, which anyone commuting even part-time will exceed. The calculation gets more interesting when your pattern is irregular — hybrid schedules, travel weeks, months with holidays — because a pass charges the same whether you use it twice or twenty times.
Worth checking before you commit: whether the operator sells a cheaper weekday-only or daytime-only pass, whether the pass guarantees a space or merely a rate, whether it covers evenings and weekends, and what happens if you cancel mid-month. A pass that does not guarantee a space during an event is worth noticeably less than one that does.
What this page will not tell you
It does not know any garage's rates. Everything above came out of the fields you filled in, and operators set their own pricing, change it for events and weekends, run promotions, and apply validation rules that differ between the tenants of the same building. Municipal on-street parking is a separate world again with its own hours, meters, permit zones and enforcement. Read the board where you are standing, put those numbers in, and the arithmetic will be right even though the rates are only ever yours.
Questions people ask
Why did I pay more than the calculator said?
Usually one of four things. The increment rounded up further than you expected, because it rounds on the increment rather than the minute and does so at the moment you exit rather than when you decided to leave. The daily maximum reset at midnight instead of running 24 hours from entry, which turns one long stay into two charged days. Validation was not applied, because most systems require it to be registered or scanned before payment and will not credit it afterwards. Or the rate itself differs by day or event — many garages run a higher flat rate for events and weekends that is not the same board you read on a Tuesday. Check the receipt against the four numbers you entered and the discrepancy is nearly always one of those.
Is it cheaper to leave and come back?
Occasionally, and it is worth a moment's thought when the daily maximum is far above the first-period charge. Two separate three-hour stays each pay a first period, which is often cheaper than one continuous stay of eight hours that has been accumulating increments the whole time. But it is frequently a false economy: you spend the fuel and the time driving in circles, you may lose the space, some garages detect a re-entry within a short window and continue the original ticket, and if the stay would have hit a daily maximum anyway the second entry costs you a whole second maximum. Do the arithmetic for the specific board rather than assuming either way.
How does validation actually work?
A merchant grants a period of free parking against a purchase, and the mechanism varies. Some stamp or scan a paper ticket. Some register your licence plate in a system at the point of sale. Some issue a code you enter at the pay station. The common thread is that it has to happen before you pay and usually before you reach the exit, because once the transaction has completed there is generally no mechanism to reverse it and the person at the gate has no authority to. If you are shopping somewhere that validates, ask at the point of purchase rather than at the exit gate. Validation also frequently caps at a fixed number of hours rather than covering the full stay, so a long visit still pays for the tail of it at the normal rate.
Does the overnight flat rate here match how garages actually charge?
Only when the overnight window falls entirely inside your stay, which is the assumption this page makes and states. Real practice is inconsistent. Some operators apply a flat overnight rate only if you arrive after the window opens and leave before it closes. Some pro-rate a partial overnight period at the hourly rate. Some apply the overnight rate and the daytime rate to their respective portions of a stay that straddles both. Some make the flat rate conditional on arriving after a particular hour regardless of when you leave. If the overnight component is a significant part of what you expect to pay, the calculation here is an approximation and the rate board or the attendant is the authority.