Guide · updated 10 November 2026

9V battery voltage: how to test a 9V battery with a multimeter

A new 9V alkaline battery reads about 9.50 V on a multimeter, not 9 V. One that reads exactly 9 V is already partly used. This page has the chart, the steps, and the one detail of the 9V battery that helps you read it: it is six small cells in a row.

iPhone and iPad (iOS 17 or later): free on the App Store. Android later.

The chart: 9V alkaline at rest

9V alkaline: voltage at rest
Verdict	Voltage at rest	What it means	What to do
FULL	9.30 V and up	As good as new.	Ready for use.
GOOD	8.70 to 9.30 V	Plenty left.	Ready for use.
WEAK	7.80 to 8.70 V	Most of the charge is used.	Fine for clocks and remotes. Swap it soon in anything that draws more.
REPLACE	under 7.80 V	Empty for most devices.	Replace it, and recycle the old one.

Measured at rest, with nothing connected. A reading exactly on a boundary counts as the higher band.

How to measure it

Take the battery out of the device and wait a minute.
Set the multimeter to DC volts. On a meter without auto-range, pick the 20 V range.
Touch the red probe to the smaller, round snap: that is plus. Touch the black probe to the larger snap: that is minus.
Hold the probes still until the digits settle, and read the voltage with one or two decimals.
Look it up in the chart.

A minus sign on the display means the probes are swapped. Swap them: nothing is damaged.

Six cells in one box

A 9V alkaline battery holds six 1.5 V cells in series. That explains two things:

The scale. Its bands are six times the bands of one alkaline cell, rounded.
A sudden low reading. One dead cell among the six pulls the battery down by about 1.5 V. A battery that reads far lower than its age suggests has probably lost a cell: replace it.

At rest and under load

The chart is for a battery at rest, with nothing connected. Devices stop at lower voltages, because they measure the battery while it works: datasheet tests run a 9V battery down to between 5.4 and 7.2 V under load, depending on the device. So a battery under 7.80 V at rest is empty for most devices, even though it still shows several volts. A battery that reads WEAK belongs in something that draws little, not in a device you rely on.

Other 9V chemistries

This chart is for alkaline 9V batteries. Rechargeable and lithium 9V batteries follow other scales, so do not judge them with it. The label says which chemistry you have.

The shortcut in the app

Coming Coming in an app update. It is not in the app you can install today.

The battery tester in TestNMeasure has a 9V tile. Pick it, touch the probes to the snaps, and the app shows FULL, GOOD, WEAK or REPLACE with the next step. More: Battery tester.

The app you can install today already shows the meter's reading large on your phone, with five stability bars that light when the reading is steady. One tap saves the reading with a label and a note, such as which device the battery came from.

Where the numbers come from

The bands come from the alkaline handbook and the 9V datasheet of a battery maker (Energizer) and common battery testers. They are the bands the app uses. You can also type a reading into the battery checker, or start from the general guide: how to test a battery with a multimeter.

What the app does here, and what it doesn't

What it does
What it does	Plan
Pick the battery type and see FULL, GOOD, WEAK or the end of its life from the DC volts, with the next step.	Free Coming
A large readout that shows which digits have settled; OL and UL are shown as OL and UL, never as a number.	Free
Five stability bars show when a reading is steady.	Free
One tap saves the current reading, with an Undo.	Free
Add a text note and a short label to any capture.	Free

Not yet, or not planned

No load test: the battery tester reads the voltage without load, so it cannot show a car battery's cranking strength.
Reads what your meter measures; it doesn't change the meter's accuracy or ranges.

Questions

At what voltage is a 9V battery dead?

At rest, under 7.80 V an alkaline 9V battery is empty for most devices: replace it. Devices themselves stop between 5.4 and 7.2 V, measured while the battery works.

How to test a 9V battery without a tester?

Use a multimeter. Set it to DC volts, touch red to the smaller round snap and black to the larger one, and read the voltage. From 8.70 V the battery is GOOD, from 9.30 V it is FULL.

How to tell if a 9V battery is expired?

The date printed on it is a best-before date, not a test. Measure it instead. If it reads 8.70 V or more it is GOOD whatever the date says, and under 7.80 V it needs replacing even if the date has not passed.

Try it in the demo

A simulation of the app in your browser, with made-up readings: no meter and no install needed.

Try the battery tester in the demo Coming

Get TestNMeasure for iPhone and iPad.