The short answer
Buy the BOV845 Smart Oven Pro if your counter is a normal counter and the jobs are toast, baking, roasting and reheating. It draws the same 1,800 watts as the bigger oven, runs the same Element IQ control, and costs meaningfully less. Buy the BOV900 Smart Oven Air Fryer Pro if you want air fry or dehydrate as named functions, a Proof setting that runs at 80–100°F, nine slices instead of six, or a published one-cubic-foot interior — and you have 21.4 inches of width and 17.3 of depth to give it.
That is a real choice, which makes this pair unusual for Breville. The BOV900 and the BOV950 are the same oven with a radio added. The BOV860 and the BOV900are the same electronics in two widths. The BOV845 and the BOV900 differ in the element count, the fan, the rack system, the temperature band and the function list, and every one of those differences is printed in Breville's own documents. What follows is read off the two instruction books, side by side.
What is identical
Rated power.Both are 1,800-watt ovens. For the BOV900 that is the Rating Information line printed in Breville's instruction book — 120 V ~ 60 Hz 1800 W. For the BOV845 it is the figure on Breville's product page, which the site scores slightly differently (a product-page figure is brand-published but not a rating plate), but it is the same number either way and the running cost that follows from it is the same to the cent. Both sit in the wattage table.
Element IQ. Both books describe it in the same words: a technology that adjusts the power of the heating elements to cook food more evenly and quickly, with each function preset to a recommended setting you can override, and the override remembered until the oven is unplugged. Both are brushed stainless steel, both have an LCD, both have an interior light that comes on at the end of the cycle, both ship with a 13-inch non-stick pizza pan, and both books ask for the same clearance: four inches on each side and six above.
The magnetic auto-eject rack. Both have it, and it is worth knowing it is not a BOV900 exclusive. On the BOV845 the wire rack ejects halfway when the door opens if it is in the middle position; on the BOV900 it does so in positions 3 or 4. Both books carry the same warning to open the door slowly when the rack is there.
What the Air Fryer Pro adds, row by row
Everything in this table is a figure Breville publishes for both ovens, either on the product page or in the instruction book. Where Breville publishes a number for one oven and not the other, the cell says so rather than guessing.
| What Breville publishes | BOV845 Smart Oven Pro | BOV900 Smart Oven Air Fryer Pro |
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| Rated power | 1800W (product page) | 1800 W (rating plate, instruction book) |
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| Quartz elements | 5 | 6 |
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| Convection fan | One convection setting | Convection and super convection (two speeds) |
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| Functions | 10 | 13 (adds Air Fry, Proof, Dehydrate) |
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| Bake / Roast range | 120–450°F | 120–480°F |
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| Lowest set point | 120°F (Bake, Roast, Reheat, Warm) | 80°F (Proof, 80–100°F) |
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| Broil | Three presets: 500°F, 400°F, 300°F | Low, Med, High (no temperature stated) |
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| Rack positions | 3 (one rack) | 8 (two reversible racks) |
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| Toast | 1–6 slices | 1–9 slices |
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| Interior | Not published | 1 cubic ft |
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| Exterior (W × D × H) | 18.9 × 15.9 × 10.9 in | 21.4 × 17.3 × 12.7 in |
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| Pan included | 12 × 12 in enamel baking pan and broiling rack | 9 × 13 in enamel roasting pan and broiling rack, plus air fry/dehydrate basket |
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| Slow cook | LO 4–10 hr, HI 2–8 hr | LO 4–72 hr, HI 2–12 hr |
|---|
Five elements against six, and one fan speed against two
This is the difference that is easiest to miss and hardest to argue with, because it is hardware. Breville's BOV845 page says Element IQ transfers heat across five quartz elements; the BOV900 page says six independent quartz heating elements. Six independently driven elements is what the site's BOV900 reviewcalls the mechanical substance behind that oven's price, and the Smart Oven Pro has five.
The fan is the other half. The BOV845 has a convection button that turns the fan on or off — one speed, and Breville's claim for it is that the convection setting reduces cooking time by up to 30 percent. The BOV900's book says its convection button chooses between no convection, convection and super convection, and that super convection “will deliver crispier food result.” Super convection is the mode Air Fry and Dehydrate run in by default. It is the higher fan speed, and it is the entire reason the BOV900 can carry an air fry label and the BOV845 cannot. What an air fry setting actually is, mechanically, is here.
The three functions the BOV845 does not have
Ten against thirteen, and the three are named: Air Fry, Proof and Dehydrate. Breville's product page lists the Smart Oven Pro's ten as Toast, Bagel, Bake, Roast, Broil, Pizza, Cookies, Reheat, Warm and Slow Cook, and the instruction book's contents page lists exactly the same ten. Each of the missing three is worth a sentence.
Air Fryon the BOV900 is a preset of 400°F for eighteen minutes in super convection on rack position 3, adjustable from 120°F to 480°F, in the mesh basket. The BOV845 has no basket, no super-convection speed and no such preset; you can roast at 450°F with the fan on, which is what the site's convection-versus-radiant comparison would tell you to do, but Breville does not call it air frying and neither do we.
Proof needs saying carefully, because it is widely misdescribed — this site included, until this page was written. The BOV845 has no Proof preset. What it has is a published floor of 120°Fon its Bake, Roast, Pizza, Cookies, Reheat and Warm functions, which is a low set point for the category and a real, checkable specification. But the BOV900's Proof function runs at 80–100°F, preset 85°F, for up to two hours — and the top of that band is twenty degrees below the lowest number the BOV845's dial reaches. If proofing dough at a proofing temperature is the job, the BOV900 publishes a setting for it and the BOV845 does not.
