Hi, I’m Muhammad Sami. I build the calculator tools on ApplianceConversion.com, and this page explains where my numbers come from, how I work them out, and why I always tell you the result is a starting point rather than an exact answer.
I want you to be able to trust the tools on this site. The best way I know to earn that trust is to be open about my method, so here it is, in plain words.
Who builds these tools
I’m a software developer, not a professional chef. What I do is take cooking information that already exists in trusted, published sources, turn it into a clear formula, and build a calculator around it. My job is to make that information easy to use and honest about its limits.
That also means I don’t invent cooking times. Every tool on this site is based on numbers I looked up, checked against more than one source, and wrote down so you can see them too.
You can read more about me on my LinkedIn profile, and learn about the site on the About page.
My basic approach
For every tool, I follow the same steps.
First, I research before I write a single line of code. I look up how the conversion is normally done, reading cooking guides, conversion charts, and official food-safety pages.
Then I check more than one source. If two independent sources agree on the same rule, I trust it more. If they disagree, I look for a sensible middle, and I say so.
Next, I turn it into a clear formula. I write the math down in simple terms so the result is consistent every time.
I always show a range, not a single magic number. Cooking is not exact, so a range is more honest than pretending I know the perfect time.
And I tell you the limits. Every result reminds you that conversions are approximate and that you should check your food before serving.
Why conversions are always approximate
This is the most important thing on this page, so I’ll be direct: no conversion tool can give you a perfect cooking time.
Real cooking depends on things a calculator can’t see, like how much food is in the pot, how much liquid you used, the exact size and cut of your meat, and even the brand of your appliance. Two people using the same recipe can get slightly different results.
That’s why every tool gives you a range and tells you to check that your food is properly cooked before you eat it. Think of my numbers as a strong starting point that saves you from guessing, not as a promise.
Food safety comes first
When a conversion involves meat, poultry, or fish, I show the safe internal temperature from the United States Department of Agriculture (USDA). This is the temperature your food needs to reach inside to be safe to eat.
No cooking-time conversion replaces a meat thermometer. The time tells you roughly how long to cook, and the thermometer tells you when it’s actually safe. I always point you to both.
You can see the official safe temperatures here:
- USDA Safe Minimum Internal Temperature Chart, the official US government food-safety reference I use for every protein.
The sources I rely on
Here are the main sources behind the tools on this site. I checked each one and used them to build and double-check my formulas.
For food safety (all tools)
For the Oven ↔ Air Fryer tool
- Inch Calculator, Oven to Air Fryer Conversion Calculator, a clearly sourced guide that follows air fryer cookbook author Linda Larsen’s rule of thumb. I used this as a main reference.
- The Foodie Physician, Easy Oven to Air Fryer Conversion Guide, written by an ER doctor and trained chef, useful for the food-safety angle as well as the conversion rule.
- Everyday Family Cooking, Air Fryer Conversion Chart & Calculator, a second food site I used to cross-check the same rule, including how frozen food is handled differently.
For the Slow Cooker ↔ Instant Pot tool
- Savor + Savvy, Slow Cooker to Instant Pot Conversion Chart, a detailed, food-by-food chart I used as a main reference.
- Gluten Free Supper, Slow Cooker to Instant Pot Conversion Calculator & Cheat Sheet, a second, independent source I used to cross-check the core rule.
For the Slow Cooker ↔ Oven tool
- Just A Pinch, Crock Pot to Oven Conversion, the clearest statement of the core rule I used: divide slow-cooker LOW time by four (or HIGH by two) at a 325°F oven.
- Sur La Table, Slow Cooker vs Dutch Oven Conversion Guide, a second source I used to cross-check the temperatures and timing.
- eHow, How to Convert Slow Cooker Times to Oven Time, the basis for my small per-food adjustments, since it notes that different foods need slightly different conversions (for example, chicken cooks a bit faster).
For the Microwave ↔ Air Fryer tool
- Calculator Cloud, Leftover Reheat Time Calculator, a clear reference for how reheating times relate across appliances, and for the USDA 165°F leftover-safety target.
- From Our Place, Air Fryer Reheating Guide, used for the food-by-food air fryer temperatures (hotter for crispy, lower for delicate items).
