Every dollar figure on this page is priced at NSW's regulated reference rate, the largest state's. Rates elsewhere run higher and lower, and our washing machine calculator reprices any registered model on your own state's.
What the register shows when you sort by size
The energyrating.gov.au registration database tests every clothes washer sold in Australia the same way and publishes the result, which means the whole market can be grouped by rated capacity and read off rather than guessed at. Two things have to be held still for that grouping to mean anything. Loader type is one, so this page reads front loaders only. Machine type is the other: the register also lists combination washer-dryers, and it tests those with the drying switched off, so their kWh figure covers half of what the machine does. They are counted out here, the way our 10kg league table counts them out, because their share of a size class swings from 13% to 26%, and one class cannot be weighed against another when the mixture inside them differs that much.
That leaves 789 plain front loaders out of the 1,002 registered, every one of them carrying a rated capacity, so all of them sort into a class. Seven of those classes hold 20 or more models between them, 754 machines in total. Sorted by what they cost to run, the 10kg class lands at the cheapest end and the 6kg class seventh of the seven. The bigger machine wins, on a bill that includes no assumptions about how full anyone loads it.
The lean is not a ladder, though, and the table below says so plainly. Walk it in size order and two of its six steps go up rather than down (9kg over 8kg and 11kg over 10kg), so cost does not fall class by class as capacity rises. The top of it needs care, too: the three dearest classes (6kg, 7kg and 11kg) are also the three smallest samples, at 28, 20 and 23 models against the hundreds the big classes carry. So "buy bigger" is a bet that pays more often than not, not a saving anyone can count on.
The margin is the real story here. From the cheapest capacity class to the dearest is $28.72 a year. Inside the single 8kg class, the gap between the most and least efficient machine is $102.20 a year, about 4 times wider. Anyone choosing a smaller drum to keep the running cost down is optimising the variable that barely matters and leaving the one that does to chance.
Every capacity class, plain front loaders
| Rated capacity | Plain models | Median kWh per load | Cost a year |
|---|---|---|---|
| 6kg | 28 (thin sample) | 1.00 | $84.47 |
| 7kg | 20 (thin sample) | 0.89 | $75.18 |
| 8kg | 217 | 0.67 | $56.59 |
| 9kg | 161 | 0.72 | $60.82 |
| 10kg | 223 | 0.66 | $55.75 |
| 11kg | 23 (thin sample) | 0.88 | $74.33 |
| 12kg | 82 | 0.80 | $67.57 |
| Every other size | 35 across 8 classes | None big enough to median | |
Median of each class's own labelled kWh-per-load figure, priced at NSW's reference rate for 2026–27 and 5 loads a week, the same default our washing machine calculator uses. The Models column adds up to the 789 plain front loaders, which is what the last row is for, and the 201 combination washer-dryers and 12 machines the register leaves unclassified are the rest of the 1,002 registered. Those plain machines run from 2kg to 20kg across 15 capacity classes, and those 35 machines sit in classes too small to carry a median at all (17 compact machines under 6kg, 18 commercial-sized ones over 12kg). One rule decides the flags, applied by number rather than by which way a class points: a class needs 20 models to earn a printed median, and under 50 it keeps a thin-sample tag, so all three classes under it (6kg, 7kg and 11kg, at 28, 20 and 23 models) carry the tag whether they help the answer or not. Every class is cheaper than the worst single 8kg machine on the list, which costs $136.84 a year.
Why bigger usually costs less, and where it does not
A wash cycle spends most of its energy heating water and turning a drum, and neither of those costs scales cleanly with how much is inside. A 6kg machine still has to heat a tub, still has to run a motor, and still has to run a full cycle to wash a single work shirt. Per kilo of rated capacity, the median 6kg front loader draws 0.167 kWh against the 10kg machine's 0.066, about 2.5 times as much. The larger drum is spreading the same fixed overhead across more clothes. That mechanism sets the direction, not the size of the gap, which is why the dearest classes on the table are also the worst sampled: with samples under 50 machines, which brands happen to be registered matters more than the physics does.
The same shape shows up in top loaders, which is the check worth doing before believing any pattern found in one loader type. The median 6kg top loader (59 models) draws 1.17 kWh a load, $98.83 a year. The median 10kg top loader (76 models) draws 0.96, $81.09. Bigger is cheaper there too, and by a wider margin, though both figures sit well above the front-loader numbers for the reason our front load versus top load guide sets out.