Dehydrateon the BOV900 runs 86–176°F, preset 125°F for twelve hours, adjustable to seventy-two, in super convection on rack 3, and Breville states it will take four trays. The BOV845's longest cycle is the ten-hour LO slow cook, and its lowest set point is 120°F with a single fan speed. The ovens that can genuinely dehydrate are ranked here, on published floors.
The temperature band, function by function
Headline ranges hide more than they show, so here are the books' own tables. On the BOV845, Bake, Roast, Pizza, Cookies, Reheat and Warm all run 120–450°F — the presets are 325°F, 350°F, 450°F, 350°F, 325°F and 160°F respectively — and Broil offers three fixed temperatures, 500°F, 400°F and 300°F, for up to twenty minutes. So the Smart Oven Pro's true ceiling is 500°F, but only on Broil; on every convection function it stops at 450°F.
On the BOV900, Bake, Roast, Pizza, Cookies, Reheat and Air Fry run 120–480°F, Proof runs 80–100°F, Dehydrate runs 86–176°F, and Broil is Low, Med or High with no temperature printed at all. That gives the bigger oven a 30°F higher ceiling on every baking function and a 40°F lower floor via Proof, while the smaller oven is the one with a numbered broil. Neither is a flaw; they are two different sets of choices, and the reader who bakes at 475°F or proofs at 85°F now knows which oven publishes that number.
The timers differ more than the temperatures. The BOV845 allows up to two hours on Bake or Roast above 300°F and up to ten hours below it; the BOV900 book bands its long cooks by temperature and allows up to seventy-two hours below 210°F, which is what makes its seventy-two-hour LO slow cook and its seventy-two-hour Dehydrate possible. If an overnight cook is a real habit, the BOV900 is the one whose book says yes.
Three rack positions against eight
The BOV845 ships with one wire rack and three rack heights — top, middle and bottom — printed beside the oven door, with the book assigning Broil to the top, Toast, Bagel, Pizza and Cookies to the middle, and Bake, Roast, Reheat, Warm and Slow Cook to the bottom. The BOV900 ships with two wire racks, each reversible, so four grooves give eight rack heights, and the book suggests positions 3 and 7 or 4 and 8 for two-tray cooking. It also has two things the BOV845 book does not describe at all: a door sensor that pauses the timer while the door is open and shuts the heaters off if it stays open ten minutes, and Rotate Remind, an alert to swap trays part-way through a multi-rack cook.
Whether that matters comes down to one question: do you cook on two levels at once? Two sheet pans of vegetables, two trays of cookies, a roast below a pan of potatoes. If yes, the BOV900's eight positions, second rack and rotate reminder are the feature, not the interior volume. If you cook one tray at a time, three positions is exactly as many as the BOV845 book ever asks you to use.
What fits, on Breville's own numbers
The BOV900 publishes a one-cubic-foot interior and a list of what it takes: nine slices of toast, a 14-pound turkey, most 9 × 13 pans and 12-cup muffin trays, a 5-quart Dutch oven, a 13-inch pizza, four dehydrating trays. The BOV845 publishes no interior volume, and its stated fits are six slices, a pizza from 6 to 13 inches, and the 12 × 12 enamel pan it ships with. On a site that scores documentation, that is a real gap between them, and it is the reason the bigger oven scores higher on usable space even before its extra 2.5 inches of width is counted.
The width is the practical constraint. At 21.4 inches wide and 17.3 deep before the clearance a drop-down door needs, the BOV900 is the largest footprint this site covers; the BOV845 at 18.9 by 15.9 is the width of a normal upper-cabinet gap. Measure the four dimensions on this page before ordering either, and remember both books want four inches clear on each side and six above.
Running cost: the same, to the cent
Both ovens are rated 1,800 watts, so both cost exactly the same per hour at full draw, and the cards above show the arithmetic step by step. The BOV900 will not cost more to run because it has more elements — Element IQ steers a fixed budget of power, it does not add to it — and the BOV845 will not cost less because it has fewer. The only honest running-cost claim is the one about air: the BOV845 is heating a smaller cavity, so a given preheat is done sooner. The convection electricity page walks through the hourly arithmetic. Neither should be bought to save on the bill.
The row we will not put in a table
Warranty. Breville prints no warranty term in the BOV845 specification panel as we read it, and the BOV900 card above carries none for the same reason. The terms Breville does publish live on its warranty and repairs pages, not beside the specs, so if length of cover decides this for you, read it there rather than taking a number off any review, including this one.
The decision rule
Buy the BOV900 if any of these is true: you want Air Fry or Dehydrate as a real preset, you proof dough and want a setting that runs at 80–100°F, you cook on two racks at once, you toast for more than six, or you need Breville to have told you what fits. Buy the BOV845 if none of them is, because it is the same 1,800 watts and the same Element IQ in a chassis that fits a normal counter, for a lot less. Running cost is identical — so the decision has no consequence for your bill, only for your counter and your recipes.
A note on the middle path. If the only thing pulling you to the BOV900 is the air fry label, the oven you are actually looking for is the BOV860 Smart Oven Air Fryer— the BOV845's 18.9-inch chassis with Air Fry added and a basket in the box. The BOV845 review and the BOV900 reviewcarry each oven's full published spec.
If neither is the answer
The Breville range now has a review at every rung. Below this pair, the BOV680 compact takes the full 1,800 watts down to a 15.7-inch chassis with a published 120–445°F band. Above it, the BOV950 Joule Oven is the BOV900 with Wi-Fi, and that comparison settles whether the app is worth it. Outside Breville, the Cuisinart TOB-260N1 is the oven to weigh against the BOV845 for baking — it publishes a 0.95-cubic-foot interior the Breville does not — and the bread ranking puts the two side by side.
