账单分摊，免费

工作原理

输入账单小计、税和小费（金额或百分比）。添加分摊人员的姓名。计算器会自动按比例分摊税和小费，并显示每人的金额。

功能特性

• 平均或自定义分摊· 平均分摊，或将具体项目分配给特定人员
• 灵活的小费· 输入金额或使用预设百分比
• 自动计算· 在所有参与者之间按比例分摊税和小费

常见问题

税和小费是如何分配的？

税和小费会在所有参与分摊的人之间平均分配。每人的份额是用总额除以人数得到。

小费可以用百分比或固定金额吗？

可以！小费可以输入小计的百分比或固定金额。使用预设按钮（15%、18%、20%、25%）可快速选择。

我的数据会被保存吗？

不会。所有计算都在您的浏览器中进行。不会发送到服务器，也不会保存。

A short history of splitting the bill

Sharing food costs is as old as eating in groups, Greek syssitia, Roman convivia, medieval guild dinners, tavern gatherings all involved some version of cost-sharing, often with the host absorbing the bill as a status display. The expression "going Dutch" (each person pays their own share) surfaces in English in the late 19th century; the OED's earliest citation is 1873. Anthropologist David Graeber argued in Debt: The First 5,000 Years that immediate exact reciprocation ("I owe you exactly $14.27") is historically unusual even among friends, and that the precision-splitting now made trivial by smartphones marks a behavioural shift, not just a technological one.

Two near-simultaneous launches turned bill splitting from arithmetic into infrastructure. Venmo was founded in 2009 by Andrew Kortina and Iqram Magdon-Ismail (originally as an SMS-based way for one cofounder to pay back a friend who had covered him at a bar). PayPal acquired Venmo in 2013, and by the mid-2010s "Venmo me" had become a verb in American English. Splitwise was founded by Anand Sharma at Y Combinator in 2011 specifically to track group expenses across roommates, trips and households without forcing settlement after every transaction; its IOU ledger model (balances accumulate and only periodically settle) made it the dominant tool for shared housing and travel. Other arrivals followed: Cash App (2013), Apple Cash (2017), Zelle (2017), Tricount (Belgium, 2010, acquired by Bunq 2022), Settle Up (Czech Republic, 2010), and Wise's multi-currency wallet for international group trips.

The math, in plain language

Even split, simplest case: total = subtotal + tax + tip; each person pays total ÷ N, with a tiny rounding adjustment so the sum equals the bill exactly. Subtotal $80, 9% tax ($7.20), 20% tip ($16), 4 people: total = $103.20, each person = $25.80. Sum check: 4 × $25.80 = $103.20.

Itemised split with shared tax and tip: each person's items are added up, then tax and tip are split proportionally (the bigger eater also covers a bigger slice of tax) or evenly across the table. The proportional method is mathematically cleaner; the equal-tip method is socially common because tipping is often felt as a service charge for the table rather than a function of any one diner's appetite.

The rounding residual. Three people splitting $10.00 evenly = $3.3333… → if everyone pays $3.33, the total is $9.99, one cent short. Standard fixes: round everyone down then add 1¢ to whoever has the largest fractional remainder; or use banker's rounding (IEEE 754 round-half-to-even, common in financial software); or have a designated payer absorb the residual cent. This tool typically uses the third convention, the displayed per-person total is rounded for display, and the actual transfer absorbs the cent.

Tip on subtotal vs tip on subtotal-plus-tax

A surprisingly contentious detail. US convention has historically been to tip on the pre-tax subtotal: tax is a government charge, not service. In practice many POS systems and tip calculators compute tip on the post-tax total, which inflates the tip by the local sales-tax rate. In a 9.5%-tax city like San Francisco, a 20% tip on subtotal is 20% of $80 = $16; a 20% tip on total is 20% of $87.60 = $17.52. Etiquette columnists (Emily Post Institute, Miss Manners) consistently recommend the pre-tax convention but note both are accepted in practice.

