Calculate tank filling or detention time, required volume, or flow rate using t = V/Q, including constant simultaneous inflow and outflow.
Direct solving is free and needs no account. Have a word problem instead? Submit it as text.
Worked examples
These are the solver's own reference problems — the answers come from published sources or independent hand computation, never from the solver itself. The solution below is the live solver output for each.
Example 1
fill time: 500 m³ at 0.05 m³/s
Given
solve for
time
volume
500 m^3
flowrate
0.05 m^3/s
Assumptions
Constant flowrate(s) and a simple volume balance; the tank neither leaks nor overflows during the process.
Solution steps
Apply the volume balance
Volume equals flowrate times time; rearrange for the unknown.
V = Q · t
2.778 h
= 2.778 h
Results
Fill / detention time t
2.778h
Where this answer was checked
source
t = V/Q — simple fill
verified by
hand-recomputed
derivation
t = 500/0.05 = 10 000 s = 2.778 h.
Example 2
US operator math: 100,000 gal at 350 gpm
Given
solve for
time
volume
100000 gal
flowrate
350 gpm
Assumptions
Constant flowrate(s) and a simple volume balance; the tank neither leaks nor overflows during the process.
Solution steps
Apply the volume balance
Volume equals flowrate times time; rearrange for the unknown.
V = Q · t
4.762 h
= 4.762 h
Results
Fill / detention time t
4.762h
Where this answer was checked
source
t = V/Q in gallons and gpm — detention time
verified by
hand-recomputed
derivation
t = 100000/350 = 285.71 min = 4.762 h.
Example 3
size a basin for 4 h detention at 2 MGD
Given
solve for
volume
flowrate
2 mgd
time
4 h
Assumptions
Constant flowrate(s) and a simple volume balance; the tank neither leaks nor overflows during the process.
Solution steps
Apply the volume balance
Volume equals flowrate times time; rearrange for the unknown.