Interactive tool

Beer line length calculator

Foamy pours usually mean an unbalanced line. The standard fix is resistance balancing: line length = (keg pressure − rise × 0.5 psi/ft − 1 psi at the faucet) ÷ line resistance, with ~3 psi/ft for 3/16″ vinyl and ~0.85 psi/ft for 1/4″ vinyl — published constants, all named on this page. Your pressure, rise, and line type are inputs; nothing about your setup is guessed.

Gravity loss

0.5 psi/ft

Faucet residual

1 psi

3/16″ vinyl

~3 psi/ft

1/4″ vinyl

~0.85 psi/ft

Beer line length calculator

Keg (regulator) pressure — psi

Read it off your regulator — the right psi depends on the beer style and your keg temperature, so it is your input, not our guess.

Vertical rise, keg to faucet (ft)

Center of the keg to the faucet. Negative if the faucet sits below the keg.

Beer line

Published nominal resistances for standard vinyl draft line.

Balanced line length

3.4 ft

Pressure at faucet

1 psi

Line resistance

3 psi/ft

Length = (12 psi − 1.5 ft × 0.5 psi/ft − 1 psi at the faucet) ÷ 3 psi/ft. The result balances the system on paper; fine-tune by pouring — a slightly longer line pours slower but calmer.

The research behind this tool

Kegerator 101 →Keg sizes, explained →

Frequently asked questions

What formula does this calculator use?

The standard draft resistance-balancing formula: line length = (keg pressure − rise × 0.5 psi/ft − 1 psi) ÷ line resistance. The 0.5 psi/ft is the hydrostatic pressure lost per vertical foot the beer climbs, and the 1 psi is the residual left at the faucet for a controlled pour — both standard draft-system constants, shown in the on-page math.

What line resistances does it assume?

The published nominal figures for standard vinyl draft line: roughly 3 psi per foot for 3/16″ ID and 0.85 psi per foot for 1/4″ ID. For any other line, pick "Other" and enter the resistance from your line manufacturer’s spec sheet — the calculator will not guess it.

Why is my draft beer so foamy?

Common causes: beer that is too warm, serving pressure set too high for the line, a line too short for the pressure (which is exactly what this calculator balances), or a dirty faucet and line. Balance the line first, then chill fully before tapping, and clean the lines regularly.

Is the computed length final?

It balances the system on paper — real systems vary with temperature and hardware, so treat it as the starting point and fine-tune by pouring. Err slightly long: a longer line pours a little slower but calmer, while a too-short line pours fast and foamy.