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Refrigerator Generator Size Calculator

What generator keeps your fridge alive in an outage?

Size a backup generator to keep your fridge, freezer, and essentials running. Accounts for compressor surge wattage (typically 3× running watts) plus a 20% safety margin per portable-generator manufacturer guidance.

⏱ ~30 secCompressor surge × 1.2 marginInstallation & Setup
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Surge
Single-speed compressor
20%
Margin
Safety buffer
2,000W
Practical min
Fridge only
5,000W
Fridge + freezer
+ essentials
STEP 01

Five inputs.
Real generator size.

Sum running watts. Multiply each compressor by 3× for surge. Add 20% safety margin.

W
From the inside-cabinet nameplate.
W
Updates live as you type
Recommended generator
5,000W
3,500–5,000W portable
Running watts
1,300
Starting watts
3,700
Under the hood

Surge watts. Safety margin.

Compressor surge multipliers come from manufacturer spec sheets (3× for single-speed). The 20% margin matches portable-generator manufacturer guidance to prevent overload trips.

  1. 01

    Sum running watts

    Add fridge + freezer + each enabled essential. This is the steady-state load.

  2. 02

    Sum starting watts

    Compressor loads × 3 (single-speed surge). LED lights have no surge. Well pump and AC use 3× surge.

  3. 03

    Add 20% safety margin

    Required generator size = starting watts × 1.2. Round up to next standard portable or standby tier.

  4. 04

    Pick a generator class

    <3,000W: portable inverter. 3,500–5,000: standard portable. 5,000–7,500: tri-fuel portable. 7,500+: standby recommended.

Questions

Frequently asked

A typical full-size fridge runs at 100–800 watts but surges to 1,200–2,400 watts at startup. A 2,000–3,000W portable generator is the practical minimum for fridge-only backup.
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Browse top-freezer refrigerators at Fridge.com — the lowest-wattage configuration on the market and easiest to keep alive on a small generator.

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