Your wedding day is approaching, and you’ve budgeted for the dress, venue, music, invites and photographer. But there are plenty of hidden wedding expenses that can pop up as late as the big day. We spoke with wedding experts who exposed those tricky little costs, so you’ll have a beautiful walk down the aisle without financial fears tying you down.

TIPPING

Why it’s hidden: You paid for your vendors months in advance, but nothing in the fine print told you about a tip. While a tip isn’t mandatory, it’s expected for good service, said Alison Phillips, president of Engaging Events by Ali.

The cost: If your wedding planner did a great job, you could tip 10 to 20 percent of the fee, or up to $500 at the end of the wedding. You could also tip your wedding ceremony officiant up to $100 if he went above and beyond.

OVERTIME

Why it’s hidden: Many couples decide to extend the wedding, but they’ll incur overtime charges from everyone working on the wedding: the venue, the music, the photographer, video, bar, transportation and more, said Cristina Verger, of Cristina Verger Event Planning & Production in New York.

The cost: It could be thousands of dollars for just 30 minutes or an hour of overtime. “This is a very important item that should be well thought out on the onset of the planning,” Verger said.

FANCY HARD LIQUOR

Why it’s hidden: You paid for a hard liquor package, or perhaps you decided to pay per consumption. But if the more-expensive alcohol is on display, your guests could choose a drink you didn’t plan for. ”

The cost: Depending on how many people are ordering that top-shelf liquor beyond your package, it could be thousands.

POSTAGE

Why it’s hidden: There are entire magazine spreads dedicated to invitation designs and save-the-dates. And let’s not forget about your thank-you notes. But did you consider postage?

The cost: The price of a first class letter just went up from 47 cents to 49 cents. Multiply that by the number of guests you have and the number of announcements and letters you plan on sending them, and this cost could add up quickly.

TAXES

Why it’s hidden: Typically, you calculate the numbers for the big ticket items like the venue, caterer, dress, photographer and music. and you’re golden. But most people forget about the taxes, which can be a significant portion of the bill, depending on where you live, said Anja Winikka, director of education and industry for The Knot.

The cost: Tax and gratuity can add upward of 30 percent, which will throw many couples over budget, Winikka said.

DRESS ALTERATION

Why it’s hidden: You’ve budgeted for the gown, but you probably didn’t realize the hidden cost of the alterations, which is significantly higher than altering a regular dress, McLamb said.

The cost: Between $300 and $500.