Buffet Time Calculator
Buffet discard times from serving hour with hot and cold hold rules.
What it does
Buffet clocks run on air temp: two hours at room temp, one hour past 90 F, with hot holding at 140 F and cold at 40 F buying unlimited safe time. Bacteria double near every 20 minutes inside the zone.
The tool above takes serving date and time with air temp. It returns the discard-by stamp with the rule and hold options.
The default 18:00 serving at 72 F discards at 20:00 UTC. A 95 F picnic at noon discards at 13:00.
Rules follow Foodsafety.gov steps with FDA buffet pages behind them. Both agree on 2 hours, 140, 40, and 165 used here.
How to use
- Enter the serving date.
- Enter the serving time.
- Enter the air temperature.
- Read discard-by first.
- Read the rule beside it.
- Hold or chill to beat the clock.
Formula
- serve
- Plating date and time.
- temp
- Air temp in F, 90 splits rules.
- 2 / 1
- Safe window in hours.
- 140 / 40
- Hot hold floor, cold ceiling.
Date math runs UTC across midnight and month ends. The temp input is air temp, not food temp; held foods with thermometer proof sit outside the clock. Cool leftovers in shallow pans within 2 hours.
Worked example
Example: indoor buffet at 6 PM
Defaults: served Oct 10 18:00 at 72 F.
- Serving: Oct 10 2026 at 18:00 UTC.
- Air: 72 F, under 90, so 2-hour rule.
- Discard: 18:00 + 2 hr = 20:00 UTC.
- Stamp: Sat Oct 10 2026, 20:00 UTC.
- Hold option: 140 F+ hot or 40 F- cold.
- Tool shows Sat Oct 10 2026, 20:00 UTC, 2-hour rule.
Reference table
| Rule | Figure | Note |
|---|---|---|
| Room temp limit | 2 hr | Prep counts too |
| Over 90 F limit | 1 hr | Picnics, hot cars |
| Hot hold | 140 F+ | Checked gear only |
| Cold hold | 40 F- | Ice nests |
| Reheat once | 165 F | Sauces to boil |
Limits
- Perishables only; whole fruit differs.
- Thermometer proof beats clocks.
- Transport counts in the window.
- At-risk groups need stricter lines.
Common mistakes
- Topping fresh onto old trays.
- Trusting lukewarm warmers.
- Counting from first bite, not plating.
- Reheating twice.
- Thawing on counters.
Try it yourself
Quick checks. Answers sit tucked under each question.
Noon serving at 95 F?
95 past 90: 1-hour rule, discard Sat Oct 10 2026, 13:00 UTC.
09:30 serving at 68 F?
2-hour rule: discard Sat Oct 10 2026, 11:30 UTC.
Guests arrive at 19:00?
Still 20:00 UTC: the clock starts at plating, not tasting.
Questions
How long can buffet food sit out?
Two hours at room temp; one hour past 90 F. The clock covers prep, transport, and serving.
How hot must hot holding run?
140 F or warmer with checked equipment. Lukewarm 110 to 120 F warmers fail.
How cold must cold holding run?
40 F or colder nested in ice with small trays swapped often, never topped up.
How hot to reheat leftovers?
165 F once through the thickest part, sauces to a rolling boil.
Is anything exempt?
Yes: whole fruit, bread, cookies, and uncut veg with skin run lower risk than cut produce.
Can food thaw on the counter?
No: fridge, cold water, or microwave only. Counters never qualify.