iPhone Duo storage: which size should you buy?
Choose 256GB if your photos sync to iCloud and you stream your media, 512GB if you keep photos and video on the phone or are unsure (storage cannot be added later), and 1TB or 2TB only if you already fill 512GB.
VoltVault has the iPhone Duo in stock in 256GB ($1,899 USD), 512GB ($2,099 USD), 1TB ($2,499 USD) and 2TB ($3,099 USD), open-box and never used, shipped from Utah, USA within 2 business days of confirmed payment with a 30-day money-back guarantee.
See the iPhone Duo (512GB) — $2,099 →
Every size is the same phone: the Apple A20 Pro chip, a 48MP dual camera, a titanium frame and the 7.6-inch folding inner and 5.4-inch outer displays, as listed on the product pages. Only the storage and the price change, so the choice is how much room you need.
The four sizes
| iPhone Duo 256GB | $1,899 USD · the smallest size · listed in stock Enough if your photos sync to iCloud and you stream your music and video. Plan to clear large downloads now and then. |
|---|---|
| iPhone Duo 512GB | $2,099 USD · $200 more than 256GB · listed in stock Our pick if you are unsure: room for years of photos, plenty of video, several large games and some media kept offline. |
| iPhone Duo 1TB | $2,499 USD · $400 more than 512GB · listed in stock For a large photo and video library kept on the phone, long clips every week, or offline work with big files. |
| iPhone Duo 2TB | $3,099 USD · $600 more than 1TB · listed in stock The largest size we list. Worth it only if you have already outgrown 1TB or the phone is your only computer. |
Manufacturer image shown for reference; not a photo of the individual item.
Check your own need in three steps
1. See what you use now. On your current iPhone open Settings → General → iPhone Storage. The number at the top is what your phone holds today, and photos, videos and apps are usually the biggest bars.
2. Leave room to grow. Add what you expect to add over the years you will keep the phone, and keep roughly a fifth of the storage free (a rule of thumb, not an Apple requirement) so updates and new photos never run you out of space. Then pick the smallest size that covers the total.
3. Remember the system takes some. Apple says a standard configuration uses approximately 12GB to 24GB of space, including iOS and Apple apps that can be deleted, and that Apple Intelligence on-device models use approximately 7GB (Apple's iPhone Duo page, read October 26, 2026). The space you can use is a little less than the number on the box.
The same terms on every size
US model, eSIM only (no physical SIM tray). Works on carriers that support eSIM; check yours before buying. The box holds the phone and a USB-C cable, with no power adapter. It has been opened, so we do not sell it as factory-sealed.
Your phone leaves Utah, USA within 2 business days of confirmed payment, with free tracked shipping. Inside the US it then typically takes about 2–5 business days; times are estimates, not guarantees. Apple's own wait is on our iPhone Duo delivery date page.
Not right for you? The 30-day money-back guarantee covers any reason, including changing your mind. If you simply change your mind you cover the return postage.
More iPhone Duo guides
- iPhone Duo in stock, open-box and never used
- Where to buy iPhone Duo: compare storage, condition and delivery
- Which iPhone Duo color to buy: Star White or Night Sky
- What comes in the box with an iPhone Duo
- US iPhone Duo abroad: eSIM only, check your carrier first
- Is VoltVault legit?
See the iPhone Duo (512GB) — $2,099 →
Common questions
Is 256GB enough for the iPhone Duo?
It is if your photos and videos sync to iCloud and you stream your music and shows. As a rule of thumb, if your current iPhone uses under about 150GB in Settings → General → iPhone Storage and that is not about to jump, 256GB is enough. If you shoot a lot of video, keep media offline or install several large games, 512GB is the safer size.
Which iPhone Duo storage size should I buy?
It depends on how you use the phone. If your photos live in iCloud and you stream your media, 256GB is enough. If you keep photos, video and games on the phone, or you are not sure, 512GB is our pick: at VoltVault's prices it costs $200 more than 256GB, gives you twice the room, and the storage cannot be added later. Choose 1TB or 2TB only if you already fill 512GB.
Can I add storage to an iPhone Duo later?
No. The storage is fixed when you buy, so buy for the years you plan to keep the phone. iCloud can hold photos and files you don't need on the phone, but it does not add space to the phone itself.
How much more does each iPhone Duo size cost?
At VoltVault's prices, 512GB is $200 more than 256GB, 1TB is $400 more than 512GB, and 2TB is $600 more than 1TB. Prices come from the same catalog as the product pages.
Is the 2TB iPhone Duo worth it?
For most buyers, no. At our prices it costs $600 more than the 1TB, and it only pays off if you have already outgrown 1TB or use the phone as your only computer. Check Settings → General → iPhone Storage on your current phone first.
Do all four iPhone Duo sizes have the same screen and cameras?
On our product pages they do. Every size lists the Apple A20 Pro chip, a 48MP dual camera, a titanium frame and the 7.6-inch folding inner and 5.4-inch outer displays. Only the storage and the price change.