PhoneLifespan

Spark 40 5G vs Redmi 15 5G

vs

Winner

Xiaomi Redmi 15 5G

Lifespan decides this one: the Redmi 15 5G is supported until Aug 2029 at $4.80 per month of safe use, while the Spark 40 5G runs out in Aug 2028 ($4.40/month). On a which-lasts-longer question, that's not a tie — it's the whole answer.

Value Score: Spark 40 5G 72 · Redmi 15 5G 75 — methodology

The lifespan decider

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

Tecno Spark 40 5G $115
Buy with care$4.40/mo
2025◆ Buy-by Aug 20262028
Xiaomi Redmi 15 5G $180
Safe to buy$4.80/mo
2025◆ Buy-by Aug 20272029

Category by category

Display
Spark 40 5G 70Redmi 15 5G 70

Both displays are effectively the same class.

Performance
Spark 40 5G 55Redmi 15 5G 46

The Spark 40 5G's MediaTek Dimensity 6400 is simply the faster chip.

Camera
Spark 40 5G 55Redmi 15 5G 55

Camera systems are comparable on paper — pick by sample photos.

Battery
Spark 40 5G 100Redmi 15 5G 100

Battery capacities are close enough not to decide this.

Software longevity
Spark 40 5G 31Redmi 15 5G 45

The Redmi 15 5G is supported until Aug 2029 — 11 months longer than the Spark 40 5G.

Value
Spark 40 5G 72Redmi 15 5G 75

Pound for pound, these two are equally good deals.

Full spec table
SpecSpark 40 5GRedmi 15 5G
Price (street)$115$180
Display6.75-inch IPS LCD, HD+, 120Hz6.9-inch IPS LCD, FHD+, 144Hz, 850 nits peak
ChipsetMediaTek Dimensity 6400Qualcomm Snapdragon 6s Gen 3
RAM4GB/8GB4GB/6GB/8GB
Storage128GB/256GB128GB/256GB
Battery6,000 mAh7,000 mAh
Charging18W wired33W wired, 18W reverse wired
Rear cameras50MP main50MP main, 2MP depth
Dimensions167.7 × 77.9 × 8 mm169.5 × 80.5 × 8.4 mm
Weight194 g217 g
Water resistanceNot ratedIP64
Supported untilAug 2028Aug 2029
Spark 40 5G full verdict →Redmi 15 5G 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.