Index / Sizes / 9V

9V (9 volt) batteries: every designation in the size

A 9V is a shape, not a specification. 5 designations share it here, running 150 to 1100 mAh, a spread of 7.3 times, and they do not all deliver the same voltage: 7.2 V, 8.4 V and 9 V.

9V is a name, and the name covers a range

The 5 designations sold as 9V in this data are not one size. Across them the diameter runs 17 to 17.5 mm and the length runs 44.5 to 49 mm, a spread of 0.5 mm across and 4.5 mm along.

The longest is 1604LC at 49 mm and the shortest AC146X at 44.5 mm; the widest is 6LR61 at 17.5 mm and the narrowest AC146X at 17 mm. This site treats anything inside 0.3 mm as a drop-in, because that is the order of the spring travel in a contact, not a round number. The 4.5 mm along this size is wider than that tolerance, so the ends of the range are not interchangeable on length alone.

9V battery voltage: one name, 3 different voltages

A compartment marked 9V takes any of them, and that is the whole difficulty: the fit says nothing about the electrics. Between the lowest and the highest here the difference is 7.2 V against 9 V, or 20.0% of the nominal figure.

• 9 V — 3 designations: 6LR61, 6F22 and 1604LC
• 8.4 V — 1 designation: AC146X
• 7.2 V — 1 designation: 7.2H5

What that costs depends on what the device does with the figure rather than on the figure itself. A motor or a lamp runs slower and dimmer and comes to no harm. A meter, a scale or a thermometer reads the cell as part of its own reference and reports a number that is wrong by about the same 20.0. A circuit with a regulator either holds its output or cuts out early, and which of them it does is not printed on the case. This site never answers that question for a device it cannot see; it gives the figure and names the class of consequence.

How much energy is actually in there

Milliamp-hours cannot be compared across chemistries. A milliamp-hour at 9 V carries more energy than a milliamp-hour at 7.2 V, and the capacity column hides that. Multiplying the published capacity by the published voltage puts every designation called 9V on one scale, and on that scale the range is 8.6 times wide — AC146X carries about 9240 mWh and 7.2H5 about 1080 mWh.

• AC146X — 9240 mWh (1100 mAh at 8.4 V)
• 6LR61 — 5085 mWh (565 mAh at 9 V)
• 6F22 — 2970 mWh (330 mAh at 9 V)
• 7.2H5 — 1080 mWh (150 mAh at 7.2 V)

These are the maker's own figures at the maker's own test load, and a cell asked for more current than that test uses delivers less. The number is a ceiling and a way to compare, not a promise of runtime in a particular device.

The compartment takes any of them; the circuit does not

5 kinds of chemistry are sold as 9V in this data, and the difference between them is not a difference of size. A holder marked 9V closes on all of them, so nothing about the fit warns anybody which one the device was designed around. What follows is what each kind does that the millimeters do not say.

• Alkaline (1 designation here) drops in voltage steadily as it empties, so a device calibrated for a flat discharge will drift as it goes.
• Carbon zinc (1 designation here) carries a fraction of the capacity of an alkaline cell of the same size and leaks more readily when spent.
• Nickel-metal hydride (1 designation here) is rechargeable and sits at 7.2 V, below the nominal of the primary cell whose slot it takes. It is never a drop-in for a primary cell no matter how well it fits, and a device that cuts off early will read it as flat.
• Lithium (1 designation here) runs at 9 V, roughly six times the nominal of the alkaline and silver classes. Of the 24 lithium cells here whose envelope the maker publishes, 3 share that envelope with an alkaline or silver cell.
• Zinc air (1 designation here) takes oxygen from the air through the holes in its face. It starts discharging the moment the tab comes off and runs down in weeks whether the device is used or not, and a sealed compartment starves it.

None of this is a recommendation for a particular device. The device decides: a lamp tolerates almost anything that fits, a meter reports a number that is wrong by whatever the voltage is wrong by, and a sealed compartment is the one case where a zinc-air cell cannot work at all however well it sits. Where the maker of the equipment names a chemistry, that naming outranks every figure on this page.

Also stamped on cells in this table: 6LR61, 1604A, 522, 522 ALKALINE POWER, A522V, EN22, X22, EP522, 6LF22, 6F22, 1604D, 1222, 1604, 216, EV122, EV22, 7.2H5, NH22-150MAH, NH22-175MAH, 1604LC, L522, L522MJ, LA522, LN522, AC146X.

