The mAh on the box is not what you get.

A power bank loses about a third of its rated capacity to voltage conversion, so a 20,000mAh brick really delivers around 48Wh. This ranks by cost per usable Wh, the honest number, with the fast charge output and weight beside it. Sort for value, filter for laptop charging, done.

Prices reviewed 31 July 2026 . Charger prices swing on sales, so check the live listing before buying.

Need serious backup instead? See the power station and solar panel rankings.

Brand

Capacity

Output

Max price

Currency

Power bank	Rated mAh	Usable Wh	Max output	Weight	Price	$/usable Wh
JOYROOM 20K 22WBest value	20,000	48 Wh	22 W	12 oz	$28	$0.58	Check price
Baseus 20K 22W	20,000	48 Wh	22 W	12 oz	$30	$0.62	Check price
Xiaomi 20K 22W	20,000	48 Wh	22 W	15 oz	$30	$0.62	Check price
INIU Slim 10K	10,000	24 Wh	15 W	6.9 oz	$18	$0.75	Check price
INIU 25K 45W	25,000	60 Wh	45 W	15 oz	$45	$0.75	Check price
Baseus 30K 65W	30,000	72 Wh	65 W	19 oz	$55	$0.76	Check price
INIU 20K 45W	20,000	48 Wh	45 W	12 oz	$37	$0.77	Check price
INIU 10K 22W	10,000	24 Wh	22 W	7.4 oz	$20	$0.83	Check price
INIU 27K 65W	27,000	65 Wh	65 W	17 oz	$55	$0.85	Check price
Anker 337 26K 20W	26,800	64 Wh	20 W	17 oz	$55	$0.85	Check price
Anker 313 10K	10,000	24 Wh	12 W	7.5 oz	$22	$0.91	Check price
Anker 525 20K 25W	20,000	48 Wh	25 W	12.5 oz	$45	$0.94	Check price
RAVPower 20K 60W	20,000	48 Wh	60 W	12.5 oz	$45	$0.94	Check price
Samsung 20K 25W	20,000	48 Wh	25 W	12.5 oz	$45	$0.94	Check price
Belkin 20K 30W	20,000	48 Wh	30 W	13 oz	$50	$1.04	Check price
Anker 523 10K 22W	10,000	24 Wh	22 W	7.7 oz	$26	$1.08	Check price
UGREEN 10K 30W	10,000	24 Wh	30 W	7.8 oz	$28	$1.16	Check price
Anker Nano 10K 30W	10,000	24 Wh	30 W	7.5 oz	$30	$1.25	Check price
Anker Laptop 20K 87W	20,000	48 Wh	87 W	12.9 oz	$60	$1.25	Check price
Baseus Blade HD 20K 100W	20,000	48 Wh	100 W	14.6 oz	$60	$1.25	Check price
Baseus 10K 30W	10,000	24 Wh	30 W	7.6 oz	$30	$1.25	Check price
Mophie Powerstation 20K	20,000	48 Wh	20 W	13 oz	$60	$1.25	Check price
Baseus Magnetic 10K	10,000	24 Wh	20 W	8.3 oz	$35	$1.46	Check price
Ampace 20K 100W	20,000	48 Wh	100 W	14 oz	$70	$1.46	Check price
Zendure SuperTank 27K 100W	27,000	65 Wh	100 W	20 oz	$100	$1.54	Check price
UGREEN 12K Magnetic	12,000	29 Wh	20 W	9 oz	$45	$1.56	Check price
Goal Zero Flip 36	10,050	24 Wh	18 W	7.4 oz	$40	$1.65	Check price
UGREEN Magnetic 10K	10,000	24 Wh	20 W	8.5 oz	$40	$1.66	Check price
Cuktech 10 Ultra 20K 165W	20,000	48 Wh	165 W	15 oz	$80	$1.66	Check price
Sharge 25K 100W	25,000	60 Wh	100 W	18 oz	$100	$1.66	Check price
Anker 737 24K 140W	24,000	58 Wh	140 W	22.9 oz	$100	$1.73	Check price
UGREEN Nexode 20K 145W	20,000	48 Wh	145 W	16.8 oz	$90	$1.87	Check price
CUKTECH 20K 210W	20,000	48 Wh	210 W	16 oz	$90	$1.87	Check price
Torras Magnetic 10K	10,000	24 Wh	20 W	8 oz	$45	$1.87	Check price
Elecjet Apollo 10K 65W	10,000	24 Wh	65 W	9 oz	$45	$1.87	Check price
Anker Prime 27K 250W	27,650	66 Wh	250 W	22.9 oz	$130	$1.95	Check price
UGREEN Nexode 25K 200W	25,000	60 Wh	200 W	21 oz	$120	$2	Check price
Anker Prime 20K 200W	20,000	48 Wh	200 W	18.6 oz	$100	$2.08	Check price
Anker MagGo 10K Qi2	10,000	24 Wh	15 W	7.9 oz	$60	$2.49	Check price
Nitecore NB10000 Gen3	10,000	24 Wh	18 W	5.3 oz	$60	$2.49	Check price

How the ranking works. The headline metric is dollars per usable Wh, which is the honest value number. The rated mAh is measured at the cell voltage of 3.7V, but charging your devices loses roughly a third of that to conversion, so we compute the real delivered energy (about 65 percent of the paper figure) and divide the price by it. We also show the max output in watts, which decides whether it can fast charge a phone (20W+), a thin laptop (65W+) or a big laptop (100W+), plus the weight for travel. Sort by dollars per usable Wh for raw value, or filter by output if you need to charge a laptop. Prices are USD, converted live to your currency, and reviewed regularly.

Common questions

Why does it not charge my phone the full number of times?

The mAh is rated at 3.7V, but your phone charges at 5V or more and conversion loses energy as heat. You get about 60 to 70 percent out, so a 20,000mAh bank delivers roughly 48Wh. We show that real figure.

What size do I need?

10,000mAh gives a phone ~2 charges and stays pocketable. 20,000mAh covers phone plus tablet or a long trip. For a laptop, 20,000mAh+ with 65W+ output, 100W for a big laptop.

Can it charge a laptop?

Yes with enough capacity and a fast USB-C PD output. 20,000mAh+ and 65W for a thin laptop, 100W+ for full size. Filter by high output.

Best value power bank?

On $/usable Wh, plain 20,000mAh banks from value brands like INIU and Baseus are hard to beat, often half the cost per Wh of a premium unit. You pay extra for fast charge, magnetic wireless, a screen or slimness.