Primary search owner

Use this page as the broad French-drain owner. The focused gravel calculator remains a support tool for trench-fill volume minus pipe displacement.

Best matched searches: french drain calculator · french drain gravel calculator · french drain material calculator

Project add-on checks

Gravel tonnage, entered cost and slope drop

Uses the trench, pipe and allowance values from the main calculator below. Density, price and slope remain explicit user inputs.

Selected slope % Gravel density ton/yd³ Gravel price $ / yd³

Planned gravel—

Entered-density weight—

Required vertical drop—

Entered-price gravel subtotal—

Approx. fabric wrap—

Pipe run—

The slope percentage is not a design recommendation. Verify outlet elevation, drainage design, product details and local requirements separately.

Project measurements

Enter the project scope and current local cost basis.

Drain length

ft

Trench width

ft

Aggregate-filled depth

ft

Pipe outside diameter

in

Fabric overlap allowance

ft

Aggregate allowance

%

Project result

French Drain Project plan

Review the measured quantity, rounded purchase quantity and field-layout checks produced from the values you entered.

Planning estimate only. Verify product coverage, package size, supplier specifications and project requirements before purchasing.

Open Project Planner →

Project field workflow

Carry this calculation through the project

Capture trench, outlet and field-condition notes before quantity planning.

v9 workflow

1 · Measure / recordFrench Drain Field Worksheet

2 · CalculateUse this calculator with the field facts you verified.

3 · Save to projectKeep the result with the rest of the browser-local Project Workspace evidence. 4 · Execute / reconcileRecord field checks and actual usage without rewriting the original plan.

Home Measure Lab keeps measurement evidence, calculated plans and field actuals distinguishable. Project links are browser-local unless you explicitly export them.

Drain trench section

See pipe displacement, gravel and fabric wrap

A trench cross-section shows the entered pipe diameter inside the gravel envelope and the simple fabric-wrap width used by the takeoff.

Drain material check

Field plan updates with the calculator inputs.

Field check

Compare planned values with what you measure

Measured values are stored separately in this browser. They never overwrite calculator inputs or the original field plan.

Check	Planned	Measured	Delta

Field note (optional)

Enter measured values only where a comparison is useful.

A delta is descriptive only. Home Measure Lab does not apply a universal tolerance or automatic engineering/code acceptance decision.

Illustration and station tables are planning aids. Numeric calculator inputs/results remain authoritative; verify field dimensions, product instructions, project documents and applicable requirements before cutting, drilling, fastening or excavating.

Methodology

Formula & planning assumptions

Trench volume

length × width × aggregate-filled depth

Gross excavation / fill envelope.

Pipe displacement

π × (pipe diameter ÷ 2)² × length

Subtracts pipe cylinder volume from aggregate fill.

Fabric area

(trench bottom + two sides + overlap) × length

Simple wrap reference before end/details.

Field verification

compare calculated quantity with measured scope and current product/stock values

Confirms the takeoff boundary before purchase or layout marks are transferred.

How to measure this project

For French Drain Project Calculator, measure trench length, width and depth along the actual route, then enter pipe diameter and fabric/aggregate allowances that match the planned section. Record field values before applying waste or purchase rounding, use one consistent datum and unit system, and rerun unlike conditions as separate scenarios so the result can be checked against the work area.

Before you buy materials

Before ordering, verify pipe length and fittings, washed aggregate package or bulk volume, geotextile width/overlap and outlet details for the actual drainage design. Use the calculator result as a planning takeoff, then reconcile whole packages or stock pieces with current product data, project documents, on-site constraints and a deliberate allowance for cuts, laps, breakage or future repair where appropriate.

Reference

Planning boundary

Item	Solved here	Verify separately
Geometry / quantity	Arithmetic from entered measurements	Field dimensions and unlike conditions
Package / stock rounding	Whole-unit purchase count when applicable	Current product package, roll or stock size
Installation requirements	Not prescribed	Manufacturer instructions, project documents and local requirements
Project scope	One entered scenario at a time	Separate unlike zones, assemblies, product systems or field conditions before combining verified totals

Start from a drawing

Landscape & Drainage Takeoff Studio

Upload a plan or screenshot, calibrate one known dimension, trace the relevant geometry, and save the measured evidence before returning to this calculator for product-specific planning.

Open takeoff studio

Questions

Frequently asked questions

Are the default values a specification?

No. They are editable examples. Use the values from your measured project and the exact product or system you plan to install.

Does this tool replace product instructions or project requirements?

No. It is a planning and quantity tool. Installation sequence, suitability, fastening, structural requirements and code compliance must be verified separately.

Why does the purchase quantity round up?

Materials sold as whole rolls, bags, pieces or packages must be rounded to the next whole purchasable unit after allowances are applied.

Embed this calculator on another website

Use the lightweight Home Measure Lab widget. The embedded tool is noindex and does not add analytics by default; readers can open the full Home Measure Lab calculator for formulas, assumptions and source notes.

Iframe code

<iframe src="https://homemeasurelab.com/embed/calculators/french-drain-project-calculator/" title="French Drain Project Calculator" loading="lazy" style="width:100%;max-width:900px;height:760px;border:0" referrerpolicy="strict-origin-when-cross-origin"></iframe>

Keep the natural “Powered by Home Measure Lab” attribution inside the widget. Use the built-in brand attribution as provided; no extra link is required.

Next step

Keep this project moving

Follow the measurement into the most useful related reference, calculator or project view.

Related calculators

All calculators →

Plumbing & Drainage

French drain calculator: gravel, pipe, fabric and trench plan