All Irrigation Calculators

How much and how long to water established lawns, new seed and sod. 11 calculators

• Lawn Watering CalculatorWeekly water to apply after rain, in gallons or liters
• How Long to Water Lawn CalculatorMinutes per session by sprinkler type and soil
• Lawn Water Requirement CalculatorTurf water use from local ETo and grass type
• Inches of Water to Gallons CalculatorConvert water depth over an area to volume and back
• Lawn Watering Schedule CalculatorWhich days, how many cycles and when to start
• Grass Type Water Needs CalculatorCompare water needs of lawn grass species
• Grass Seed Watering CalculatorHow often and how long to water new seed
• Sod Watering CalculatorWatering plan for new sod, week by week
• Lawn Water Usage CalculatorMonthly and seasonal gallons used on your lawn
• Lawn Hose Watering Time CalculatorTime and sprinkler moves to water a lawn by hose
• Lawn Water Deficit CalculatorHow far behind your lawn is after a dry spell

Precipitation rates, run times, spacing, zones, audits and winterizing. 17 calculators

• Sprinkler Precipitation Rate CalculatorApplication rate from nozzle flow and spacing
• Sprinkler Run Time CalculatorMinutes for every zone on a multi-zone controller
• Sprinkler Zone CalculatorHeads per zone and number of zones from your supply
• Sprinkler Head Spacing CalculatorHead and row spacing from throw radius and wind
• Sprinkler Coverage CalculatorArea covered by a head, and head-to-head check
• Sprinkler Head Count CalculatorHow many heads an area needs
• Sprinkler GPM CalculatorTotal flow of all heads in a zone
• Nozzle Flow Rate CalculatorFlow from orifice size and pressure
• Matched Precipitation CalculatorPart-circle nozzle flows that water evenly
• Catch-Can Test CalculatorMeasured precipitation rate from a field test
• Distribution Uniformity CalculatorDU lower quarter, CU and run-time multiplier
• Scheduling Coefficient CalculatorRun-time multiplier for the driest spot
• Cycle and Soak CalculatorSplit run times to stop runoff
• Seasonal Adjustment CalculatorMonthly controller percentage from ETo
• Hose-End Sprinkler Output CalculatorApplication rate of a hose-end sprinkler
• Sprinkler System Design CalculatorFirst-pass plan: heads, zones and pipe sizes
• Sprinkler Blowout CFM CalculatorCompressor size and safe pressure for winterizing

Emitters, run times, zone flow, tubing layout, pressure and filtration. 17 calculators

• Drip Irrigation CalculatorPlan a drip system from your plants
• Drip Run Time CalculatorHow long to run drip for your plants
• Drip Emitter CalculatorEmitters and GPH per plant
• Drip Emitter Spacing CalculatorSpacing along inline tubing by soil
• Drip Tubing Spacing CalculatorRow spacing and tubing length for a grid
• Drip Zone Flow CalculatorTotal zone flow and maximum emitters per zone
• Drip Line Max Length CalculatorLongest run for your tubing and emitters
• Drip Precipitation Rate CalculatorApplication rate of inline drip grids
• Drip Wetted Area CalculatorWetted diameter and area per emitter
• Emission Uniformity CalculatorEU from an emitter flow test
• Drip Tape CalculatorTape per acre, flow and run time for row crops
• Micro Spray CalculatorFlow, coverage and rate of micro-sprinklers
• Bubbler Flow CalculatorTime to fill a basin and bubblers per zone
• Soaker Hose CalculatorHow long to run a soaker hose
• Tree Drip Emitter CalculatorEmitter count, placement and run time for trees
• Drip Pressure Regulator CalculatorChoose a regulator for your zone
• Drip Filter Sizing CalculatorMesh size and filter flow rating

Pipe sizing, friction loss, velocity, pressure and supply flow. 14 calculators

• Irrigation Pipe Size CalculatorPipe size from flow, with velocity and friction
• Sprinkler Pipe Size CalculatorSize each section of a sprinkler lateral
• Mainline Size CalculatorSize a mainline to a pressure-loss budget
• Poly Pipe Size CalculatorSizing for polyethylene pipe
• Multiple Outlet Friction Loss CalculatorFriction loss with the Christiansen F factor
• Lateral Line Design CalculatorPressure variation along a lateral
• Pipe Velocity CalculatorWater velocity and friction in a pipe
• Irrigation System GPM CalculatorHow much flow your supply can deliver
• Bucket Test CalculatorFlow in GPM from a bucket and a stopwatch
• Water Meter Capacity CalculatorSafe irrigation flow through a meter
• Service Line Capacity CalculatorMaximum flow through your service line
• Available Irrigation Pressure CalculatorPressure left at the sprinklers after losses
• Backflow Preventer Pressure Loss CalculatorPressure lost through a backflow device
• Valve Pressure Loss CalculatorPressure lost through a control valve