- AirFryerJourny, Air Fryer Leftover Reheat Guide, a second source confirming the roughly 3 to 5 times time difference and the list of foods an air fryer is the wrong tool for.
For the Slow Cooker ↔ Pressure Cooker tool
- A Mind “Full” Mom, How to Convert Recipes for a Pressure Cooker, the source for the core rule: slow cooker HIGH hours times six for pressure-cook minutes.
- Food Smart Colorado (Colorado State / University of Idaho Extension), a university extension source confirming the conversion and the liquid and “add vegetables late” guidance.
- Washington Post, The difference between stove-top and electric pressure cookers, the basis for the stovetop (15 psi) versus electric (around 9 to 12 psi) difference, and the reason electric cookers need more time.
For the Oven ↔ Microwave tool
- GE Appliances: Microwave Recipe Conversion. This is the source for the baseline rule that a microwave takes about a quarter of the oven time (a 1-hour oven dish becomes roughly 15 to 20 minutes).
- USDA FSIS: Cooking with Microwave Ovens. A government food-safety source for the facts that microwaves do not brown or crisp, cook unevenly with cold spots, and need a thermometer check in several places.
- Orbit6 and AxisCalc oven-to-microwave calculators. These are the source for the food-category factors and the wattage adjustment (1000 W reference). I treat this as one published category model, not a universal standard.
For the Oven ↔ Pressure Cooker tool
- Blue Jean Chef: Converting Recipes for Pressure Cooking. A source confirming the roughly one-third rule and the kinds of dishes that suit a pressure cooker.
- Miss Vickie: Foods You Should Not Cook in a Pressure Cooker. Used for the wrong-tool list: fried and crispy foods, baked goods, and crust-first roasts do not work under pressure. The stovetop (15 psi) versus electric (around 11 psi) difference is the same one documented for the slow cooker to pressure cooker tool above.
As I add more tools to the site, I’ll add their sources here too, and each tool page will also have a short note explaining the specific math it uses.
A note on the math, in plain words
I try to keep the formulas understandable. Here are the main rules behind the seven tools that are live right now.
Oven to Air Fryer
The widely used rule, which all of my sources agree on, is to lower the oven temperature by about 25°F and cut the cooking time by about 20%. So a dish that bakes at 400°F for 25 minutes becomes roughly 375°F for 20 minutes in the air fryer.
Frozen food is the one big exception. There you usually keep the temperature the same and just cut the time, because the coating needs the full heat to crisp up.
Slow Cooker to Instant Pot
The main rule that both of my sources agree on is that the Instant Pot time in minutes is roughly the slow cooker time on HIGH multiplied by six. So about 4 hours on HIGH (or 8 hours on LOW) works out to around 24 minutes in the Instant Pot.
Slow Cooker to Oven
The rule my sources agree on is to set the oven to 325°F and divide the slow cooker time, by four if it was on LOW, or by two if it was on HIGH. So 8 hours on LOW (or 4 hours on HIGH) becomes about 2 hours in the oven.
On top of that, I apply a small adjustment for a couple of food types: vegetables a bit shorter, and meat a bit longer. The direction of those tweaks follows standard guidance, since sources note that vegetables can cook hotter and faster, while meat does better with longer, gentler heat.
The exact size of the tweak is my own conservative judgment, kept small on purpose. I’d rather be open that this part is my interpretation than pretend it comes straight from a chart.
Microwave to Air Fryer
This one is honestly different from the others, and I think it’s worth explaining why. A microwave and an air fryer don’t share a clean formula, because they don’t really do the same job. A microwave is rated by wattage and heats food from the inside, while an air fryer is set by a temperature and crisps it from the outside.
So instead of pretending there’s a single magic number, I built this tool around the thing people actually want it for: reheating leftovers. The rule my sources agree on is that an air fryer takes roughly three to five times as long as the microwave, at a temperature that depends on the food (hotter for crispy things, lower for delicate or thick ones).
Going back the other way, I divide by the same amount and adjust for your microwave’s wattage, since a 700-watt microwave takes noticeably longer than a 1000-watt one.
And for foods an air fryer simply can’t do, like soups, stews, saucy dishes, rice, and eggs, the tool tells you to use a microwave or stovetop instead of handing you a number that would only lead to a mess.
