Most people split restaurant bills by dividing the total equally. It's simple, it's fast, and for a table of people who all ordered roughly the same amount, it works fine. But when one person had a starter, two glasses of wine, and the most expensive main — and someone else had just a salad and tap water — equal splitting starts to feel unfair.

The same problem applies to tax and tip. If you split everything equally, the person who ordered less ends up subsidising the tip on a steak they didn't eat. Here's how to do it properly, and how to stop doing it manually.

The Two Ways to Split Tax and Tip

Method 1: Equal split (simple but often unfair)

Total the bill including tax and tip, divide by the number of people. Everyone pays the same. This is quick but ignores the fact that people ordered different amounts.

Method 2: Proportional split (fairer for most situations)

Each person pays for what they ordered, plus a proportional share of the tax and tip based on how much of the subtotal they accounted for. If you ordered 60% of the food, you pay 60% of the tax and tip.

This is the method SplitEven uses automatically. It's the method most people intuitively feel is fair — and it's what you'd calculate if you had the time and patience to do the maths.

The Maths Behind Proportional Tax and Tip

Here's a worked example. Four friends at a restaurant:

Person Food ordered % of subtotal
Alex $32.00 40%
Bea $24.00 30%
Carl $16.00 20%
Dana $8.00 10%
Subtotal $80.00 100%

Tax is 8% ($6.40) and tip is 18% ($14.40). Total tax + tip = $20.80.

Proportional tax + tip per person: Alex: 40% × $20.80 = $8.32 → Total: $32.00 + $8.32 = $40.32 Bea: 30% × $20.80 = $6.24 → Total: $24.00 + $6.24 = $30.24 Carl: 20% × $20.80 = $4.16 → Total: $16.00 + $4.16 = $20.16 Dana: 10% × $20.80 = $2.08 → Total: $8.00 + $2.08 = $10.08

Compare that to an equal split: $100.80 ÷ 4 = $25.20 each. Dana, who only ordered $8 of food, would pay $25.20 instead of $10.08. That's a significant difference — and it's why proportional splitting matters when orders vary widely.

Common Mistakes When Splitting Bills with Tax and Tip

⚠️ Forgetting that tax is already included in some countries In most of Europe, Australia, and India, the listed menu price already includes VAT or GST. Adding another percentage for tax is double-counting. In the US, Canada, and some parts of Asia, tax is added on top of the menu price. Check the receipt — the tax line will tell you.
⚠️ Tipping on the post-tax total In the US, the standard convention is to calculate the tip on the pre-tax subtotal, not the total including tax. So for a $80 subtotal with 8% tax ($6.40), tip at 18% would be $80 × 0.18 = $14.40 — not ($80 + $6.40) × 0.18 = $15.55. The difference is small but it adds up over many meals.
⚠️ Missing the mandatory service charge Many restaurants add a service charge automatically — often 10–20% for groups of six or more. This appears as a separate line on the receipt. If you're also adding a voluntary tip on top, you may end up over-tipping significantly. SplitEven reads this from the receipt so it's included automatically.

How SplitEven Handles Tax and Tip

SplitEven reads the tax and tip figures directly from the scanned receipt. It then splits them proportionally across each person based on their food total — automatically, without any manual calculation. The AI detects whether the receipt shows tax separately or already included, and handles service charges and tips as distinct line items.

The result: everyone sees exactly what they owe, broken down by their individual items plus their proportional share of tax and tip. No mental arithmetic, no arguments, no one accidentally paying for someone else's wine.

Split tax and tip automatically — scan any receipt

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When Equal Splitting Is Actually Fine

Not every bill needs the proportional treatment. Equal splitting makes sense when everyone ordered roughly the same amount, when the group is comfortable with a relaxed approach, or when the total difference between proportional and equal would only be a dollar or two. The goal is fairness — and sometimes that just means not making things more complicated than they need to be.

If you're splitting a big group dinner where orders varied a lot, or if you're splitting with someone on a tight budget who ordered much less, proportional is worth the extra effort. SplitEven makes it automatic either way.

Frequently Asked Questions

Should tip be calculated before or after tax?
In the US, the convention is to tip on the pre-tax subtotal, not the post-tax total. On an $80 subtotal with $6.40 tax, an 18% tip is $14.40 — calculated on $80, not on $86.40. The difference is small but it is the standard practice.

Is tax already included in menu prices in Europe and Australia?
Yes. In most of Europe, Australia, and India, listed menu prices already include VAT or GST — there is no separate tax line to split. In the US, Canada, and parts of Asia, tax is added on top and appears as a separate line on the receipt.

What is a service charge and is it different from a tip?
A service charge is a mandatory fee added by the restaurant, often 10–20% for larger groups. Unlike a voluntary tip, it is automatically included in the bill total. If you add a voluntary tip on top of an existing service charge, you may end up significantly over-tipping.

How do you split tax and tip fairly when everyone ordered different amounts?
The fairest method is proportional splitting — each person pays tax and tip in proportion to their individual food subtotal. If someone ordered 40% of the food total, they pay 40% of the tax and tip. SplitEven calculates this automatically from the scanned receipt.

The Short Version

For more on splitting restaurant bills fairly, see our guide to how to split a restaurant bill fairly.