What stands next to this size in the data

The envelope above is not the only one near it. Cells that miss by a fraction of a millimeter sit in the same drawer and look identical in the hand, and the question they raise is the one this site answers: not whether a cell is the same, but what the difference does. These are the nearest envelopes to 9V in this data, closest first.

• 26.2 x 16 x 51 mm — is too narrow to hold contact, first met here as 15F20.
• 28.2 x 14 x 51.6 mm — is too wide to enter, first met here as CRV3.
• 35.6 x 9.2 x 48.5 mm — is too wide to enter, first met here as 4LR61.
• 26.2 x 16.1 x 37 mm — is too narrow to hold contact, first met here as 10F20.
• 15.1 x 15.9 x 50.9 mm — is too narrow to hold contact, first met here as 15F15.
• 33.3 x 24.6 x 39.7 mm — is too wide to enter, first met here as 417.

None of the nearest would drop straight in on size alone. Every verdict in that list is about the compartment alone. A cell that drops in physically can still be the wrong cell: the voltage and the chemistry are separate questions, answered separately above and on the page of each designation. Nothing here says a substitution is safe for a particular device, and where the maker of the device names a cell, that naming outranks every millimeter on this page.

What is gone from this size

1 designation of the 5 here is no longer listed by Energizer: AC146X. The compartment is the same size for the rest, and that is the only thing the size settles.

Fit answers whether it enters the compartment; every cell here shares the envelope, so fit is already settled. Voltage answers whether the circuit will notice, and chemistry answers what the voltage column cannot say. A cell that fits is not always a safe substitute.

Before you swap anything

Everything here is computed from published dimensions and nominal voltages. That answers whether a cell enters the compartment and whether the voltage matches on paper. It does not answer what your device does with the difference, and it cannot: a cell that fits can still be the wrong cell.

One more limit, and it is the biggest. This site reads a single manufacturer’s catalog. When a page says a designation is not listed, that means Energizer no longer offers a part under it — not that nobody makes the cell. Other makers may still sell it, and for common sizes they usually do.

A voltage difference is one relation between two cells, and this page prints it from the cell it is about — in every table on the page, including the one listing cells no longer made. A figure always belongs to the cell whose voltage is printed beside it: a cell that runs lower than this one carries a minus here, one that runs higher carries a plus, and two cells at the same nominal voltage carry zero. Meet the same pair on the other cell’s page and the sign is the other one, with the figure taken against that cell instead of this one; where the two run at the same voltage, both pages print zero. The class beside the figure is not read off that figure directly. It is decided on the gap itself, taken against the higher of the two nominal voltages, so one pair of cells gets one class whichever page you meet it on: counted from this side the boundary of the class that still runs falls at 20.0% below and 25.0% above, which is the same gap divided once by the larger nominal and once by the smaller. What genuinely differs between the two directions is the consequence, and the words carry it: a cell that runs low makes a calibrated instrument read below true, and a cell that runs high makes it read above.

3 things this site cannot see. Whether the contacts reach a shorter cell. Whether the device was calibrated for a chemistry that holds its voltage flat, which silver oxide does and alkaline does not. Whether the equipment tolerates the higher current a different chemistry can deliver. Rechargeable cells are never a drop-in for primary cells regardless of size.

Where these numbers come from

Dimensions, voltages, chemistries and capacities are published by the manufacturer and reproduced without change. Everything else on the page is ours, computed from those figures: whether one cell fits where another sat, how far apart their voltages are, stored energy and energy per cubic centimeter, the rank within a shell, and the check of the designation against the measured size.

Fit is decided within 0.3 mm on every axis, which is the order of a contact spring's travel. Voltage classes are decided by consequence, not by roundness, and they are decided on the gap between two nominal voltages taken against the higher of the two: 2.0% or less of it is the same working voltage, 6.0% starts to matter to a calibrated instrument, and past 20.0% it is a different class altogether. Measuring the gap against the higher figure is what makes the verdict the same from either cell’s page, while the printed percentage stays counted from the cell you are reading about. Cells with identical stored energy share a rank instead of being ordered arbitrarily.

Ranking uses capacity times nominal voltage, because capacity alone is not comparable across chemistries: 150 mAh at 3 V is twice the energy of 150 mAh at 1.5 V. Neighbors are chosen by measurement and never alphabetically, because two cells filed next to each other by name usually have nothing in common. A blank in any table means the maker publishes no figure, which is not the same as zero.

Source: Energizer technical data, retrieved 1 September 2026.