KitchenCalculators
Free calculators for the questions that come up before a holiday dinner: how big a turkey, how long to thaw and roast it, how long to cook a ham or a prime rib roast, and how to turn an oven recipe into air fryer settings.
- Built from USDA tables
- Every source dated
- Tested against worked examples
- Free, no sign-up
Start with a calculator
Free, instant, nothing is stored.
- Turkey Calculator
- Oven to Air Fryer Converter
- Ham Cooking Time Calculator
- Prime Rib Cooking Time Calculator
Scroll down for the key findings and how each tool is built.
All kitchen calculators
Pick the tool that matches your question. Each page shows its source tables, worked examples, and what we could not confirm.
Key findings
These are numbers from the sources behind the calculators. Each one links to the tool that uses it, and each page names the source and the date we read it.
| Finding | Source | Tool |
|---|---|---|
| USDA says to allow 1 pound of turkey per person, and 1¼ pounds for a frozen pre-stuffed turkey. | USDA FSIS, Let’s Talk Turkey (updated 17 Nov 2023) | Turkey calculator |
| A turkey takes about 24 hours to thaw in the refrigerator for every 4 to 5 pounds. A 12 to 16 pound bird takes 3 to 4 days. | USDA FSIS, Turkey Basics: Safe Thawing (updated 24 Oct 2023) | Turkey calculator |
| Cooking a turkey from frozen takes at least 50 percent longer than a thawed one. | USDA FSIS, Let’s Talk Turkey | Turkey calculator |
| The USDA ham table runs from 10 minutes per pound for a spiral cut to 35 to 40 for a bone-in shank or fresh half ham. | USDA FSIS, Hams and Food Safety (updated 15 Jan 2025) | Ham calculator |
| Cooked hams packaged in a USDA-inspected plant are reheated to 140°F. Others go to 165°F. | USDA FSIS, Hams and Food Safety | Ham calculator |
| Moving an oven recipe to an air fryer means 25 to 50°F lower and about 20 to 25% less time, by two published guides. | Instacart (11 Dec 2025) and UMaine Extension (7 May 2026) | Air fryer converter |
| Instacart’s own potato and cookie examples cut 25 to 40% of the time, more than its stated 20%. | Instacart, our arithmetic | Air fryer converter |
| USDA lists 23 to 30 minutes per pound for a bone-in rib roast at 325°F and 39 to 43 for a 4-pound boneless one. Beef roasts go to 145°F and rest at least 3 minutes. | USDA FSIS, Roasting Those “Other” Holiday Meats (updated 5 Dec 2024) | Prime rib calculator |
To cite a finding, link to the calculator page and name the USDA or other source in the table. The figures are rules of thumb and approximate times. They are not a substitute for a food thermometer.
How these calculators are built
Each calculator starts from a published table or guide: a USDA Food Safety and Inspection Service page, or a named cooking guide. We write the formula down, test it against hand-worked examples, and print the same examples on the page so you can check the arithmetic.
- We read the official source and record the date we read it.
- We write the formula and list every assumption the source does not spell out.
- We test it on worked examples, including edge cases and bad input.
- We say what we did not test in our own kitchen.
- We re-read the sources when they change.
Kitchen calculator questions
Are the results official?
No. They are estimates from published USDA tables and cooking guides. Your oven, your ham or your turkey can behave differently, so use a food thermometer.
Do you store what I enter?
No. Each calculator runs in your browser and sends nothing to a server.
Why do the pages say ‘not tested in our kitchen’?
Because we have not cooked every row in every table. The numbers come from the sources, and the pages say so.
How current are the numbers?
Each page states the date we read its sources. We update them when a source changes.
About the figures
The turkey, ham and prime rib tools use pages from USDA FSIS read on 26 October 2026. The air fryer tool uses an Instacart guide and a University of Maine Cooperative Extension article read the same day. Each tool page lists its own sources and limits. Questions about a figure can be sent through our About page.