Work Out How Many Phone Charges a Power Bank Gives in Pakistan
Printed mAh is not what reaches your phone. Our estimate is 60 to 70 percent, so 10,000 mAh charges a 5,000 mAh phone about once. Sums, Wh formula, fake checks.
Short answer: A power bank gives about 60 to 70 percent of its printed mAh as usable charge. So a 10,000 mAh power bank charges a 5,000 mAh phone about once to one and a half times, not twice. This is our own estimate from the usual loss in voltage conversion, not a fixed rule.
A shop in Lahore sells a 20,000 mAh power bank, and the buyer expects four full charges for a 5,000 mAh phone. He gets two and a half. The label is not a lie. The number measures the battery inside, and some of that energy is lost when it is boosted to charge your phone.
This page is a method, not a news report. The sums are simple physics and our own working. We did not lab-test a power bank for this guide. Where we use a rule of thumb, we say so.
The printed mAh is not the charge you receive
The mAh on the box counts the cells inside the power bank at about 3.7 volts. A phone charger works at 5 volts or more. The power bank must raise the voltage, and that conversion wastes some energy as heat. So you get less than the box number.
A common rule of thumb is that 60 to 70 percent of the printed capacity reaches your phone. The exact share depends on the power bank, the cable and how fast you charge. Fast charging and cheap cables lose more. Treat the range as an estimate.
- Find the printed capacity in mAh on the power bank.
- Multiply it by 0.6 for a cautious figure, and by 0.7 for a good one.
- Find your phone's battery size in mAh in its settings or specifications.
- Divide the usable figure by the phone's battery size.
Work it out with real examples
The sums below use a 5,000 mAh phone, which is common in Pakistan. A larger phone battery gives fewer charges. Write down your own phone's number and change the sum. The results are estimates at 60 to 70 percent.
| Power bank (printed) | Usable at 60 to 70 percent | Charges for a 5,000 mAh phone |
|---|---|---|
| 10,000 mAh | 6,000 to 7,000 mAh | About 1.2 to 1.4 |
| 20,000 mAh | 12,000 to 14,000 mAh | About 2.4 to 2.8 |
| 30,000 mAh | 18,000 to 21,000 mAh | About 3.6 to 4.2 |
For an iPhone or a phone with a small battery of 3,500 to 4,000 mAh, the same power bank gives more charges. If your phone has a very large battery, the count falls.
Convert mAh to watt-hours
Watt-hours (Wh) measure energy and do not depend on voltage. The formula is mAh multiplied by 3.7, divided by 1,000. A 10,000 mAh cell at 3.7 volts holds 37 Wh. This is the number airlines use, so it is worth knowing.
The same formula for a 20,000 mAh power bank gives 74 Wh, and for 30,000 mAh gives 111 Wh. Many power banks print Wh on the case already. If yours does not, use the sum. For the airline limits and what to carry in your hand luggage, read the guide to power bank rules on flights from Pakistan. We did not re-check those airline limits for this page.
Check that you are not buying a fake rating
Some cheap power banks print a capacity the cells cannot hold. A small, light 20,000 mAh power bank at a very low price is a warning sign. Real cells have weight, and a bank that weighs the same as a 5,000 mAh one is suspect.
- Compare the weight with a known brand of the same stated capacity.
- Look for the Wh figure on the case. If only mAh is printed, be careful.
- Charge your phone from 0 to 100 percent and see how much of the power bank is used.
- Buy from a shop that gives a written warranty and a receipt.
The same caution applies to chargers and cables. See how to check if your phone charger or cable is fake. For a list of models, see best power banks in Pakistan, but check the current price at the shop.
Use it safely
A power bank holds a lithium battery. Do not use one that is swollen, hot to touch or damaged. Do not charge it under a pillow, and do not leave it in a hot car. These are common-sense steps, not a quote from a rule.
If a phone gets very hot while charging, stop and read how to stop your phone overheating while charging. If a battery looks swollen, stop using it and follow what to do about a swollen battery. Slow charging problems are covered in fixing a phone that charges slowly.
Common questions
Why does my 10,000 mAh power bank not charge my phone twice?
Some energy is lost as heat when the power bank raises the voltage. Our estimate is that 60 to 70 percent of the printed capacity reaches the phone, so a 5,000 mAh phone gets about one to one and a half charges.
How do I convert mAh to Wh?
Multiply mAh by 3.7 and divide by 1,000. A 10,000 mAh power bank is 37 Wh. This assumes the usual 3.7 volt cells.
Is a bigger power bank always better?
No. A bigger one weighs more, takes longer to charge and is harder to carry on a flight. Choose by how many charges you need in a day.
Does fast charging use more of the power bank?
It can. Faster charging and poor cables often lose more energy as heat, so the number of charges can fall. We did not measure this.
Can I trust the mAh printed on cheap power banks?
Not always. Check the weight, look for a Wh label, and buy from a shop that gives a receipt and warranty. A very low price for a very high number is a warning sign.
How we verified this
What we checked, where we read it, and what we could not confirm.
Last checked on 13 October 2026, Pakistan time. This page is based on our own arithmetic using the standard 3.7 volt cell rating, and a commonly quoted loss of 30 to 40 percent in conversion, which we present as an estimate. We did not test any power bank in a lab, and we did not read a maker's page for a specific model. Check airline limits with your airline before you fly.
About the author
Technology Journalist & Multimedia Producer
Ahmad Ali is a technology journalist and multimedia producer at Pakistan Era, joining the team in October 2026. He covers consumer technology and digital life for Pakistani readers, combining research with hands-on product testing.
