RainYard Tools

RainYard Tools

French drain, runoff, and yard drainage calculators

Practical homeowner tools for French drains, downspouts, runoff, dry wells, swales, gravel, trench storage, and safe overflow paths.

Browse calculatorsOpen French drain planner
1 inch on 1,000 sq ft623 gal
French drain keyword260 US
Typical stone voids35-45%
Tool pages34

Start here

Pick the job, then run the numbers.

French Drain Calculator

Estimate runoff, trench storage, gravel, and pipe length for a French drain run.

Yard Drainage Calculator

Estimate runoff, temporary storage, and surface area needed when a yard stays wet after rain.

Roof Runoff Calculator

Convert roof area and rainfall into gallons and cubic feet of runoff.

French Drain Gravel Calculator

Estimate gravel, fabric, and pipe length for a French drain trench.

French Drain Cost Calculator

Estimate gravel, fabric, pipe, and labor cost for a French drain installation.

Downspout Drainage Calculator

Estimate peak downspout flow, short-burst volume, and target fall for an extension or drain line.

Plan in order

Source, path, storage, overflow.

Most yard water fixes fail when one of those four parts is skipped. The pages here keep each decision small enough to check before you buy pipe, gravel, or drain boxes.

  1. SourceMeasure roof, pavement, and uphill flow.
  2. PathCheck slope and avoid sending water toward structures.
  3. StorageSize barrels, trenches, basins, stone, or soil volume.
  4. OverflowGive every full system somewhere safe to drain.

French drain cluster

Plan the trench before you trench the yard.

French Drain CalculatorCompare storm runoff with trench storage, gravel, and pipe length.French Drain Gravel CalculatorEstimate gravel, fabric wrap, and linear pipe for the trench you already picked.French Drain Cost CalculatorScreen gravel, fabric, pipe, and labor before requesting bids.Drainage Slope CalculatorCheck whether the line can actually discharge once it reaches daylight or a pop-up emitter.

By problem

Start with what you see.

Downspouts dump beside the houseCheck peak roof flow, extension grade, and next-step drainage options.Water runs along a fence or foundation edgeCompare French drain storage with the storm volume before digging.The yard stays soft after rainEstimate runoff, temporary storage, and how much basin area the yard really needs.A low spot needs hidden storageCompare dry well, stone trench, swale, and overflow options.

All pages

Calculators and field notes.

Catch Rain

Roof runoff, barrels, cisterns, and first-flush sizing.

Rain Barrel Fill CalculatorRoof Runoff CalculatorGutter Flow CalculatorDownspout Count CalculatorCistern Size CalculatorIrrigation Days CalculatorFirst Flush Diverter Calculator

Move Water

French drains, slope, swales, downspouts, trenches, and surface flow.

Driveway Runoff CalculatorYard Drainage CalculatorFrench Drain CalculatorFrench Drain Gravel CalculatorFrench Drain Cost CalculatorDrainage Slope CalculatorDownspout Drainage CalculatorSwale Capacity CalculatorDry Creek Stone Calculator

Soak It In

Rain gardens, dry wells, trenches, soil, stone, and pavers.

Rain Garden Size CalculatorDry Well Size CalculatorPermeable Paver Base CalculatorSoil Infiltration Rate CalculatorRain Garden Soil Mix CalculatorStone Trench Storage Calculator

Plan the Site

Material checks, cost ranges, conversions, and field notes.

Berm Volume CalculatorSoil Amendment Volume CalculatorNative Plant Spacing CalculatorRain Garden Mulch CalculatorStormwater Fee Estimate CalculatorImpervious Area Percent CalculatorRainfall Depth ConverterGallons to Cubic Feet ConverterStone Yards to Tons ConverterDesign Storm Cheat SheetYard Drainage ChecklistStormwater Credit Planner