The setup
Six friends at a Saturday brunch. Three of them buy the $18-per-person bottomless mimosa deal. The other three drink coffee and water. Everyone orders their own entree. One person (Priya) picks up the whole check.
Why an even split would be unfair
If the group split the final check evenly, each person would pay for one-sixth of the $54 in mimosas — even the three who never touched a drink. That's $9 each. Over dozens of brunches, that pattern is exactly how "we always split evenly" quietly costs the non-drinkers hundreds of dollars a year.
The itemized subtotal
- Alex: eggs benedict $18 + bottomless mimosa $18 = $36
- Blake: pancakes $16 + coffee $4 = $20
- Casey: avocado toast $17 + bottomless mimosa $18 = $35
- Devon: chicken and waffles $19 + coffee $4 = $23
- Eli: shakshuka $17 + bottomless mimosa $18 = $35
- Priya (payer): omelet $16 + water = $16
Subtotal: $165.
Tax and tip
- Sales tax at 8%: $13.20
- Tip at 20% on pre-tax subtotal: $33.00
- No fees
Final bill: $211.20.
Proportional split, everyone's number
Each person pays their subtotal plus a proportional share of tax and tip. Their share of extras = (their subtotal / 165) × $46.20.
- Alex: $36 + ($36/165 × $46.20) = $36 + $10.08 = $46.08
- Blake: $20 + $5.60 = $25.60
- Casey: $35 + $9.80 = $44.80
- Devon: $23 + $6.44 = $29.44
- Eli: $35 + $9.80 = $44.80
- Priya: $16 + $4.48 = $20.48
Sum check: $46.08 + $25.60 + $44.80 + $29.44 + $44.80 + $20.48 = $211.20. ✓
Compare with the even split
Even split would have been $211.20 ÷ 6 = $35.20 each.
- Alex: saves $10.88 by itemizing (they were a mimosa drinker but also had the priciest entree)
- Blake: saves $9.60
- Casey: pays $9.60 more (they had a mimosa and a mid-priced entree)
- Devon: saves $5.76
- Eli: pays $9.60 more
- Priya: saves $14.72 — the biggest saver, and the reason itemizing matters most for the payer
Notice who wins in an even split: the mimosa drinkers with mid-priced entrees. Notice who loses: the non-drinkers, especially the one with the smallest order (Priya).
The right way to bring it up
The move at the table is to name the split method before ordering, not after the check arrives:
"For anyone doing bottomless — let's just each cover what we ordered so the water drinkers aren't buying half our mimosas."
That framing gives the drinkers a chance to agree without feeling called out, and it protects the non-drinkers without making them argue for their own dollars.
For a brunch this shape, BillSplitterApp makes the split trivial — enter each menu item, share the link, each friend claims what they had.