What actually drains your phone's battery

What actually drains your phone's battery — a 2026 study puts hard numbers on the myths.

Wellington Oliveira (2026) ran 879 controlled experiments — 12,000+ data points — across WhatsApp, Instagram, TikTok and YouTube, measuring how real, user-facing settings affect energy. Several 'known' battery tips don't survive the data:

Screen brightness dominates everything else — at maximum it raised energy use by an average of 86.5%. It's by far the biggest single lever a user (or your app's defaults) controls.

Dark Theme is oversold: the measured saving was ~1.4%. On OLED it helps a little at high brightness; it is not the battery fix it's marketed as, and on LCD it barely matters.

Refresh rate is a real lever: capping at 60 Hz was the best efficiency trade-off. A 120 Hz UI feels smoother but spends energy many users would rather keep.

Video resolution is mostly a red herring: lowering it gave negligible savings, because much of video's energy cost (decoding, display, radio) is fixed regardless of resolution.

Why this matters for app teams: your defaults and any 'battery saver' messaging should follow the evidence, not folklore. Real wins come from brightness-linked behaviour (auto-dim, true-black backgrounds for OLED at high brightness) and offering a 60 Hz mode — not from headlining 'dark mode saves battery.' It also reframes performance work: shaving CPU wake-ups and background radio usually beats theme tweaks.