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Sleep Mode Battery Life Calculator

Work out sleep mode battery life instantly with clear inputs, formula shown and shareable results.

About Sleep Mode Battery Life Calculator

Average current is the duty-weighted sum of active and sleep current, and battery life is capacity divided by that average. At a 0.5% duty cycle the 22 mA active current still contributes 110 microamps — far more than the 4.5 microamp sleep current, so reducing active time matters most.

Formula

Duty-cycled current

I_avg = I_active x duty + I_sleep x (1 - duty); life = capacity / I_avg

Worked example

With the default values below, Sleep Mode Battery Life Calculator returns Battery life of 2.39. Change any input above and every figure here is recalculated in your browser.

Inputs used

Battery capacity
2,400 mAh
Active current
22 mA
Sleep current
4.5 µA
Active duty cycle
0.5 %

Results

Battery life
2.39 years
Average current
114.48 µA
Active share of consumption
96.09% %
Battery life
874 days

Step by step

  1. 1Values used
  2. 2Duty-cycled current
  3. 3Battery life= 2.39 years
  4. 4Average current= 114.48 µA
  5. 5Active share of consumption= 96.09 %
  6. 6Battery life= 874 days

Assumptions and limits

  • The result is derived only from the 4 inputs listed above. Anything not among them is not part of the calculation.
  • In particular, this calculator does not take inflation, tax, fees or charges or compounding frequency into account.
  • Figures are rounded for display to 2 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.

How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.

Frequently Asked Questions

Should I optimise sleep current or active time?

Compute the split first. Once active consumption dominates, shortening the wake period or raising the clock to finish faster beats shaving microamps from sleep.

Does self-discharge matter?

Yes, at these currents it often dominates. A lithium primary cell losing 1% a year sets a ceiling of roughly ten years no matter how low the load is.

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