How do I tell when a cake is actually done?

The middle springs back when pressed lightly and leaves no dent. A skewer in the centre comes out with moist crumbs clinging to it rather than wet batter. The edges have pulled very slightly away from the pan wall, and the surface has stopped hissing, which is the sound of water still boiling off. Any one of those beats a clock.

Why is the bake time a range rather than a number?

Because a single number would be false precision. This figure is computed from pan geometry rather than measured, and home ovens commonly run 25 F away from their dial in either direction, which shifts a bake time by more than the whole range. Treat the low end as the moment to start checking and let the doneness test decide the rest.

Should I bake at 325 F or 350 F?

The convention is 350 F for layer pans under a 10 inch span at 2 inches deep, and 325 F once the shortest span reaches 10 inches or the pan is 3 inches deep. Dropping 25 F always costs time and always gives a flatter, paler cake, so it is a trade rather than an improvement. A 9 by 13 bakes at 350 F despite its area, because no part of it is more than 4.5 inches from a wall.

Do bake-even strips change the bake time?

Yes, usually adding a few minutes, and they are worth it anyway. A damp strip around the pan slows the outside so the middle catches up, which stops a dome forming. The cake finishes flat enough to stack without levelling, so the extra minutes buy back the cake you would otherwise cut off the top and throw away.

Batter and baking

Bake Time and Temperature Calculator

A starting bake time computed from pan geometry, with the oven temperature convention and the doneness tests.

Quick answer

An 8 inch round pan filled two thirds starts checking at 25 minutes and usually runs 25 to 40 minutes at 350 F. This is a computed estimate from the pan geometry, not a tested time, and home ovens vary by more than the width of that band, so the doneness test decides.

Pan

Fill level (percent)

Oven temperature (F)

Leave at 0 to use the convention for this pan

Result

25 to 40 minutes

at 350 F, checking from 25 minutes

Every figure, with what it is based on
Figure	Value	Basis
Start checking at	25 minutes	Computed estimate
Oven temperature	350 F The convention for this pan	Trade convention
Batter depth	1.34 in The main driver of bake time	Derived
How you actually tell	The middle springs back when pressed lightly, leaving no dent. A skewer in the centre comes out with moist crumbs clinging to it, not wet batter.	Doneness test

3.79 x 1.34^1.3 x 50.3^0.45 x (350 / 350)^1.5

This is a computed starting point from the pan geometry, NOT a tested time. Nobody baked a cake with a stopwatch to produce it. Home ovens commonly run 25 F from their dial, which moves a bake time further than this whole band, so the doneness test decides.

The formula

minutes = 3.79 x depth^1.3 x area^0.45 x (350 / temp F)^1.5

It is worth being plain about where this comes from, because most bake-time charts do not say. It is arithmetic on the pan dimensions, and the exponents are what matter: batter depth carries the largest one because heat travels in from the wall and up from the floor, floor area matters less, and temperature enters as roughly its inverse three-halves power.

The band is wide on purpose. A home oven reading 350 F on its dial is routinely 25 F out in either direction, which moves a bake time further than any of this arithmetic does. An oven thermometer is the cheapest useful thing you can buy for baking.

Past about 12 inches the outside of a cake sets long before the middle. Bake-even strips and a heating core are the usual answers, and both change the time.

Derived, published or convention?

This is TRADE CONVENTION and a COMPUTED ESTIMATE. Nobody baked a cake with a stopwatch to produce it, and no figure here should be treated as tested. The doneness tests below are what actually decide.

Estimated bake time by pan, filled two thirds
Pan	Batter depth (in)	Oven (F)	Start checking (min)	Expected range (min)
6 in round	1.33	350	20	20 to 30
8 in round	1.33	350	25	25 to 40
9 in round	1.33	350	30	30 to 45
10 in round	1.33	325	35	35 to 55
12 in round	1.33	325	45	45 to 65
14 in round	1.33	325	50	50 to 75
8 x 8 in square	1.33	350	30	30 to 45
10 x 10 in square	1.33	325	40	40 to 60
9 x 13 in rectangle	1.33	350	40	40 to 60
12 x 18 in rectangle	1.33	325	60	60 to 85

Computed estimates from pan geometry, not tested times. The oven temperature follows the convention of 350 F under a 10 inch span at 2 inches deep, and 325 F above that or for 3 inch pans.

Gear for these numbers

These are rendered from the verified catalog and re-ordered against your numbers once you calculate.

Beginner

Taylor

Taylor Large 2.5 Inch Dial Oven Thermometer

$8.28

Home ovens routinely run 25 F or more off their dial, which is the real reason a bake time chart never matches your oven, and this is the cheapest way to find out by how much.

Best for: finding out what your oven actually does

Check price on Amazon

Amazon prices move often, so check before you buy.

Beginner

Wilton

Wilton Bake-Even Cake Strips, 2 Piece Set

$10.99

Damp strips around the pan slow the outside so the middle catches up, which is what stops a dome forming and saves you levelling off the top and throwing it away.

Best for: flat layers with no trimming

Check price on Amazon

Amazon prices move often, so check before you buy.

Intermediate

ThermoWorks

ThermoWorks Classic Thermapen Instant-Read Thermometer

$105.00

The older Thermapen at a lower price, slower to read than the ONE but with the same probe accuracy, which is the part that matters for tempering.

Best for: accurate readings without the flagship price

Check price on Amazon

Amazon prices move often, so check before you buy.

Questions people ask

How do I tell when a cake is actually done?: The middle springs back when pressed lightly and leaves no dent. A skewer in the centre comes out with moist crumbs clinging to it rather than wet batter. The edges have pulled very slightly away from the pan wall, and the surface has stopped hissing, which is the sound of water still boiling off. Any one of those beats a clock.
Why is the bake time a range rather than a number?: Because a single number would be false precision. This figure is computed from pan geometry rather than measured, and home ovens commonly run 25 F away from their dial in either direction, which shifts a bake time by more than the whole range. Treat the low end as the moment to start checking and let the doneness test decide the rest.
Should I bake at 325 F or 350 F?: The convention is 350 F for layer pans under a 10 inch span at 2 inches deep, and 325 F once the shortest span reaches 10 inches or the pan is 3 inches deep. Dropping 25 F always costs time and always gives a flatter, paler cake, so it is a trade rather than an improvement. A 9 by 13 bakes at 350 F despite its area, because no part of it is more than 4.5 inches from a wall.
Do bake-even strips change the bake time?: Yes, usually adding a few minutes, and they are worth it anyway. A damp strip around the pan slows the outside so the middle catches up, which stops a dome forming. The cake finishes flat enough to stack without levelling, so the extra minutes buy back the cake you would otherwise cut off the top and throw away.

Worked out for you already

A note on what this can and cannot tell you

This calculator does arithmetic on the numbers you give it. It does not know your oven, your recipe or your altitude. Figures are labelled as derived, published or trade convention, and where no honest figure exists the calculator says so instead of producing one. Researched guidance, not professional advice.