Most people buy a power bank the same way. They look at the mAh number, pick the biggest one they can afford, and assume bigger always means better.
That instinct costs money. It also leaves plenty of shoppers carrying a heavy brick when a slim unit would have done the job perfectly. So let's work out what capacity you genuinely need.
Capacity Is Not the Whole Story
Capacity tells you how much energy a power bank stores. Manufacturers print it in milliampere-hours, which is where 10000mAh and 20000mAh come from.
However, that number alone cannot tell you how useful a power bank will be. Two units with identical capacity can behave very differently, because output speed, port types and weight all shape the daily experience.
So the best power bank for you is rarely the largest one on the shelf. It is the one you actually carry every day, charged and ready, without resenting the weight in your bag.
What mAh Actually Means
Understanding this section saves you from the single biggest disappointment in the category. Almost every buyer hits it eventually.
Once you know the rule below, product listings suddenly make sense. You will also spot dishonest capacity claims quickly.
Rated Capacity Versus Usable Capacity
A power bank stores energy at roughly 3.7 volts. Your phone charges at 5 volts. Converting between the two loses energy as heat, and that loss is unavoidable physics rather than a manufacturing flaw.
As a result, you receive roughly 60% to 70% of the printed number. A 10000mAh power bank typically delivers around 6,000mAh to 7,000mAh into your phone. Honest brands acknowledge this openly.
Spotting Inflated Claims
Unbranded units routinely overstate capacity. A cheap "20000mAh" bank from an unknown seller may hold barely half that in reality.
Weight offers a useful clue. Genuine cells have mass, so a suspiciously light 20000mAh unit deserves suspicion. Buying from a brand with a real warranty removes the guesswork entirely.
How Many Charges Will You Actually Get?
Now apply the maths to real phones. Most current smartphones carry batteries between 4,000mAh and 5,000mAh.
Take a 10000mAh power bank with roughly 6,500mAh usable. That gives you slightly more than one full charge for a modern flagship, or two charges for a smaller phone.
Step up to 20000mAh and usable capacity lands near 13,000mAh. Consequently, you get two to three full charges, which comfortably covers a weekend away or a long day of load shedding.
Matching Capacity to Your Actual Routine
Forget the specs for a moment. Think about your day instead, because your routine determines the best power bank for you far more reliably than any comparison chart.
Below are the three patterns that cover most buyers in Pakistan. Find yours, then buy accordingly.
The Daily Commuter
You leave home charged and return the same evening. You need one top-up, not three.
A 10000mAh unit fits this perfectly. It slips into a pocket or handbag, weighs little, and recharges overnight. Anything larger simply adds weight you carry for no reason.
The Traveller and Long-Route User
You take intercity trips, sit in airports, or spend hours on the motorway. Wall sockets appear rarely and unpredictably.
Here 20000mAh earns its place. You get multiple charges, and you can share power with a travelling companion without running dry before you arrive.
The Heavy User and Multi-Device Owner
You carry a phone plus earbuds, a smartwatch, or a tablet. Load shedding also stretches your requirements at home.
Choose 20000mAh or higher, and prioritise multiple output ports. Charging three devices from one bank matters more than shaving off a few grams.
Output Speed Matters as Much as Capacity
Capacity decides how long a power bank lasts. Output decides how fast it works. Buyers who ignore the second number often regret it.
A 10000mAh unit with basic 5V/2.1A output charges a phone in roughly four hours. The same capacity with 22.5W fast charging does the job in well under two. Same size, very different experience.
Therefore, check the output rating alongside the capacity figure. Look for Power Delivery and Quick Charge support if you own an iPhone or a modern Android device. Our post on phone charging slowly explains what else throttles charging speed.
Weight, Ports and Travel Rules
Capacity adds weight. A 10000mAh bank usually sits around 200 grams, while 20000mAh models roughly double that. You feel that difference by the end of a long day.
Ports deserve thought too. Built-in cables suit people who forget accessories, while dual output ports suit households sharing one bank. Pick based on habit rather than specification sheets.
One practical rule matters for flights. Airlines generally cap power banks at 100Wh, which works out around 27,000mAh. So 10000mAh and 20000mAh units travel without issue, but always keep them in your cabin bag rather than checked luggage.
Choosing Your Interlink Power Bank
Interlink covers every capacity tier, so match the model to the routine you identified above. Each unit carries an official 6-month warranty.
For daily commuters, the AXE 10000mAh (Rs. 2,400) and ECO 10000mAh (Rs. 2,500) deliver dependable dual-USB backup at the lowest cost. The Reco Plus 10000mAh (Rs. 2,700) adds three built-in cables covering Lightning, Type-C and Micro USB, which suits anyone who keeps losing wires.
If speed matters more than price, the Aero 10000mAh (Rs. 4,800) and Raiz 10000mAh (Rs. 4,700) both offer 22.5W with PD and QC 3.0 in a genuinely pocketable size. For travellers and heavy users, the Boost Plus 20000mAh (Rs. 5,200) pairs high capacity with 22.5W fast charging and multi-voltage output.
Browse the full range on the power bank . Interlink delivers free across Pakistan with cash on delivery, so you can find the best power bank for your routine without leaving home.
Frequently Asked Questions
Why does my 10000mAh power bank not fully charge my phone twice?
Because roughly 30% to 40% of rated capacity is lost during voltage conversion. A 10000mAh unit typically delivers 6,000mAh to 7,000mAh, which suits one full charge on a modern flagship.
Is 20000mAh better than 10000mAh?
Only if you need it. The best power bank for daily commuting is usually 10000mAh, since it weighs half as much. Choose 20000mAh for travel, multiple devices, or long outages.
Can I take a power bank on a flight?
Yes, within limits. Airlines generally allow units up to 100Wh, roughly 27,000mAh. Carry it in your hand luggage, never in checked baggage.
Does a bigger power bank charge my phone faster?
No. Speed comes from output wattage, not capacity. A 22.5W unit charges far faster than a basic 5V model of identical size.
Final Thoughts
Choosing capacity comes down to honest self-assessment. Count the charges you actually need in a normal day, then add a small margin.
Most people land on 10000mAh and stay happy. Travellers and heavy users step up to 20000mAh. Either way, check the output wattage before you buy, because a power bank you never bother carrying helps nobody.