Creator Gear

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Rule of thumb: consumer 4K video eats roughly 30 GB per hour at common bitrates — so an hour of 4K needs about six times the space of the same hour at 1080p. Use the calculator below to size your storage for photos and video together.

Storage per hour by resolution

High-frame-rate, high-bitrate, or professional (log/RAW) footage can be several times larger, so treat these as consumer baselines.

What capacity should you buy?

Where to store it

• microSD / SD — in-camera capture. See how many photos 128GB holds.
• Portable SSD — fast offload and editing on the go.
• External HDD / NAS — cheap bulk archiving.

Size it precisely with our Digital Storage Calculator, then compare portable SSDs and high-speed SD cards on Amazon.

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Short answer: a 128 GB card holds roughly 25,000 JPEG photos from a typical smartphone or mid-range camera (around 5 MB each). Shoot in RAW and that drops to about 4,000–5,000. Use the calculator below for your exact file sizes.

Photos per 128 GB by file size

Usable space is a little lower than the label (formatting overhead), so treat these as close estimates.

Don’t forget video

If you also shoot 4K video, storage disappears fast — about 30 GB per hour. See how much storage you need for 4K video.

Work out a mixed photo-and-video total with our Storage Calculator, then browse 128GB cards on Amazon.

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The right power bank size depends on what you’re charging and how long you’ll be away from an outlet. Here’s a simple way to choose without overpaying for capacity you’ll never use.

Match capacity to your need

Don’t just look at mAh

• Output wattage (USB-C PD): to fast-charge a phone you want 20 W+; for laptops, 60–100 W.
• Real charges are lower than the label — expect roughly 70–85% efficiency. Our Power Bank Calculator shows the realistic number for your device.
• Air travel: stay under 100 Wh (about 27,000 mAh) to avoid airline approval. See power banks on a plane.

Once you know your target capacity, browse current options: See Power Banks on Amazon.

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Short answer: A 20,000 mAh power bank realistically recharges a typical smartphone 3 to 5 times — not the 6+ the raw numbers suggest. That’s because of conversion losses. Use the calculator below to get a number for your exact phone.

Why you don’t get the full capacity

Power banks store energy at 3.7 V but charge your phone at 5 V or higher. Converting voltage loses energy as heat, so real-world output is typically 60–85% of the label. Fast charging, a warm battery, and cable quality all reduce it further.

The math

Charges = (power bank mAh × efficiency) ÷ phone battery mAh.

For a 20,000 mAh bank at 80% efficiency charging a 3,200 mAh phone: (20,000 × 0.8) ÷ 3,200 = 5 full charges. A phone with a bigger 5,000 mAh battery would get about 3.2 charges from the same bank.

Real-world examples

Flying with it? A 20,000 mAh bank is about 74 Wh, so it’s fine in carry-on — see can you take a power bank on a plane.

Ready to buy? Compare Power Banks on Amazon.

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Short answer: Yes — but a power bank must go in your carry-on bag, never checked luggage, because it contains a lithium-ion battery. Most consumer power banks are allowed without special approval, and the deciding factor is the battery’s watt-hour (Wh) rating, not its size.

The watt-hour rules (US TSA/FAA and most airlines)

• Under 100 Wh — allowed in carry-on, generally no airline approval needed. This covers almost every phone-charging power bank.
• 100–160 Wh — allowed with airline approval, usually a maximum of two spares.
• Over 160 Wh — not permitted on passenger aircraft.

How to convert mAh to Wh

Power banks are labelled in mAh, but airlines care about Wh. The formula is:

Wh = (mAh ÷ 1000) × battery voltage (lithium cells are 3.7 V).

So a common 20,000 mAh power bank is (20 × 3.7) = 74 Wh — comfortably under the 100 Wh limit. Even a large 26,800 mAh bank is about 99 Wh, still under the cap. Many power banks now print the Wh rating on the case.

Quick reference

Practical tips

• Keep power banks in your carry-on and, ideally, in a pouch so the terminals can’t short against keys or coins.
• Rules are set by aviation authorities and individual airlines and can change — confirm with your airline and the TSA/your national authority before flying, especially for international trips.
• Not sure how many charges your bank actually delivers on a trip? Use our Power Bank Calculator to plan.

Shopping for a travel-friendly bank under 100 Wh? See current options: Browse Power Banks on Amazon.