The "equal split" is a common default among friends. When four friends go to a bar, order roughly the same amount of moderately priced drinks, and ask the bartender to split the check four ways, it is simple and fair enough. Few people mind if Friend A's IPA was $8 and Friend B's vodka soda was $7. It all washes out in the end.
But the equal split relies on an unspoken understanding: Everyone spends in roughly the same range.
When one friend decides they are in a celebratory mood and starts ordering $25 premium scotch, or insisting the table try the $100 bottle of reserve wine, that understanding breaks down. If the final bill is $300, and $150 of that was consumed by a single person, splitting the check evenly forces the frugal drinkers to subsidize the premium drinker's luxury.
Here is how to handle the "Top-Shelf Drinker" at your table.
If You're the One Ordering Top-Shelf
If you are the person ordering the expensive liquor, it's courteous to speak up first so your friends aren't paying for your tastes.
If you order a drink that costs significantly more than the baseline of the table (e.g., a $30 cocktail while everyone else is drinking $6 beers), say up front that you'll cover the difference.
What you could say: "Hey guys, I'm going to get this fancy scotch, so I'm going to put it on a separate tab," or, "Let's just split the food evenly, and I'll throw in an extra $50 to cover my drinks."
By volunteering to absorb your own premium costs, you remove the anxiety from the rest of the table. They can enjoy your company without secretly calculating how much your drink is costing them.
If You're Sticking to Beer
What if the Top-Shelf Drinker lacks self-awareness? What if the $300 bill arrives, they toss their credit card in the middle, and casually say, "Let's just split it four ways, right?"
This is an awkward moment. It helps to speak up right away and to keep it about the numbers, not about the person. Don't criticize their drinking habits; point to the receipt.
For example: "Actually, since you guys got those premium scotches and I stuck to beer, it's probably easier if we just itemize this one. I think my beers and burger came to about $35, so I'll put in about $45 to cover my tax and tip."
By stating what you consumed and rounding your tip up slightly, you come across as fair while still declining to subsidize their liquor.
Opening Separate Tabs Up Front
The easiest way to avoid a dispute over a bar tab is not to share a tab in the first place.
If you know you are going out with a friend who is notorious for ordering expensive rounds, ask for your own tab at the very first interaction with the bartender or server.
When the waiter asks for your drink orders, say clearly: "I'll have a draft beer, and I'll just keep a separate tab on this card, please."
Whether a bar will open separate tabs depends on the bar, so ask at the start. A separate tab keeps your tab apart from the Top-Shelf Drinker's final bill.
Splitting an Itemized Bill Afterward
If the bar refuses to split checks, or the bill arrives as one long piece of paper, don't try to do the math in your head after a few drinks.
One person puts down their card to pay the bartender. Take a photo of the itemized receipt. The next morning, go through it line by line and assign each item to the person who ordered it, instead of splitting the $300 bill equally. Tax and tip can then be divided in proportion to each person's subtotal. A spreadsheet or a bill-splitting app can do this arithmetic for you. The Top-Shelf Drinker pays for their luxury, and the beer drinkers pay for their beers.