Evapotranspiration, water requirements, schedules and water budgets. 16 calculators

• Evapotranspiration CalculatorET from the weather data you have
• Reference ET CalculatorFAO-56 Penman-Monteith ETo
• Crop Evapotranspiration CalculatorETc from ETo and crop coefficient
• Hargreaves ET CalculatorETo from temperature only
• Blaney-Criddle CalculatorETo from temperature and daylight
• Pan Evaporation to ET CalculatorETo from evaporation pan readings
• Effective Rainfall CalculatorHow much rain actually reaches the roots
• Irrigation Water Requirement CalculatorNet and gross irrigation after rain and efficiency
• Irrigation Scheduling CalculatorWhen and how much to irrigate
• Irrigation Interval CalculatorDays between irrigations
• Soil Water Balance CalculatorDay-by-day root zone water ledger
• Irrigation Efficiency CalculatorApplication efficiency and net to gross
• Landscape Water Budget CalculatorMonthly budget for a property's hydrozones
• MAWA CalculatorCalifornia Maximum Applied Water Allowance
• ETWU CalculatorCalifornia Estimated Total Water Use
• Landscape Coefficient CalculatorKL from species, density and microclimate

Water holding capacity, infiltration, moisture, salinity and sodium. 10 calculators

• Available Water Capacity CalculatorWater your root zone can hold
• Soil Infiltration Rate CalculatorInfiltration rate from a ring test
• Soil Moisture CalculatorGravimetric and volumetric moisture from a sample
• Management Allowed Depletion CalculatorWater to use before irrigating
• Root Zone Depth CalculatorHow deep to water for your plants
• Wetting Front Depth CalculatorHow deep a watering will reach
• Soil Texture CalculatorUSDA texture class from sand, silt and clay
• Leaching Requirement CalculatorExtra water to control salinity
• Sodium Adsorption Ratio CalculatorSAR from sodium, calcium and magnesium
• Irrigation Water Quality CalculatorInterpret a water test for irrigation

Crop water needs, system capacity, set times, pivots and field systems. 16 calculators

• GPM per Acre CalculatorSystem capacity needed per acre
• Acre-Inches CalculatorConvert acre-inches to gallons and back
• Acre-Feet CalculatorConvert acre-feet for water rights and storage
• Irrigation Application Depth CalculatorDepth applied from flow, time and area
• Irrigation Set Time CalculatorHours per set for a target depth
• Crop Water Requirement CalculatorSeasonal crop water need from the Kc curve
• Crop Coefficient CalculatorKc for any date, adjusted for climate
• Center Pivot CalculatorDepth per revolution and required flow
• Center Pivot Acreage CalculatorIrrigated acres under a pivot
• Furrow Irrigation CalculatorDepth applied and sets for furrows
• Flood Irrigation CalculatorTime to flood a basin to a target depth
• Traveler Irrigation CalculatorTravel speed and depth for traveling guns
• Irrigation Well Capacity CalculatorCan your well supply your field?
• Orchard Irrigation CalculatorWater per tree per day
• Vineyard Irrigation CalculatorWater per vine and run time
• Greenhouse Irrigation CalculatorDaily water for benches and containers

Beds, vegetables, containers, trees, shrubs, greywater and rainwater. 9 calculators

• Garden Watering CalculatorWeekly water for garden beds
• Vegetable Garden Water CalculatorWater needs by crop and growth stage
• Raised Bed Watering CalculatorGallons per watering for a raised bed
• Container Plant Watering CalculatorWater per watering by pot size
• Tree Watering CalculatorHow much water a tree needs
• Shrub Watering CalculatorWeekly water for shrubs
• Olla Watering CalculatorHow many ollas a bed needs
• Greywater Irrigation CalculatorLandscape area your greywater can serve
• Rainwater Irrigation Supply CalculatorHarvest, tank size and demand covered

Injection rates, stock solutions and fertilizer concentrations. 6 calculators

• Fertigation CalculatorFertilizer product per application
• Injection Rate CalculatorInjector rate for a target ppm
• Injector Ratio CalculatorStock solution strength for your injector ratio
• Fertilizer PPM Calculatorppm of nutrients in a solution
• Chlorine Injection CalculatorChlorine injection rate for drip lines
• Acid Injection CalculatorAcid injection rate from a titration

Water costs, system costs and savings from upgrades. 8 calculators

• Lawn Watering Cost CalculatorWhat your lawn watering costs
• Irrigation Water Cost CalculatorWater cost per acre and per season
• Sprinkler System Cost CalculatorEstimate the cost of a new system
• Drip Irrigation Cost CalculatorMaterial cost of a drip system
• Drip Conversion Savings CalculatorSavings from converting spray to drip
• Smart Controller Savings CalculatorSavings and payback of a smart controller
• Turf Removal Savings CalculatorWater saved by replacing lawn
• Irrigation Energy Cost CalculatorPumping cost per acre-inch