More exciting mobile apps than ever mean more rapidly draining phones than ever. Smartphones and tablets do wonders to keep us entertained and connected on long days far from outlets, but they’re pretty useless if they run out of battery. Enter portable chargers.

Portable chargers — aka power banks, aka battery packs — range from credit-card-thin rectangles that will give your phone a small emergency boost to heavy-duty models that will charge every device in your arsenal multiple times, but stretch the meaning of the word portable. Because of the inevitable trade-off between size and capacity when it comes to power banks, it’s important to consider what you’ll actually be using the device for. Below, we’ve broken down three top portable chargers across the spectrum to help you choose one that’s right for your needs.

There are a few basics to keep in mind when selecting a portable charger: how fast it can charge your device, how many times it can charge it, how long the power bank itself takes to charge, how many devices it can charge at once, and, most important, how portable — lightweight and sleek — the charger actually is.

You’ll also note some potentially confusing letters and numbers when shopping for a portable charger. Briefly, milliamp hours, or mAh, refer to the charger’s capacity; a higher mAh roughly means a charger should refuel your device more times. Numbers like .5A, 1A, or 2A, meanwhile, essentially boil down to how fast the battery will charge your device (the “A” is for amperage, which is a measure of the electric current flowing through the charger). Good power banks should have an output of at least 1A to charge smartphones and 2A for anything larger.

Portable chargers also often come with an included micro USB cable; iPhone users should use the lightning cable that came with their phone. While you may be enticed by the convenience of power banks with preattached cables — since this means one less thing to carry — some reviewers point out that these cables tend to be flimsy and awkward in actual use.

Best all around portable charger: Anker PowerCore II 10000 mAh ($35.99;

An upgrade from the company’s wildly popular PowerCore 10000, Anker’s PowerCore II has everything that made its predecessor earn nearly 8,000 5-star reviews and then some. Reliable, lightweight and affordable, this is an excellent choice for everyday use. Anker is known for producing sleek, quality battery packs and has struck a near perfect balance between power and portability with the PowerCore II 10000, which Anker says is “only slightly heavier than a baseball” (6.4 ounces, to be exact) and compact enough to slip into a pocket or purse.

Anker promises the PowerCore II 10000 will charge most phones about three times before it needs recharging itself (as with all power banks, the exact number of charges varies per device); you should also be able to get at least one full charge of a tablet. Eight blue LEDs, an upgrade from four on the previous model, tell you how much juice the charger itself has left. In another upgrade from the previous version, this model is compatible with Qualcomm Quick Charge 3.0 devices. As with most Anker chargers, the PowerCore II 10000 comes with a micro USB cable, convenient travel pouch, and 18-month warranty. Those with Apple devices will need to use the lightning cable that came with their phones.

Do note that this model has a single USB charging port, meaning you can only charge one device at a time. That said, the PowerCore II 10000 is a great choice that will meet most people’s needs without weighing them down. As one reviewer notes, “It holds a huge charge and is tiny. What more would anyone want?”

Best ultra-lightweight portable charger: Anker PowerCore+ Mini 3350 mAh (starting at $19.99;

With nearly 19,000 5-star reviews, the PowerCore+ Mini is another winner from Anker and perfect for those times when you want to be carrying as little as possible. The “original lipstick-shaped power bank” weighs a mere 2.8 ounces and can be fully recharged in just three to four hours — meaning you don’t have to sit around forever waiting for it to be ready to go. With blue, silver, gold and pink options in addition to basic black, it’s also more colorful than most tech accessories.

True, it can only charge your mobile device about once (and for higher-powered phones, it’s really just a top-off). As with the Anker model above, a single port also means you can only charge one device at a time. Still, the sheer convenience of the Mini 3350 might make this the charger you end up reaching for most, simply because it ticks off that most important element of a portable charger: portability. It’s tiny, sturdy and inexpensive, making it a no-brainer to toss it in your bag and forget about it until you need it.

Best high-powered portable charger: Anker PowerCore+ 26800 mAh 30W Power Delivery ($129.99;

It’s clear that Anker is producing some of the best power banks around. This workhorse is decidedly heavier than either of the previous models, but the PowerCore+ 26800 makes up for its weight in a big way. For one thing, it will charge three devices at once — and with 30W Power Delivery (a fast-charging technology), it’ll do it quickly. The inclusion of USB-C connection — the kind used by Macbooks and Google Pixel phones — means the PowerCore+ 26800 is compatible with nearly all Apple and Android devices. Most impressively, its super-high capacity will charge a laptop at least once and most phones a whopping seven to eight times. That means a full week without worrying about being tethered to an outlet. It also comes with a USB-C wall charger that’s used to power up the battery itself — something it accomplishes in a pretty spectacular 4.5 hours.

Of course, at 1.27 pounds, this definitely is not the kind of charger you’ll want (or really be able) to toss in your pocket. But there are times when the added weight is worth it — when you’re hunkering down to work in a coffee shop and don’t feel like duking it out for an outlet, heading on an extra-long flight or bus ride, or are going to be off the grid for a few days (because even if you’re taking a social media break, you’ll want to be able to take pictures and use a map). You can also keep this heavier charger in your suitcase or backpack and toss either of the lighter options above into a purse or daypack for more active excursions.

Best everything charger: Maxoak Laptop Power Bank 50,000mAh ($129.99;