Battery capacity: what mAh means and how to read it

What battery capacity means in plain words

Think of the battery as a water tank. The mAh number tells you how large the tank is, and the phone is the tap that drains it. A phone with a bright, fast screen opens the tap wider than a simple phone with a small screen, so two phones with the same tank can run for very different hours.

The figure is measured at the cell, not at the screen. It describes what the pack can store when new, under test conditions. Every month of use and every hot day takes a little away, which is why an old 5000 mAh pack behaves like a smaller one.

The same number appears under different names. Makers and buyers say battery capacity, capacity of battery, battery size or battery power, and all of them point to the mAh value. None of them tells you the battery code, which is a separate label. Cell codes are explained in our guide to reading battery labels.

Two numbers for one pack: minimum and typical

Many makers print two figures. The minimum (rated) value is the lower number promised for every pack that leaves the factory. The typical value is what a normal pack measures, and it is the one used in launch posters. A phone sold as 5000 mAh often carries 4900 mAh rated alongside 5000 mAh typical.

The gap is small, usually a few percent, and it is not a trick. It only means that production varies a little. When a page on this site gives a capacity, it says which of the two it is. A number printed on your own battery label is the one to trust.

From mAh to watt hours: a fairer way to compare battery capacity

mAh ignores voltage, and voltage differs between cells. Watt hours (Wh) include it, so Wh is the cleaner measure of stored energy. Watt hours equal mAh times the nominal voltage, divided by a thousand.

• 5000 mAh at 3.87 V comes to roughly 19.4 Wh.
• At 3.85 V, 6000 mAh is about 23.1 Wh.
• Two packs of equal mAh with different voltages will not hold equal energy.

Apple does not lead with mAh. Apple's documents use watt hours and video playback hours for iPhones; the mAh figures you see elsewhere come from filings and teardowns. See the iPhone battery capacity page for the model by model view.

Battery time estimator: turn mAh into rough hours

This page's estimator takes a capacity in mAh and a usage style, light, mixed, heavy or gaming. It then estimates screen on time and a standby range. It works from a typical average current draw for each style and divides your capacity by that draw. It stores nothing.

Please remember that it gives an estimate, not a test result. Your own phone may do better or worse because of its screen, signal, brightness and apps.

The simple rule behind it: hours equal capacity divided by average draw in mA. A pack of 5000 mAh feeding a steady 500 mA would last close to 10 hours before losses. Real phones do not draw steadily, which is why a range is more honest than one fixed answer.

Why a bigger battery capacity does not always last longer

A large mAh figure is only one side of the sum. The other side is how hungry the phone is. Four things matter most.

• Screen: size, brightness and refresh rate. A high refresh rate costs charge even when you only scroll.
• Processor and software: a busy chip with heavy background apps uses more than a quiet one.
• Network: poor reception forces the radio to work harder, draining the battery fast.
• Heat and age: a hot phone loses charge faster, and an old cell holds less than its label says.

Charging time follows a different rule: it depends on the charging watts and the charger in use, not on mAh alone. If your phone is losing charge fast, read the page on fast drain causes before you blame the pack. To measure the pack itself, learn how to check your battery health.

Where to read the capacity of battery on your phone

There is no single place that works for every phone. The surest sources are the maker's specification page for your exact model number and the label on the battery. Many Android phones show battery details in Settings, but menu names differ by brand and version, so searching the word battery beats following a fixed path. Samsung keeps owner help and model information at its support site for India.

A health figure in percent is not the same as capacity. It compares the current pack with its new state. A phone that shows 85 percent health on a 5000 mAh pack holds somewhat less than 5000 mAh now.

Use the steps on this page to find the exact phone first. Without the right model number, any capacity you read may belong to a sibling phone with a different pack.

All capacity pages in this group

Each page below handles one question about capacity. The mAh class pages explain what a size means for daily use. The phone pages give the figure for that phone and say clearly what is confirmed. Launch details can change, so each phone page is the place to read the latest status.

If your question is about a code printed on a battery, or about a phone's replacement pack, you want a different set of pages. The big one is the battery model name guide, which leads to every code family. Start with the Xiaomi group code list, and large battery phones are gathered on our biggest battery page.

Capacity and battery codes: two different questions

Capacity tells you how much a pack stores. A code tells you which pack it is. Two batteries can show the same mAh and still be different parts, with another connector, another size or another voltage. That is why the code, and not the mAh, decides what fits your phone.

Code families give a hint about the maker group. Xiaomi, Redmi and POCO use codes starting with BN, BM or BP. Oppo, Realme and OnePlus use BLP codes. vivo and iQOO codes are short: B, a hyphen and two characters. Samsung uses EB-B codes and some other supplier codes, and Motorola uses two letters and two digits. A family only names the maker group, never the exact phone.

For the exact phone list, open the page for that code. Oppo, Realme and OnePlus owners can start from the BLP code family page, Vivo and iQOO owners from the Vivo and iQOO code family page, and Samsung and Motorola owners from the Samsung and Motorola code family page.

Fake capacity labels and safe replacement

A weak pack with a printed number far above what its size can hold is a common problem. A real cell cannot store more than its volume allows, so a small pack claiming a very large mAh is false. Watch for low weight, smudged print, missing batch details and a number far above the original.

Sealed phones should have the battery changed at the brand's own service centre or by a repair shop you trust. Confirm the cell code, the handset model number and the connector all match. Fitting advice is in the replacement and fitting tips.