Let me guess: You haven’t been to the museums in Balboa Park yet because you can’t afford admission. Student loans only cover so much, after all.

I’ll just break it to you now: The museums aren’t going to offer daily free admission any time soon. As it turns out, they can’t afford to. Not only that, they’re pretty skeptical about our claim that we can’t afford admission.

The mysterious thing about museums is that some are free and some are not. To delve into the monetary innards of a museum is to comprehend why this is so.

Most museums are nonprofit organizations, but they aren’t cheap to run. You have to pay the docents, keep the floors waxed, run ad campaigns, hire security and maintain the exhibitions.

Just obtaining an exhibition is costly — a particular diamond exhibit cost the San Diego Natural History Museum in Balboa Park millions of dollars.

How do museums pay for all of this? Charging admission is the obvious answer. The Natural History Museum raised admission from $7 to $12 during its diamond exhibit just to break even. But for most museums, admissions revenues only make up 5 to 15 percent of the budget.

If a museum is lucky, it has an endowment, which is basically a fat chunk of money donated by a rich philanthropist. Museums don’t actually spend the endowment. They cash in on the juicy interest collected by the principal. In some cases, that income is enough to permit free attendance — that’s how the Timken Museum of Art in Balboa Park has offered free admission since 1965.

The mother of all endowments belongs to the Getty Center in Los Angeles. It has a roughly $5 billion endowment, with around $3 billion allocated for the museum itself.

Museums also generate income by offering memberships, where members pay an annual fee in exchange for cushy benefits such as free admission and invitations to exhibition previews. Membership fees can be pricey, but at the San Diego Museum of Art, for example, a basic family membership costs $55.

San Diego museums can also apply for money generated by the city’s Transient Occupancy Tax. Visitors to San Diego’s hotels pay the tax, which is redistributed to various arts and culture institutions. The city also helps out by leasing city-owned structures to the museums for as little as $1 per year.

When all of these numbers add up, museums can offer free admission. But most of the time, the numbers don’t add up. Some museums can’t even afford to pay their employees — the staff at the San Diego Natural History Museum recently took a 10 percent pay cut. And when you’re paying for security crews five nights a week and cleaning crews three nights a week, as the San Diego Hall of Champions Sports Museum does, there’s not a lot of money to throw around.

The fact is, most museums would need an enormous endowment before they could offer free admission.

Admission from the Los Angeles County Museum of Art generates between $1 million and $2 million annually. Its membership program, which offers free admission to members, generates another $8 million per year. If the museum offered free admission without a membership, about half of the museum’s current members would probably cancel. So to offer free admission, the museum would need an endowment of $80 million to $100 million.

Actually, many San Diego museums do offer free admission as part of Balboa Park’s Free Tuesday program. Park museums are organized into clusters that offer free admission on a certain Tuesday of the month.

On the fourth Tuesday of every month, for example, the San Diego Hall of Champions Sports Museum offers free admission. And on free admission days, attendance goes up as much as 300 percent.

The San Diego Natural History Museum might get 1,500 to 2,000 visitors on a regular day. On a recent free day, it received about 7,800 visitors.

It’s interesting to note that the museums don’t offer free admission out of a selfless humanistic desire to bring art to the masses. Museums that receive public funding, such as the Transient Occupancy Tax funds, are required to participate.

What’s even more interesting is that even with free admission, we students still don’t show up. Why not?

The United States itself doesn’t have a rosy track record for museum attendance. Only around 8 percent of Americans frequent cultural institutions such as museums, theaters and symphonies.

Another factor could be that San Diego museums haven’t been around long enough to build a following.

Museums in older cities, particularly on the East Coast, are decades older than our own. Further, there are few big-time, dollar-wielding corporations in San Diego to play fairy godmother to our struggling museums.

Financial capitals such as New York City are strewn with corporate headquarters willing to make donations. Similarly, the National Gallery in Washington gets 80 percent of its funding from the government. The best UCSD can do for our free campus art museum is 60 percent.

San Diego’s sunny skies could be a factor in our general citywide apathy for the arts. Indoor diversions in rain-sodden cities such as Seattle are apparently better, cheaper and more plentiful. In San Diego, potential museum patrons spend their free time outside and their spare cash on surf boards and cover charges.

One museum spokesperson flatly rejected the idea that college students don’t go to museums because they can’t afford museum admission fees. She said that admission costs only as much as a couple of beers and guessed that many UCSD students drive nicer cars than she does.

Another idea is that college students don’t frequent museums because they’re only open during the day, when school is in session. In San Diego, museums slam their doors as early as 4 p.m. If only our museums were more like London’s hip Tate Modern, where museum patrons slurp milky tea while statue-gazing late into the night.

As it turns out, Balboa Park museums have tried the late-night idea. In previous summers, some Balboa Park museums stayed open late on Thursday nights. But apparently, nobody wanted to hang out in Balboa Park after nightfall. (And, to get back to their money problem, the museum couldn’t afford to properly advertise the new hours.)

It hasn’t been a hot idea in Los Angeles, either. For the last four years, the Los Angeles County Museum of Art extended its hours from 6 p.m. to 8 p.m. with disappointing results.

It’s difficult to depict San Diego’s museums as money-hungry monsters that exploit their student visitors by charging admission. Since daily free admission for San Diego museums is nowhere in sight, we might as well get used to the idea. Additionally, most museums offer student rates, which is more than we can say about the downtown clubs that charge three times as much to get in the door.