Automatic Gratuity Calculator: Mandatory Tip Added to a Bill
Work out the automatic gratuity added to a restaurant bill and the total with the mandatory tip — the service charge many restaurants apply to large parties, banquets, and events.
Adjust the inputs and select Calculate for a full breakdown.
Compare Common Scenarios
How the numbers shift across typical situations for this calculator:
| Scenario | Automatic gratuity | Total with gratuity |
|---|---|---|
| 18% of $300 ($54) | $54.00 | $354.00 |
| 20% of $500 (event) | $100.00 | $600.00 |
| 18% of $180 (large party) | $32.40 | $212.40 |
| 15% of $250 | $37.50 | $287.50 |
How This Calculator Works
Enter the bill amount and the automatic gratuity percentage. The calculator returns the gratuity in dollars and the total including it. Automatic gratuities are typically added to large parties (often 6 or 8+ guests), banquets, and private events, and they're stated on the menu or booking terms.
The Formula
Percentage Add-On
Rate is the tax or tip percentage applied to the amount
Worked Example
An 18% automatic gratuity on a $300 bill is $54, for a $354 total. Restaurants add automatic gratuities to large parties because big tables tie up servers and historically saw inconsistent tipping. Two things to check: whether the gratuity is calculated on the pre-tax or post-tax total (pre-tax is standard and fairer), and whether it's already included before you add any additional tip — double-tipping on top of an auto-gratuity is a common, costly mistake.
Key Insight
Automatic gratuities sit in a gray zone between a tip and a service charge, with real implications. Legally and tax-wise, a mandatory auto-gratuity is often treated as a service charge (the restaurant's revenue) rather than a tip, which can affect how it's distributed to staff and how it's taxed — unlike a voluntary tip, it may not go entirely to your server. For diners, the practical rules are: always check the bill for an already-included gratuity before adding more (the line is easy to miss, especially on large-party or event checks), confirm whether it's figured on the pre- or post-tax amount, and know that an auto-gratuity is generally expected to be paid, though you can usually raise concerns about genuinely poor service with management. Adding an extra tip on top is optional and appropriate only for exceptional service. The calculator shows exactly what the percentage adds so you can verify the bill and avoid accidentally tipping twice.
Frequently Asked Questions
How is automatic gratuity calculated?
Multiply the bill by the gratuity percentage and add it. An 18% auto-gratuity on a $300 bill is $54, for a $354 total. It's typically figured on the pre-tax food and drink total.
When do restaurants add automatic gratuity?
Usually for large parties (often 6 or 8+ guests), banquets, catered events, and private functions. The policy is normally stated on the menu or in the booking terms. It exists because large tables occupy servers for long periods and historically saw inconsistent tipping.
Is automatic gratuity the same as a tip?
Not exactly. A mandatory auto-gratuity is often legally treated as a service charge (the restaurant's revenue) rather than a voluntary tip, which can change how it's distributed to staff and how it's taxed. So it may not go entirely to your server the way a discretionary tip would.
Do I tip on top of an automatic gratuity?
Generally no — the auto-gratuity is the tip for that bill. Adding more is optional and appropriate only for exceptional service. The common, costly mistake is not noticing the included gratuity and tipping again on top, effectively tipping twice. Always check the bill before adding anything.
Is it on the pre-tax or post-tax amount?
It varies by establishment, though pre-tax is standard and generally considered fairer (you're tipping on the service, not the tax). Check your bill — a gratuity figured on the post-tax total is slightly higher. This calculator applies the percentage to whatever bill amount you enter.
Related Calculators
Methodology & Review
The gratuity is the percentage applied to the bill amount; the total is the bill plus the gratuity. It models a percentage automatic gratuity on the pre-tax bill and does not address whether the gratuity is applied before or after tax, which varies by establishment.
Written by Ugo Candido · Last updated May 22, 2026.