how long do i preheat an oven?

You will need to learn how long your oven takes to get up to power.

My old oven takes 15 minutes to get up to 180C.

The light will go off when it gets to the right temperature.

You preheat until the oven reaches the temperature its supposed to be at. Some newer ovens beep when they reach the set temp. If you don't know how to read your ovens you can get an oven thermometer at a reastuarant supply store and place it in the oven while preheating. After about 15 minutes check the temp manually, Remember if the recipe says preheat to 350, then thats the temp the oven should be at before putting your dish in.

The hotter the oven needs to be according to the recipe, the longer it takes to preheat. For an average temperature of 350 degrees, it should take between 10-20 minutes, depending on your oven. For higher temperatures, it can take up to 30 minutes, sometimes longer. If you have an older stove, the only way to tell is with an oven thermometer.

Until the stove registers the desired temperature.

Mine beeps when it gets to the temp.

If things are taking longer the over thermometer might be inaccurate.

The chef said 10 minutes???

Of course it depends on the oven and the temp.

It may take 5 to get to 325 or 10 to get to 450.

Oven temps vary. Sometimes if the bottom of the oven is covered from spills, that affects the cooking.

Some modern ovens let you know when the oven reaches temp, if your doesn't, look in the supermarket, they usually have these little thermometers that go in the oven and give an accurate reading.

On some ovens theres a little light that goes off when its heated to the right temperature, but if not I would say about 5-10 mins or you can just turn it on as you begin preparing, depends on how long your going to take I guess.

Hope I helped !

15-20 min is usually good.

Ovens made in the last 10 years or so usually beep when they have reached the desired temp.

10 minutes

buy an oven thermometer and when it shows desired heat then it is at the correct level

Just turn it on before you start making everything. It will be just right after that.