X100 Ultra vs 15

Phone 1

Phone 2

Winner

Xiaomi 15

Lifespan decides this one: the 15 is supported until Mar 2030 at $16.88 per month of safe use, while the X100 Ultra runs out in May 2029 ($20.39/month). On a which-lasts-longer question, that's not a tie — it's the whole answer.

Value Score: X100 Ultra 66 · 15 67 — methodology

The lifespan decider

When specs are close, support length decides it — this is what each phone costs per month of safe use.

Vivo X100 Ultra $720

Buy with care$20.39/mo

2024◆ Buy-by May 20272029

Xiaomi 15 $750

Safe to buy$16.88/mo

2025◆ Buy-by Mar 20282030

Category by category

Display

X100 Ultra 9015 90

Both displays are effectively the same class.

Performance

X100 Ultra 9215 98

The 15's Snapdragon 8 Elite is simply the faster chip.

Camera

X100 Ultra 8415 79

The X100 Ultra has the stronger camera system — same lens count, higher-grade sensors.

Battery

X100 Ultra 9015 85

5,500mAh vs 5,240mAh — the X100 Ultra lasts longer between charges.

Software longevity

X100 Ultra 4215 53

The 15 is supported until Mar 2030 — 9 months longer than the X100 Ultra.

Value

X100 Ultra 6615 67

Pound for pound, these two are equally good deals.

Full spec table

Spec	X100 Ultra	15
Price (street)	$720	$750
Display	6.78-inch LTPO AMOLED, 120Hz, 3000 nits peak	6.36-inch CrystalRes AMOLED, 2670×1200 (460 ppi), 1–120Hz LTPO, up to 3200 nits peak, Dolby Vision/HDR10+
Chipset	Snapdragon 8 Gen 3	Snapdragon 8 Elite
RAM	12GB/16GB	12GB
Storage	256GB/512GB/1TB	256GB/512GB
Battery	5,500 mAh	5,240 mAh
Charging	80W wired, 30W wireless	90W wired, 50W wireless
Rear cameras	50MP main, 200MP periscope telephoto, 50MP ultra-wide	50MP main (Light Fusion 900, f/1.62), 50MP ultra-wide, 50MP telephoto (Leica 60mm floating)
Dimensions	164.1 x 75.6 x 9.2 mm	152.3 × 71.2 × 8.08 mm
Weight	229 g	191 g
Water resistance	IP68/IP69	IP68
Supported until	May 2029	Mar 2030

X100 Ultra full verdict →15 full verdict →Longevity master board →

Scores and verdicts are computed from our verified database — see exactly how. Specs from manufacturer documentation; prices reflect major US retailers.