How often the rule actually holds
Medians describe a class, not a machine, so the honest version of this finding is counted one model at a time. Of the 223 plain 10kg front loaders, 180 (81%) run cheaper than the typical 6kg. Going the other way, just one of the 28 plain 6kg machines beats the typical 10kg. So a large machine is usually, not always, the cheaper one, and a small machine is rarely the cheaper one. Neither statement is strong enough to buy on by itself.
What to do with this in a showroom
Pick the capacity that suits the household's actual washing, then choose on the tested kWh figure inside that size. A drum too big for the load pile does not cost extra to run, but it does cost extra to buy, and a drum too small means more cycles, which is the one way size genuinely raises a bill: two loads at 1.00 kWh cost more than one at 0.66. Once the size is settled, the number on the Energy Rating Label is worth more than the badge on the door, as our premium brand guide found, and the cheapest 8kg machines to run shows what the efficient end of one size class looks like.
Common questions
Does a bigger washing machine use more electricity?
Usually not, though the register is not tidy about it: two of the six steps up the size table (9kg over 8kg and 11kg over 10kg) draw more per load than the size below them, so the trend is not something to buy on one step at a time. The bigger effect is behavioural anyway. The one way a bigger drum reliably raises a bill is by tempting more cycles out of it, and that is worth putting a figure on: one extra wash a week on a typical 10kg front loader costs $11.15 a year at NSW's reference rate, against the $28.72 a year the bigger drum saves over a typical 6kg. So an added load a week gives back about 39% of what the size bought. Buy the capacity the washing pile needs, not the one that invites a half-empty cycle.
Is a 10kg washing machine cheaper to run than an 8kg one?
By about $0.84 a year at five loads a week, which is close to nothing. The two classes sit first and second once the classes are ranked by cost, the way the panel at the top of this page shows them, and are separated by 0.01 kWh a load. Treat 8kg and 10kg as the same running cost and decide between them on how much washing the household actually does.
If size barely matters, what does?
The specific model, and the size classes overlap far too much to buy on size alone. The most efficient machine in the dearest class on the table, 6kg, draws 0.45 kWh a load. The least efficient machine in the cheapest class, 10kg, draws 2.22, about 4.9 times as much. The two classes overlap almost exactly: 96% of the 6kg class sits inside the range of the 10kg one, and the rest of it sits below that range's cheapest machine. Our star rating guide explains how to read that figure off the label, and our washing machine calculator prices any registered model on your own state's rate.
Why do the 6kg, 7kg and 11kg classes look more expensive than their neighbours?
Because they are small classes, and on this table the three dearest classes are exactly the three smallest samples. Only 28, 20 and 23 plain models sit at 6kg, 7kg and 11kg respectively, against 217 at 8kg and 223 at 10kg, so a handful of inefficient machines moves those medians in a way it cannot move the big classes. They are shown in the table and in the chart above it with the sample size beside them rather than hidden. The steadiest reading of the trend comes off the four classes above 50 models (8kg, 9kg, 10kg and 12kg), and even there the whole spread is worth less than picking a good machine inside one size.
Does this hold for top loaders as well?
Yes, and more strongly, though the comparison worth making is against front loaders rather than within top loaders. Only 100 of the 342 plain top loaders (29%) use less per load than the median machine in the dearest front-loader size class, so 71% of top loaders lose to the worst size of front loader you could pick. Hold capacity still at 10kg and the loader-type choice is worth $25.34 a year. The size choice, between a 6kg and a 10kg front loader, is worth $28.72. On this register the two are worth about the same, which is not what the showroom would tell you about either.
Sources
Per-model kWh-per-load figures and rated capacities: the energyrating.gov.au registration database (July 2026 snapshot), the same file our washing machine calculator's model finder reads, filtered to the 789 front loaders and 342 top loaders the register marks as plain washing machines, out of 1,002 and 346 registered, then grouped by rated capacity in kg and reduced to a median per group. Combination washer-dryers are left out because the register tests them with the drying switched off, so their figure covers half of what the machine does, and their share of a class runs from 13% to 26%, which would make the classes incomparable with each other. Every plain washer reports a capacity, so that grouping drops nothing: the table prints a median for each class carrying 20 or more models and totals the remaining 35 machines in a labelled row, which is why its model column sums to the full 789. Each count and median on this page is read out of that file when the page is built rather than typed in, so the headline figure and the table are two views of the same query. The 8kg group's median and range match our star rating guide's figures exactly, which is the cross-check that the two pages cannot drift apart. Electricity rate: AER Default Market Offer, NSW's regulated reference tariff, current for 2026–27. Frequency: 5 loads a week, the washing machine calculator's own default. This guide is general information, not a recommendation to buy any specific model; check current retail availability and price before deciding. All fetched July 2026.