Capacitor Lifetime Calculator

It is the Arrhenius rule applied to electrochemical degradation. The rate of electrolyte evaporation, plate oxidation and self-healing increases exponentially with temperature, roughly doubling every 10 °C — the same physics as chemical reaction rates in general. Manufacturers calibrate their lifetime numbers to this rule: a 105 °C / 2000 h part delivers about 4000 h at 95 °C, 8000 h at 85 °C, and so on — until other failure modes (leakage current rise, capacitance drift) begin to dominate.

Ripple current flows through ESR and dissipates heat — P = I² × ESR. That heat raises the capacitor's internal temperature above ambient, and the 10 °C rule kicks in. Even if ambient is 25 °C, 2 A RMS through 100 mΩ ESR heats the capacitor roughly 10 °C above ambient, cutting life in half. Manufacturers derate ripple current by frequency: the rating at 10 kHz is higher than at 1 kHz because skin effect means less plate area participates at low frequencies.

Higher voltage means higher electric field across the dielectric. Field strength accelerates ionic drift, corona discharge and self-healing events in solid dielectrics, and it raises leakage current exponentially. Aluminum electrolytic life scales roughly as V⁻⁶ — drop voltage to 80% of rated and life roughly triples. Tantalum and film capacitors show weaker dependency (V⁻³), ceramic MLCCs are fatigue-limited rather than voltage-limited for DC operation.

It means the capacitor will have fewer than 5% failures after 2000 hours of continuous operation at 105 °C case temperature and rated ripple current. If you run it at 55 °C, the 2^(ΔT/10) rule gives ΔT = 50, 2^5 = 32× acceleration factor, so expected life ≈ 2000 × 32 = 64 000 h ≈ 7.3 years. Note: 105 °C refers to the capacitor's own case temperature, not ambient — you must add self-heating from ripple current.

Not really. Multi-layer ceramic capacitors age mostly from mechanical stress — temperature cycling causes the ceramic dielectric to crack, reducing capacitance over time. The rate of capacitance loss is roughly linear with number of temperature cycles, not exponential with absolute temperature. Most MLCC datasheets quote a maximum capacitance drift after 1000 temperature cycles, not a 'lifetime' number. Film capacitors age slowly too — 5% drift in 50 000 h at 85 °C is typical.

Originally a metals fatigue law that says cycles to failure ∝ (ΔT)^-n. Applied to capacitors, it becomes life ∝ I^-n where n ≈ 1.6 – 2.2 for aluminum electrolytics, relating ripple current derating to lifetime. It is empirical but well supported by accelerated testing. For our calculator we use n = 1.6 as a middle value — your datasheet may have a more specific value for their part.