Battery Series and Parallel Calculator

Calculate ideal pack voltage, amp-hour capacity, watt-hours, and cell count from a series-parallel arrangement.

Unit voltageNumber from 0.001 to 1000000 V.Unit capacityNumber from 0.001 to 1000000 Ah.Units in seriesWhole number from 1 to 100000.Parallel stringsWhole number from 1 to 100000.

Use the units shown beside each field. Decimal and scientific notation are accepted for non-integer fields; blanks, commas, fractions and non-finite entries are rejected.

Calculate

Pack voltage14.8 V

Pack capacity6 Ah

Nominal pack energy88.8 Wh

Total units8

The displayed results apply to the default example. Enable JavaScript to calculate other inputs.

How to use this calculator

1. Replace the example values with measurements or ratings for the exact vehicle, circuit, component or system.
2. Keep every value in the labeled unit and use manufacturer data where available.
3. Select Calculate, then review the result together with the limitations and safety notes.

Formula and method

Series units add voltage while amp-hours stay constant. Parallel strings add amp-hours while voltage stays constant. Wh = pack volts × pack Ah.

Calculations run in your browser. Results are hidden whenever an input changes or validation fails, preventing an older result from being mistaken for a new calculation.

Worked example

Unit voltage = 3.7 V; Unit capacity = 3 Ah; Units in series = 4; Parallel strings = 2. The calculator returns Pack voltage = 14.8 V; Pack capacity = 6 Ah; Nominal pack energy = 88.8 Wh; Total units = 8.

The worked example uses the same defaults shown in the interface, allowing the formula and displayed result to be checked together.

Limitations and safety

Cells or batteries must be compatible, balanced, protected and connected with correctly rated components. This ideal calculator does not design a safe battery pack.

This is an educational planning model. Confirm ratings, tolerances, code requirements and safe procedures with manufacturers and qualified professionals before purchasing, modifying, wiring or operating equipment.

Frequently asked questions

Does connecting batteries in parallel increase voltage?

No. Ideal parallel strings keep the unit voltage and add amp-hour capacity.

Why does the calculator reject my entry?

Each field shows its supported range. Whole-number fields reject decimals, and all fields reject blanks, words, comma-formatted numbers, fractions and non-finite values.

How should I use the displayed precision?

Keep extra digits while checking the calculation, then round to the precision supported by the measurements, component tolerances and published ratings.

Review notes and reference

Reviewed October 4, 2026. The formula and default example were checked together. The script was tested for defaults, input boundaries, invalid formats, condition-specific errors and recovery after an error. Reference: OSHA electrical safe-work requirements. Explanations and examples are original.

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