Sonoff S31 WiFi Smart Plug vs Sonoff WiFi Smart Plug S40 comparison

Updated August 2026

Data from Amazon and official Sonoff site.

2026 verdict

In this 2026 Sonoff WiFi Smart Plug S40 vs Sonoff S31 WiFi Smart Plug comparison, Sonoff WiFi Smart Plug S40 comes out ahead thanks to rating, Overheat/Overload protection, and connectivity. What pushes it ahead is rating, Overheat/Overload protection, and connectivity, and integrations keep the advantage from looking narrow. Choose Sonoff S31 WiFi Smart Plug only if its specific feature mix matters more to you than the broader advantage from Sonoff WiFi Smart Plug S40. That makes Sonoff WiFi Smart Plug S40 the clearer recommendation in 2026.

Sonoff

Sonoff S31 WiFi Smart Plug

$10.90

Buy on Amazon USA

Winner

Sonoff

Sonoff WiFi Smart Plug S40

$10.90

Buy on Amazon USA

Feature	Sonoff S31 WiFi Smart Plug	Sonoff WiFi Smart Plug S40	Winner
Rating	4.2	4.4	Sonoff WiFi Smart Plug S40
Overheat/Overload Protection	NO	YES	Sonoff WiFi Smart Plug S40
Connectivity	2.4 GHz WiFi	2.4 GHz WiFi, Bluetooth	Sonoff WiFi Smart Plug S40
Integrations	Google Home, Alexa, Home Assistant, IFTTT	Google Home, Alexa, Samsung SmartThings, Home Assistant, IFTTT	Sonoff WiFi Smart Plug S40
Price	$10.90	$10.90	Tie
Weather Resistance	NO	NO	Tie
Plug Format	Type B	Type B	Tie
Maximum Load Power	1800W	1800W	Tie
Energy Monitoring	YES	YES	Tie
On/Off Button	YES	YES	Tie
Zibgee Router	NO	NO	Tie

Sonoff

Sonoff S31 WiFi Smart Plug

$10.90

Buy on Amazon USA

- Rating: 4.2 vs 4.4
- Overheat/Overload Protection: NO vs YES

Winner

Sonoff

Sonoff WiFi Smart Plug S40

$10.90

Buy on Amazon USA

+ Rating: 4.4
+ Overheat/Overload Protection: YES
+ Connectivity: 2.4 GHz WiFi, Bluetooth

Frequently Asked Questions

Which is better overall: Sonoff S31 WiFi Smart Plug or Sonoff WiFi Smart Plug S40?

Sonoff WiFi Smart Plug S40 has the stronger overall profile in this comparison, especially for rating, Overheat/Overload protection, and connectivity.

What is the biggest difference between Sonoff S31 WiFi Smart Plug and Sonoff WiFi Smart Plug S40?

Rating is one of the clearest differences: Sonoff S31 WiFi Smart Plug lists 4.2, while Sonoff WiFi Smart Plug S40 lists 4.4.

Which one looks better on price?

Sonoff S31 WiFi Smart Plug is listed at $10.90, while Sonoff WiFi Smart Plug S40 is listed at $10.90. Tie.

Who should buy Sonoff S31 WiFi Smart Plug?

Choose Sonoff S31 WiFi Smart Plug if your priority is its specific strengths and that matters more than rating.

Who should buy Sonoff WiFi Smart Plug S40?

Choose Sonoff WiFi Smart Plug S40 if your priority is rating and Overheat/Overload protection and that matters more than the competing advantages.

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