Tipping conventions internationally

Tipping is one of the most-asked travel questions and the single biggest variable in cross-border bill splitting:

• United States and Canada: the global outlier. Federal tipped-minimum-wage law (FLSA) allows employers to pay tipped workers as little as $2.13/hour in cash wages, with tips expected to bring earnings to minimum wage. As a result, US tipping is part of compensation, not a thank-you. Standard rates: 15% (now considered low), 18% (sit-down minimum), 20% (modern social default), 25%+ for excellent service or large parties. Auto-gratuity of 18–20% is commonly added for parties of 6 or 8+.
• United Kingdom: service charge of around 12.5% is often included on the bill at sit-down restaurants; if not, 10–15% is typical. Pubs and casual cafés don't expect tips. The UK's Allocation of Tips Act 2023 requires service charges to flow to staff.
• Continental Europe: service is typically included by law (Italian servizio coperto, French service compris); diners round up to the nearest euro or leave 5–10% for excellent service. France's 1985 Loi 85-77 made service charges part of the menu price.
• Japan: tipping is not customary and can be felt as insulting. The price on the menu is the price you pay.
• Australia and New Zealand: no tipping culture historically; 10% for excellent service is increasingly common in upmarket Sydney/Melbourne restaurants but still optional.
• Middle East, South Asia: 10% is common; in some countries (UAE, Saudi Arabia) a service charge is often included.

Tax handling

Tax appears differently depending on jurisdiction:

• US sales tax is added to the subtotal at the register and varies by state, 0% in Oregon, Montana, New Hampshire and Delaware, up to roughly 9.5% in California cities once local additions are included.
• EU and UK VAT is included in the displayed price by law, typically 17–25% depending on country and item category. Restaurant menus show prices already including VAT; the receipt breaks it out.
• Canada GST/HST/QST is added at the register, varying by province, 5% federal GST plus provincial sales tax of 0% to 10%.

For internal splitting purposes the math is the same in every jurisdiction; the difference is whether you start from a "subtotal" you can already see on the menu (EU/UK) or have to back-out tax from a printed total to see what was on the menu (US/Canada).

When to split evenly vs by item

Even split is the social default when everyone ordered roughly comparable amounts, when the group is small enough to absorb minor inequities ("I'll cover the round next time"), or when the meal is a shared social experience and itemised arithmetic feels petty. It's the standard for first dates, work lunches, and dinners with friends.

Itemised split is the right answer when appetites or budgets differ widely, when one diner had a substantially pricier dish, when the group includes a non-drinker among drinkers (a frequent itemising trigger), when work-expense reimbursement requires per-person totals, or when a group has agreed up front to split this way. The sitcom-classic "I had a salad" objection from Friends is the canonical example of when even-splitting feels unfair.

There's a documented behavioural-economics wrinkle: in a 2004 paper in The Economic Journal, Uri Gneezy and colleagues showed that diners order more expensive items when they know the cost will be split equally, because the marginal cost to themselves is reduced. The phenomenon is sometimes called the "menu effect" or "diner's dilemma." Aware groups sometimes pre-commit to itemised splitting precisely to avoid this dynamic.

When you'd reach for a browser tool

• Quick one-meal split: no need to install Splitwise and create an account for a single coffee shop tab.
• Travel groups who don't all use the same payment app, or whose home countries' apps don't talk to each other.
• Cross-currency situations: the math is the same in any currency; do the conversion separately at the mid-market rate.
• Quick sanity check on a server's bill: running the receipt through your own arithmetic catches the occasional addition error.
• Corporate expense reports when you need a per-person total for receipt submission, especially for the IRS Publication 463 50% meals deduction in the US.
• Group travel debriefs: combining accommodation, transport and meals into one cleanly-itemised tally.

More questions

What's the right thing to say when someone proposes an even split and I had less?

Etiquette literature is generally on your side: it's reasonable to politely propose itemising before the bill arrives ("Should we just pay for what we each had?"). Most etiquette columnists draw the line at after the bill has been totalled, by then the social transaction has happened and reopening it usually costs more in awkwardness than the few dollars saved. The cleanest fix is to set expectations early: "Let's each pay our own" or "Should we split evenly?" before ordering.

Why does a 20% tip sometimes turn into 24%?

Modern POS systems often default to tip suggestions calculated on the post-tax total, then express them as percentages, so the displayed "20%" is 20% of (subtotal + tax). On a 9.5%-tax city bill, that's effectively a 21.9% tip on subtotal. Some systems also default to 20/22/25% prompts rather than the older 15/18/20%, which has the same upward-pressure effect. If tipping on subtotal matters to you, do the math yourself: tip = subtotal × your-percent.

Should the rounding cent matter?

Almost never. Reasonable groups absorb a one- or two-cent residual without comment, and the actual transfer (whoever pays the card) carries the rounding error. The mathematical purist's answer is the largest-remainder method, which distributes the residual cents to the diners with the largest fractional remainders, but in practice no one cares.

Does anything get sent to a server?

No. The split is computed by JavaScript in your browser; nothing is uploaded; the page works offline once it's loaded. Useful when you want to sanity-check a bill at a restaurant table without inviting an app to track your dining history.

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