Tools & Calculators
Fourteen free tools, in the order a wet yard actually gets solved: work out what's wrong, size the fix, then price it and get quotes you can compare. They chain together — a soil test feeds the dry well and rain garden tools, the roof runoff figure feeds the downspout and dry well tools, and every result can be copied as a link.
None of them diagnose a yard or design a system — that needs measured fall, a confirmed outlet, and someone standing on the property. Every constant they use, and where it comes from, is on the how we calculate page.
Work out what's wrong
Start here. These narrow the problem before you size or price anything.
Yard Drainage Solution Finder
LiveEight questions about your yard's conditions. Returns the approaches that fit, what to check next, what to ask a contractor — and a link into the right calculator for each.
Open the tool →Soil Drainage Rate Calculator
LiveTurn a backyard perc test into inches per hour and minutes per inch, see which fixes your soil rules in or out, and send the rate into the dry well and rain garden tools.
Open the tool →Yard Slope Calculator
LiveTurn a string-line measurement into a grade, find out whether you have enough fall to drain, and see the drop you need for a pipe or swale.
Open the tool →Roof Runoff Calculator
LiveHow much water your roof sheds in a storm and how much lands at each downspout, with NOAA storm depths for your city.
Open the tool →Size it
Each takes the water and the soil, sizes the fix, and says plainly when it is the wrong fix.
Downspout Calculator
LiveHow many downspouts your roof needs and what size — from roof area, pitch, rainfall intensity and gutter length — plus how much water lands at each outlet.
Open the tool →Yard French Drain Sizing Calculator
LiveDesign flow from the roof, paving and lawn the drain intercepts, checked against the real capacity of 4-inch and 6-inch pipe at your slope.
Open the tool →French Drain Gravel Calculator
LiveA yard French drain as a shopping list: stone in yards and tons, pipe, fabric, spoil to haul, turf to cap it, a materials cost range — and whether the run can reach an outlet.
Open the tool →Dry Well Sizing Calculator
LiveSize a dry well from the water it must hold — pit dimensions, tons of #57 stone, the smaller open-chamber option, and an honest check on whether your soil will drain it.
Open the tool →Rain Garden Size Calculator
LiveSize a rain garden from the roof, paving and lawn feeding it: area, footprint, dig depth, soil mix and mulch — and whether the soil empties it in 24 to 48 hours.
Open the tool →Catch Basin Calculator
LiveBasin, grate and outlet pipe size from the lawn, paving and roof draining to a low spot, how many basins you need, a shopping list and DIY vs installed ranges.
Open the tool →Retaining Wall Calculator
LiveBlocks, caps, base and drainage stone in tons, fabric, pipe and geogrid — with DIY and installed planning costs and the drainage line item priced.
Open the tool →Price it and hire well
Planning ranges, never quotes — and the tools that make quotes comparable.
Yard Drainage Cost Calculator
LiveBuild your drainage plan line by line — French drain, basins, buried downspouts, dry well, regrading — and get a planning range for the whole job, DIY or installed.
Open the tool →Drainage Quote Analyzer
LivePaste or upload a drainage quote and see how clearly it's documented — what it specifies, what it leaves vague, and the questions to ask before you sign.
Open the tool →Contractor Outreach Kit
LiveWrite one clear message to send several drainage contractors so their quotes come back comparable, plus a checklist to vet each one. You send it yourself.
Open the tool →What goes in, what comes out
| Tool | You enter | You get |
|---|---|---|
| Yard Drainage Solution Finder | What you see, when it drains, your soil, whether there's an outlet | Fixes worth investigating, fixes ruled out and why, checks to make |
| Soil Drainage Rate Calculator | How far the water dropped, and in how long | Rate, soil band, what it rules in or out |
| Yard Slope Calculator | Drop and distance, or a run and a target grade | Percent, inches per foot, a drainage verdict |
| Roof Runoff Calculator | Roof footprint, rainfall or your city, downspouts | Gallons per storm, gallons per downspout |
| Downspout Calculator | Roof area, pitch, region, gutter length | Downspout count and size, gallons per outlet |
| Yard French Drain Sizing Calculator | Catchment areas, soil, storm, slope, pipe material | Pipe size, capacity used, when slope is the real problem |
| French Drain Gravel Calculator | Trench length, width, depth, pipe, drop to the outlet | Materials list with quantities and a planning cost |
| Dry Well Sizing Calculator | Roof or paved area, storm, soil or perc rate, depth | Gallons, pit and chamber size, stone, drain-down verdict |
| Rain Garden Size Calculator | Catchment areas, storm, ponding depth, soil | Area, footprint, dig list, overflow, drain-down verdict |
| Catch Basin Calculator | Areas draining in, storm, low spots, outlet slope | Grate and basin size, pipe size, materials, planning ranges |
| Retaining Wall Calculator | Wall length and height, block type, outlet run | Full materials list, height verdict, two cost ranges |
| Yard Drainage Cost Calculator | The fixes you need, quantities, site factors | Low–high range per line and in total, cheapest-first order |
| Drainage Quote Analyzer | A quote, pasted or uploaded | Scope items named, scope items missing, questions to ask |
| Contractor Outreach Kit | Your problem, what you've checked, what you want priced | A message to send, a vetting checklist, a tracker |
Not sure where to begin? Start here walks through the four observations that narrow most drainage problems down before you even open a tool.