Hose Pressure Loss Calculator

Dial in hose size for even watering today. Add fittings, slopes, and supply pressure easily. See loss instantly, then export results for records later.

Calculator

Choose the model that fits your detail level.
Profile sets roughness and flow coefficient values.
Used to estimate remaining pressure at the outlet.
Enter the full run, including sections and reels.
Common sizes: 1/2", 5/8", 3/4".
Use your sprinkler/nozzle rating or a bucket test.
Mostly impacts Darcy calculations via viscosity.
Downhill? Enter 0 for a conservative estimate.
Adds minor losses from common connectors and valves.
Fittings and attachments
Counts are optional; set to zero if not used.
Typical K values are pre-set.

Formula used

This calculator estimates head loss (feet of water) and converts it to pressure loss.

  • Hazen–Williams (US form): hf = 4.52 · L · Q1.85 / (C1.85 · d4.87)
  • Darcy–Weisbach: hf = f · (L/D) · (v² / (2g)) with f from Swamee–Jain.
  • Minor losses: hm = K · (v² / (2g)) summed across fittings.
  • Elevation: uphill gain adds static head equal to the elevation change.
  • Pressure conversion: ΔP(psi) ≈ h(ft) / 2.31.

How to use this calculator

  1. Measure hose length from tap to the watering point.
  2. Enter inside diameter and a realistic flow rate.
  3. Pick a hose profile that matches your line condition.
  4. Add fittings and attachments you actually use.
  5. Press calculate, then review loss and remaining pressure.

Example data table

Sample scenarios to illustrate how diameter and length affect watering performance.

Scenario Length Diameter Flow Supply Typical outcome
Patio pot watering 50 ft 5/8 in 3 gpm 45 psi Low loss, steady hand spray
Lawn sprinkler run 100 ft 1/2 in 5 gpm 50 psi Noticeable loss, sprinkler may weaken
Long bed irrigation 200 ft 3/4 in 6 gpm 55 psi Lower loss, better end pressure
Attachments heavy 100 ft 5/8 in 5 gpm 50 psi Fittings add loss, reduce nozzle punch
Tip: If pressure is low, increase hose diameter, reduce flow, shorten runs, or split zones.

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Important Note: All the Calculators listed in this site are for educational purpose only and we do not guarentee the accuracy of results. Please do consult with other sources as well.