Water & Irrigation Calculators

Which water calculator do you need?

• Rain Barrel & Rainwater Harvesting Calculator: Rainwater collected from your roof per storm and per year, and how many barrels to fill.
• Watering Schedule Calculator: How much to water each week after rain, split into sessions that suit your soil.
• Irrigation Scheduling Calculator: How many days between irrigations and how much to apply, from soil, roots and ET.
• Irrigation Run Time Calculator: How many minutes to run each zone to apply the depth of water you want.
• Sprinkler Calculator: How many sprinkler heads a rectangular lawn needs, which types, and how many zones.
• Sprinkler Coverage Calculator: Area one head covers and the precipitation rate of your layout, with time to apply water.
• Drip Irrigation Planner: Emitters, drip line and fittings for your rows, with total flow and zones.
• Drip Emitter Calculator: How long to run drip emitters to give each plant the water it needs.
• Drip Flow Rate Calculator: Total flow of your drip system and whether your tubing can carry it.
• Drip Irrigation Pump Calculator: The flow, total head and power a pump needs to run your drip system from a tank or well.
• Rainwater Calculator: How much rainwater your roof collects a year and per storm, and how long it lasts.
• Crop Water Requirement Calculator: Daily and weekly water use of a crop from reference ET and its crop coefficient.
• Evapotranspiration Calculator: Estimate daily reference evapotranspiration from temperature, latitude and date.

Every tool works in metric or imperial units, shows its formula and a worked example, and lets you edit the assumptions that vary from garden to garden. Results stay on your device; nothing you enter is stored.