Garden Hose Flow Calculator
Realistic garden-hose flow from bore, length and supply pressure (Hazen-Williams).
A 15 m × ⅝" hose on a 3 bar tap delivers ~23 L/min. Doubling hose length cuts flow ~30%; stepping up to ¾" nearly doubles it.
Formula
Note: Assumes a fully open end (no nozzle) and ignores tap/fitting losses — real flow runs slightly lower.
Garden Hose Flow Calculator is a free garden hose flow for process, mechanical and water engineers — instant, accurate and 100% client-side, with the governing formula and reference shown next to the result so the number can be defended, not just quoted.
About Garden Hose Flow Calculator
Realistic garden-hose flow from bore, length and supply pressure (Hazen-Williams). The calculation implements Hazen-Williams solved for Q with all tap pressure spent on hose friction (Hazen-Williams empirical formula (C ≈ 140 smooth hose)). A 15 m × ⅝" hose on a 3 bar tap delivers ~23 L/min. Doubling hose length cuts flow ~30%; stepping up to ¾" nearly doubles it.
How to use Garden Hose Flow Calculator
- 1Enter Hose inner diameter in mm (⅝" hose = 16 mm; ½" = 12.7; ¾" = 19).
- 2Enter Hose length in m.
- 3Enter Tap pressure in kPa.
- 4Read Flow, Time to fill 100 L instantly — no submit button needed.
- 5Need US units? Flip the SI/Imperial toggle and every field converts.
Why use Garden Hose Flow Calculator?
- ✓Implements the standard formula — Hazen-Williams solved for Q with all tap pressure spent on hose friction
- ✓Reference cited on-page: Hazen-Williams empirical formula (C ≈ 140 smooth hose)
- ✓One-click SI ⇄ Imperial toggle — values convert in place, physics stays in SI
- ✓Runs entirely in your browser — nothing uploaded, free forever
Frequently asked questions
What formula does the Garden Hose Flow Calculator use?+
It computes Hazen-Williams solved for Q with all tap pressure spent on hose friction, per Hazen-Williams empirical formula (C ≈ 140 smooth hose). The formula is displayed under the result.
What should I keep in mind when using this calculator?+
A 15 m × ⅝" hose on a 3 bar tap delivers ~23 L/min. Doubling hose length cuts flow ~30%; stepping up to ¾" nearly doubles it. Note: Assumes a fully open end (no nozzle) and ignores tap/fitting losses — real flow runs slightly lower.
Does this work for any fluid?+
Yes — density and viscosity are inputs (with common fluids suggested in the field hints), so the same physics applies to water, oils, gases and process fluids. Compute always runs in SI internally, so unit mix-ups can't corrupt the result.
Is the Garden Hose Flow Calculator free to use?+
Yes — completely free, no sign-up, no limits. It runs client-side in your browser, so inputs stay private and results are instant even on slow connections.
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