The middle is still cold or frozen after the full time

Safety issue

A cold or frozen centre usually means the timer started before the oven was hot, or a different setting, tray or load. For packaged pizza, a safety issue.

Applies to: frozen pizza, chilled supermarket pizza, take-and-bake pizza, leftover pizza, takeaway or delivery pizza

Safety: Many frozen and take-and-bake pizzas are not ready-to-eat: the base and toppings must be cooked through, not just warmed, even if they look cooked. Follow the pack instructions for the appliances it names, and keep cooking until the centre is steaming hot throughout. Reheat leftovers until steaming hot throughout, and only once.

Ask yourself

Did the timer start once the oven or appliance had fully reached temperature, or when the pizza went in?
Is the oven, setting and position the ones the pack describes — fan or conventional, on the shelf or on a tray?
Was all the packaging removed, including any card disc or film underneath?
Did you add extra cheese or toppings, or cook more than one pizza at once?
If reheating, was it in a microwave, and did the edges get hot while the middle stayed cool?

Likely causes

#1
The oven or appliance was not fully up to temperature when the timer started
Generally accepted
Pack times assume the oven has finished preheating. A pizza that goes into a still-heating oven spends the first part of its time warming up rather than cooking, and the centre — the furthest point from every hot surface — is what runs out of time.
#2
A setting, appliance or surface different from what the pack's times were written for
Generally accepted
Instructions are written for particular appliances and settings. A conventional setting where the pack assumes fan, a tray where it says directly on the shelf, or an air fryer or microwave the pack does not list can all leave the centre behind the stated time.
#3
Packaging left underneath, or extra cold toppings added on top
Generally accepted
A card disc or film under the pizza insulates the base from the heat, and a layer of extra fridge-cold cheese or toppings both insulates and adds cold mass to the centre the pack's time never allowed for.
#4
More than one pizza in the oven at once
Generally accepted
Two pizzas take more heat out of the oven than one, and one usually sits on a shelf shaded by the other, so at least one runs behind the pack's single-pizza time.
#5
Uneven microwave heating when reheating
Generally accepted
Microwaves heat unevenly and leave cold spots, often in the middle of a dense or thick piece; the edges can be very hot while the centre is still cold.

Equipment-specific causes

The same symptom has different answers on different equipment. Each branch below states how to tell whether it is yours.

Equipment

Pizza in an air fryerStrongly supported
How you would know: A frozen or take-and-bake pizza went in the air fryer, the outside looks done or dark, and the middle is still cold — and the pack gives no air-fryer instructions.
The pack's times were written for the appliances it names. In a small, fast air fryer the outside browns quickly and looks finished well before heat has reached the middle of a frozen pizza, so judging by colour leaves the centre behind.
Do now: Lower the temperature and keep cooking until the middle is steaming hot throughout, or finish it in a preheated oven following the pack; see the food-safety note on this symptom.
Change next time: Use the air fryer only for pizzas whose pack gives air-fryer instructions, follow them, and check the middle with a food thermometer rather than by colour.
Pizza on a baking trayGenerally accepted
How you would know: The pack said to bake directly on the oven shelf, but the pizza went on a cold baking tray, and its base is pale as well as the centre cold.
A cold tray absorbs heat from the base at the start of the bake and shields it from the oven's bottom heat, so a pizza timed for the bare shelf finishes its time with the middle still cold.
Do now: Slide the pizza off the tray directly onto the oven shelf and continue until the centre is steaming hot throughout.
Change next time: Follow the pack: if it says directly on the shelf, put it on the shelf (a tray on the shelf below can catch drips); if it says a tray, preheat the tray with the oven.

Bake environment

Pizza in a domestic ovenGenerally accepted
How you would know: The pizza went in as soon as the oven was switched on or when the preheat light first went off, or on a conventional setting where the pack gives a fan temperature.
Pack times assume a fully preheated oven at the stated setting. A domestic oven's air reaches temperature before its walls and shelves do, and conventional (no-fan) settings heat food more slowly than fan settings at the same number, so the centre runs behind the stated time.
Do now: Return it to the oven at the pack's setting and keep going in short stretches until the centre is steaming hot throughout, covering dark edges loosely with foil.
Change next time: Let the oven run for several minutes beyond the preheat light, start the timer only then, and use the setting the pack's temperature refers to (fan or conventional); check from the earliest time given and go on until the centre is hot.

Rescue it now

Put it back in the fully preheated oven, on the shelf or surface the pack names, and keep going in short stretches until the middle is steaming hot throughout; cover any edges that are already dark loosely with foil. A food thermometer pushed into the centre is a more reliable check than colour on top — see the food-safety note

Prevent it next time

Follow the pack's appliance, setting and shelf position, wait until the oven has finished preheating before starting the timer, remove every piece of packaging, cook one pizza at a time, and add extra toppings sparingly and not straight from the fridge. When reheating in a microwave, follow its standing time and check the middle before eating

Domestic fan (convection) oven Domestic conventional (non-fan) oven

Go deeper

Guides that treat this as an outcome to improve, an environment to work with, or a flavour to understand, rather than only a problem to fix.

Pizza in a domestic oven Pizza on a baking tray Pizza in an air fryer