Electrolytic Capacitor Life Calculator (10 °C Rule)
By Santaji GadepatilinUpdated October 27, 2026
Aluminium electrolytic capacitors wear out as their electrolyte slowly dries, and heat speeds this up dramatically. They are often the first part to fail in power supplies and drives — see this electrolytic capacitor lifetime calculation and how the failure modes of electrolytic, ceramic and tantalum capacitors differ.
How to use the electrolytic capacitor life calculator
Enter the capacitor’s rated life and rated temperature from the datasheet (for example 2,000 h at 105 °C), and the actual core temperature in your circuit. You get the expected life in hours and years of continuous operation.
For more background, read Capacitor ESR Explained.
Electrolytic capacitor life formula
L = L₀ × 2(T₀ − T) ÷ 10
Life at different temperatures
| Core temperature | 1,000 h @ 85 °C | 2,000 h @ 105 °C | 5,000 h @ 105 °C | 10,000 h @ 105 °C |
|---|---|---|---|---|
| 85 °C | 1,000 h | 8,000 h | 20,000 h | 40,000 h |
| 75 °C | 2,000 h | 16,000 h | 40,000 h | 80,000 h |
| 65 °C | 4,000 h | 32,000 h | 80,000 h | 160,000 h |
| 55 °C | 8,000 h | 64,000 h | 160,000 h | 320,000 h |
| 45 °C | 16,000 h | 128,000 h | 320,000 h | 640,000 h |
| 40 °C | 22,627 h | 181,019 h | 452,548 h | 905,097 h |
One year of continuous use is 8,760 hours. Manufacturers often cap estimates at 15 years because of seal ageing.
Extending capacitor life
- Keep capacitors away from heat sinks, resistors and transformers.
- Choose 105 °C, long-life series for power supplies and drives.
- Stay within the ripple current rating — ripple heats the core.
- Improve enclosure ventilation; every 10 °C counts double.
Why it matters
Electrolytic capacitors are the most common wear-out part in power supplies, VFDs and UPSs. Rising ESR and falling capacitance are early warning signs, which is why drive makers recommend replacing DC-bus capacitors on a schedule.
Frequently asked questions
What is the 10-degree rule for capacitors?
The life of an aluminium electrolytic capacitor roughly doubles for every 10 °C drop in its core temperature, because electrolyte evaporation follows the Arrhenius law.
How long will a 2,000-hour, 105 °C capacitor last at 55 °C?
2,000 × 2⁵ = 64,000 hours, or about 7.3 years of continuous use.
Should I use ambient or core temperature?
Core (hotspot) temperature — ambient plus self-heating from ripple current. Many manufacturers also include a ripple current factor.
Does voltage affect life?
Less than temperature for most aluminium electrolytics. Some manufacturers add a factor for operating below rated voltage.