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UseCOS Group Bill Splitter & Tip Calculator calculates equal and itemized bill shares, pre-tax/post-tax tips, and sales tax distribution. It outputs exact per-person owed amounts and creates formatted summary text ready to paste into WhatsApp, iMessage, Venmo, or Interac e-Transfer requests.
Split restaurant bills evenly or by itemized food & drinks. Generates a 1-click WhatsApp/iMessage breakdown with fair proportional tax and tip sharing.
When splitting an itemized restaurant check, the fairest method is proportional allocation: each person pays for their exact food and drinks, plus a percentage of the total tax and tip equal to their share of the food subtotal.
Proportional Share Formula: Person's Total = Item Subtotal + (Item Subtotal / Total Food) × (Tax + Tip)
Selecting between even splits and itemized allocation depends heavily on group size, alcohol orders, and dining fairness dynamics:
| Dining Scenario | Recommended Method | Tax & Tip Allocation Rule | Social & Financial Impact |
|---|---|---|---|
| Uniform Entrees & No Alcohol | Even Split (Total ÷ N) | Equal share of subtotal, tax, and tip. | Fastest checkout; zero friction when meals cost within $5 of each other. |
| Uneven Orders (e.g. Steak vs Salad) | Itemized Proportional Split | Tax & tip scaled to individual entree dollar weight. | Prevents light diners from subsidizing high-ticket entrees. |
| Shared Alcohol & Non-Drinkers | Sub-Group Alcohol Ring-Fence | Alcohol bottle subtotal + tax/tip divided strictly among drinkers. | Essential etiquette rule; non-drinkers never pay for craft cocktails or wine. |
| Large Groups (6+ Diners) | Auto-Gratuity Verification | Examine receipt for 18% service charge before entering custom tip. | Prevents accidental "double tipping" on pre-tax or post-tax totals. |
| Service Level | Tip % (US & Canada) | When to Apply |
|---|---|---|
| Standard / Good | 15% – 18% | Standard sit-down dining with attentive service. |
| Great / Exceptional | 20% – 25% | Large groups, complex drink orders, or stellar service. |
| Large Group Auto-Gratuity | 18% | Many restaurants automatically add 18% for parties of 6+. |
Tipping is a cultural norm, not a legal requirement, so no government body sets these percentages. Benchmarks above are based on the Emily Post Institute's tipping guide (15%-20% for sit-down wait service), cross-checked against common large-party auto-gratuity practice at US and Canadian restaurants. Individual restaurants and regions vary — check your bill for an already-included service charge before tipping again.
Authored by UseCOS Research & Engineering.