Slow Cooker to Pressure Cooker
The core rule here is the same one used for the Instant Pot tool: pressure-cook minutes are roughly the slow cooker HIGH hours multiplied by six, so 4 hours on HIGH (or 8 on LOW) comes out around 24 minutes.
What makes this tool its own thing is that it accounts for the kind of pressure cooker you have. Stovetop pressure cookers run hotter, about 15 psi, and cook faster, while electric ones like the Instant Pot run lower, around 11 psi, so they need roughly 25% more time for the same result. That stovetop-versus-electric difference is well documented, and you pick which one you’re using.
Like the slow-cooker-to-oven tool, I also nudge the time a little by food type, with meat and beans needing the longest and vegetables the least. The direction of those nudges follows standard guidance, and the exact size is my own conservative call, kept small.
And there’s an honest point baked in: vegetables turn to mush under pressure if you add them at the start, so the tool reminds you to cook the rest first and add them near the end.
Oven to Microwave
The baseline rule my sources agree on is that a microwave takes about a quarter of the oven time, so a dish that bakes for an hour is roughly 15 minutes in the microwave. The exact fraction depends on the food, so I use a small set of factors: reheating and frozen food is fastest (about a sixth of the oven time), vegetables and liquids a fifth, raw meat about 4.5, and general baked dishes a quarter.
On top of that, the result scales with your microwave’s wattage, using 1000 watts as the reference, since a 700-watt microwave takes noticeably longer. Going the other way, I invert the same math, with an honest note that the oven takes much longer but browns and crisps, which a microwave cannot do.
I want to be straightforward about the food factors. The quarter-time baseline and the wattage adjustment are directly from my sources, but the exact per-food fractions come from one published category model, so I treat them as a reasonable guide rather than a universal standard.
This tool also has an honesty feature built in. For foods a microwave physically cannot do well, like anything you want crispy or browned, it tells you to use an oven or air fryer instead of a number, and for foods that are unsafe to microwave, like whole eggs or whole raw poultry, it shows a safety warning. A microwave leaves cold spots, so I lean on the USDA’s advice to check the temperature in several places with a thermometer.
Oven to Pressure Cooker
The baseline rule my sources agree on is that pressure cooking takes about one third of the oven time for the kinds of dishes that translate, so a 90-minute oven braise comes out around 30 minutes under pressure.
Like the slow cooker to pressure cooker tool, I adjust for the kind of cooker you have. Stovetop cookers run at about 15 psi and are the faster reference, while electric ones like the Instant Pot run lower, around 11 psi, so they get roughly 15% more time. I also nudge the time a little by food type, with meat and beans needing the longest and vegetables the least. The direction of those nudges follows standard guidance, and the exact size is my own conservative call.
Going the other way, an oven takes about three times as long, with an honest note that it browns and roasts, which pressure cooking cannot do.
The most important honesty feature here is the wrong-tool flag, because a pressure cooker is a wet, steamy environment that cannot brown, crisp, or bake at all. So for fried and crispy foods, for baked goods like cookies and pastry, and for roasts where the crust or bark is the point, the tool does not give a number. It explains why and points you to an oven or air fryer, and where it helps, it suggests pressure-cooking for tenderness first and then finishing in the oven or under the broiler for color.
And as with every pressure tool, it reminds you about the liquid minimum and the build and release time that sit on top of the cook time.
A couple of things that apply across the tools
Some foods don’t follow these rules exactly, so I adjust for them. For the Instant Pot, rice and vegetables cook much faster, beans take a little longer, and large cuts like a roast are worked out by weight instead. Each tool’s own page explains the version of the math it uses.
I also keep two things separate that are easy to mix up:
- Cook time, the actual cooking time you set.
- Pressure build and release time, the extra few minutes an Instant Pot needs to build up and let off pressure. This is not part of the cook time, so I show it separately instead of hiding it inside the number.
If you spot a mistake
I’d genuinely rather know. If you think a number looks off, or you have a trusted source that says something different, please reach out through the Contact page or my LinkedIn. I update the tools when I find a better answer, and I’d rather get it right than be stubborn.
