Technology & Computing
CMOS / RTC Coin Cell Battery Life Calculator
Estimate how many years a coin cell battery will power a real-time clock or CMOS circuit given its microamp draw.
Your inputs
Change any value to update the result instantly.
Estimated battery life
5.0861 years
Theoretical life (no self-discharge)
5.137 years
Draw
5 µA
Capacity
225 mAh
Typical CR2032 cells hold about 220-225 mAh; real-world life is shortened by self-discharge and low-voltage cutoff.
Formula and working
Life (years) = (capacity mAh × 1000) ÷ (draw µA) ÷ 8760, adjusted for self-discharge
- 1
Collect the inputs
Battery capacity (mAh) = 225; Circuit current draw (µA) = 5; Annual self-discharge rate = 1 %
- 2
Apply the formula
Life (years) = (capacity mAh × 1000) ÷ (draw µA) ÷ 8760, adjusted for self-discharge
- 3
Result
Estimated battery life = 5.0861
Frequently asked questions
Important limitation
This is an educational estimate based only on the values and formula shown. Verify current rates, rules, units, and professional standards before relying on the result. It is not personalized financial or investment advice.
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