How to Split a Restaurant Bill by Item (Proportional Tip Method)

The Two Ways to Split a Bill

Equal split divides the total (including tip) by the number of people. Simple, but unfair when people order very different amounts.

Item-based split charges each person for exactly what they ordered, plus a proportional share of the tip. If you ordered more expensive items, you pay a larger share of the tip — because the tip is typically based on the full table subtotal.

The Proportional Tip Formula

subtotal = sum of all item prices
tipAmount = subtotal × tipPercent / 100
grandTotal = subtotal + tipAmount

diner's tipShare = (dinerSubtotal / subtotal) × tipAmount
diner's total = dinerSubtotal + diner's tipShare

This approach ensures the tip is distributed in proportion to each person’s order, rather than split equally among diners.

Worked Example

Three items ordered at a table:

• Item 1: $30.00 (Diner 1)
• Item 2: $20.00 (Diner 1)
• Item 3: $15.00 (Diner 2)

Tip: 18%

Step 1: Calculate subtotal and tip

• Subtotal: $30 + $20 + $15 = $65.00
• Tip (18%): $65 × 0.18 = $11.70
• Grand total: $65 + $11.70 = $76.70

Step 2: Per-diner subtotals

• Diner 1: $30 + $20 = $50.00
• Diner 2: $15.00

Step 3: Proportional tip shares

• Diner 1 tip share: ($50 / $65) × $11.70 = 0.769 × $11.70 = $9.00
• Diner 2 tip share: ($15 / $65) × $11.70 = 0.231 × $11.70 = $2.70

Step 4: Totals owed

• Diner 1: $50.00 + $9.00 = $59.00
• Diner 2: $15.00 + $2.70 = $17.70

Check: $59.00 + $17.70 = $76.70 ✓

Why Proportional Tips Are Fairer

An equal tip split would give each person the same tip amount: $11.70 / 2 = $5.85. But Diner 1 ordered more than three times as much food as Diner 2. The proportional split correctly charges Diner 1 a larger share of the tip because their larger order was what drove the total — and the tip is conventionally a percentage of the total.

Common Scenarios

Shared appetizers and bottles. If an appetizer or bottle of wine was shared equally, enter it as a separate item and assign it to each diner in proportion, or split the cost manually before entering individual items.

Tax and other fees. Restaurant bills also include sales tax and sometimes a service charge. If you need to split tax proportionally, the same formula applies: replace tipPercent with an effective combined rate (tip + tax rate) and the math works out identically.

One person pays and collects. Use the calculator to determine exactly what each person owes, then share the breakdown. The person who paid the full bill collects the individual amounts.