And you thought your wedding was expensive!

Economists have done the math and come back with a staggering figure for the impact of the upcoming royal wedding on the U.K. economy: $50 billion.

That enormous sum can be partially blamed on timing: the big event falls between two long holiday weekends in England. You can snag 11 days off by only taking three days of vacation.

"Invariably that leads to a loss of output," CBS News quoted Philip Shaw, chief economist at Investec, as saying. "So, in terms of the impact on GDP in the economy, we're suggesting that it could knock something like a quarter percent off growth," Shaw added. That quarter percent translates into roughly $50 billion.

Of course, London will also be on the receiving end of an influx of tourism and guests to the city, which CBS reports will bring in more than $80 million.

As reported earlier in the week, money should be the last thing on everyone's minds as London continues to suffer through one of its worst air pollution episodes in some time. According to the Telegraph, nearly 40 areas of Britain exceeded European safety limits for poor air quality on April 22.

"The Department for Environment, Food and Rural Affairs has issued a nationwide smog alert as the country faces the hottest Easter weekend for nearly 30 years," the article says. "Temperatures reached 78F (26C) in the South East yesterday, making it hotter than Lisbon, Madrid and Rome."

Boris Johnson, the mayor of London, has yet to issue a smog alert in advance of the royal wedding — despite pressure from fellow politicians.

"We have the prospect of hundreds of thousands of visitors flocking to central London, to stand around all day in one of the most beautiful but polluted cities in Europe," wrote Green Party London Assembly Member and mayoral candidate Jenny Jones in a letter to the mayor. "The mayor should be making people aware of what they are breathing in and the risks to their health. It is important information for people to know if they suffer from a pre-existing respiratory problem. London is currently experiencing an air pollution episode and this is likely to carry through to the royal wedding."

That's one cost you can't measure in dollars and cents.