Both have Super AMOLED FHD+ and a 5000 mAh battery. The A27 costs noticeably more.

Short answer

Galaxy A27 5G - Snapdragon 6 Gen 3 with 5G, 8/256 GB, 120 Hz. Galaxy A18 - the same screen type, cameras and battery for less.

Key differences

SpecSamsung Galaxy A18Samsung Galaxy A27 5G
ChipSamsung Exynos 1610Qualcomm Snapdragon 6 Gen 3
Display6.7", Super AMOLED, 1080×2340, 90 Hz6.7", Super AMOLED, 1080×2340, 120 Hz
RAM / storage4/128 GB8/256 GB
Rear cameras50 MP + 5 MP + 2 MP50 MP + 5 MP + 2 MP
Front13 MP12 MP
Battery5000 mAh5000 mAh
Charging25 W25 W
ProtectionIP64IP64
Thickness / weight7.7 mm / 196 g7.8 mm / 200 g
Pricecurrent pricescurrent prices

Specs come from the device pages on Smartphone.ua.

Chips

Samsung Exynos 1610 and Qualcomm Snapdragon 6 Gen 3.

Memory

8/256 vs 4/128 GB.

What's the same

Super AMOLED FHD+, 5000 mAh, 25 W, 50 + 5 + 2 MP cameras.

Verdict: who should buy which

  • Headroom for years - Galaxy A27 5G.
  • Saving money - Galaxy A18.

FAQ

Is the charging the same?
Yes, 25 W.

How much memory does the A18 have?
4/128 GB.

Which is cheaper?
The Galaxy A18.

Read also