IrrigationForge

Free Irrigation Calculators & System Planning Tools

Calculate irrigation flow, sprinkler zones, run time, water use, drip irrigation and sprinkler head requirements - with the formula, a worked example and the professional sources shown on every page.

Plan my system in 8 steps Browse all calculators

The planning chain

Measure supply → size zones → pick hardware → build the schedule → budget the water. Start with the Irrigation Planner for the guided path, or use any calculator on its own - every tool links to the next step. Not sure if a design will work? Run the System Check for a five-point feasibility review.

Popular Calculators

Sprinkler Zone CalculatorFree sprinkler zone calculator. Irrigation Run Time CalculatorFree irrigation run time calculator. Irrigation Water Budget CalculatorFree irrigation water budget calculator. GPM CalculatorMeasure available water flow in GPM with the bucket test. Drip Irrigation CalculatorFree drip irrigation calculator. Sprinkler Head CalculatorFree sprinkler head calculator.

From calculation to planning

A sprinkler system is a chain of decisions: how much water you have, how many heads a zone can carry, how long to run it and what it costs in gallons. Each calculator on IrrigationForge handles one link in that chain and links to the next one, so you can plan a complete system step by step.

Every page shows the formula it uses, a worked example, its assumptions and the professional sources behind it - because a number without context is just a guess. All results are planning estimates to guide your design, not replacements for on-site verification.

Guides & Answers

How Many Sprinkler Heads Per Zone?How many sprinkler heads fit on one zone? The answer depends on measured GPM, head flow and a safety margin - here is the math, with typical numbers. How Long Should Sprinklers Run?How long to run sprinklers depends on application rate and weekly target. How Much GPM Does a Sprinkler System Need?A sprinkler system's GPM depends on head count and nozzle type: sprays 1. How Many Zones Do I Need?How many sprinkler zones does your yard need? It comes from area, head spacing and measured water flow - here is the calculation with typical numbers. How to Measure Your Water Flow (The Bucket Test)Step-by-step guide to measuring your available water flow with a bucket.