A Galaxy Note20 Ultra that overheats is working hard or aging. Heat is normal when gaming, charging fast, recording video or using 5G in a weak signal area. Take off the case, move the phone into shade, close the heavy app and let it cool. Check Settings, Battery and device care, Battery, for the apps using most power, restart, and update One UI and your apps. The 120 Hz screen and a worn battery on a phone of this age add heat. If it is hot at idle, restart in Safe mode, and if it stays hot, contact Samsung.
Differential
Likely causes of “Samsung Galaxy Note20 family gets hot or shows a temperature warning”, and how to tell them apart
- 1
Gaming or recording
What separates it Heat during long sessions
How to confirm Rest the phone and remove the case
- 2
5G and weak signal
What separates it Hot on mobile data with few bars
How to confirm Use Wi-Fi or LTE
- 3
120 Hz and fast charging
What separates it Heat while charging at full brightness
How to confirm Use 60 Hz and avoid use while charging
- 4
A runaway app
What separates it Hot at idle
How to confirm Test in Safe mode
- 5
An aged battery
What separates it Hot on charge and short runtime
How to confirm Ask Samsung about a battery replacement
Before you touch a setting
Record this first — changing settings destroys the evidence
- What the phone was doing
- The top apps by battery
- Whether Safe mode stays cool
Try in this order
0 of 5 completedStop and cool
ReversibleClose apps and remove the case.
Check battery usage
ReversibleFind the apps using most power.
Change display settings
ReversibleUse the standard refresh rate.
Test in Safe mode
ReversibleFind out whether an app is the cause.
Update
ReversibleInstall One UI and app updates.
Model-specific
What is true of this model and not of its siblings
- Display
- The Note20 Ultra has a 6.9-inch 120 Hz display.
- Age
- A 2020 battery has had many cycles; battery health matters.
Stop boundary
When this stops being a self-service repair
- !If hot at idle in Safe mode, contact Samsung
Evidence ledger
Sources behind this answer
Exact questions
Common questions
Does the S Pen affect heat?+
No, the S Pen has its own small battery and does not heat the phone.
Why does the Note20 Ultra get hot when charging?+
Fast charging and a bright screen generate heat. Charge with the screen off if it gets hot.
Is a hot Note20 Ultra dangerous?+
A warm phone is normal, but a swollen or smelly one needs immediate attention.
Does Samsung still update the Note20 Ultra?+
Check Settings, Software update, since older phones eventually stop receiving updates.