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Water Tank Fill Time from Flow Rate Calculator

Time to fill or empty a tank at given flow rate.

Calculates fill time = tank volume / flow rate. Supports litre, cubic metre, and US gallon inputs. Also computes net fill rate when a drain is simultaneously open.

Daniel Oh By Daniel Oh
Published Last reviewed 1 min read

Inputs

L
L/min
L/min

Results

Enter values and click Calculate to see results.
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How to use this calculator

  1. Fill in the inputs above using the units you already have.
  2. Values update automatically as you type — no submit button needed.
  3. Hover any result row for the underlying formula and intermediate values.

Formula

t = Volume / (fill_rate − drain_rate)

In depth

Calculates fill time = tank volume / flow rate. Supports litre, cubic metre, and US gallon inputs. Also computes net fill rate when a drain is simultaneously open.