Mulch Coverage Snapshot

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Area {{ formatNumber(areaSqFtValue, 1) }} sq ft Depth {{ formatNumber(depthInchesValue, 1) }} in Volume {{ formatNumber(volumeCuFtValue, 1) }} cu ft Bags {{ bagCountRoundedValue }} Weight {{ formatNumber(weightLbValue, 0) }} lb $ {{ formatNumber(bagCostValue, 2) }} Bulk $ {{ formatNumber(bulkCostValue, 2) }}
Coverage inputs
%
×
$
$
Key takeaways
  • Total coverage of {{ formatNumber(areaSqFtValue, 1) }} sq ft ({{ formatNumber(areaSqMValue, 1) }} sq m) at {{ formatNumber(depthInchesValue, 1) }} in depth.
  • Order {{ bagCountRoundedValue }} bags of {{ bagSizeLabel }} to cover the space{{ bagCountRoundedValue > 0 ? ' (exact '+formatNumber(bagCountExactValue,2)+' bags)' : '' }}.
  • Bagged mulch estimate: $ {{ formatNumber(bagCostValue, 2) }}.
  • Bulk delivery estimate: $ {{ formatNumber(bulkCostValue, 2) }}.
  • Expected material weight: {{ formatNumber(weightLbValue, 0) }} lb ({{ formatNumber(weightKgValue, 0) }} kg).
{{ allowanceNote }}
Metric Value Copy
{{ row.label }} {{ row.value }}

                    
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Introduction

Mulch coverage planning keeps soil moisture steady, shields roots from temperature swings, and suppresses weed growth by matching material volume to the bed you maintain.

The planner supports rectangular beds, circular rings, and direct area entries while letting crews switch between imperial and metric units without retyping measurements.

It converts area, depth, allowance, and density selections into volume, bag count, weight, and cost figures so buyers can compare bagged pallets against bulk deliveries with confidence.

Treat the numbers as a staging baseline and confirm slopes, edging heights, and species specific settling once the mulch is spread on site.

Technical Details

The calculator models mulch as a uniform layer across a flat footprint. All geometries convert to square feet, depth converts to feet, and the resulting rectangular prism defines base volume before allowances.

Rectangular beds multiply converted length and width. Circles convert diameter to radius for the πr² area. Custom area entries translate from square yards, square metres, hectares, or other supported units so the tool can handle plan takeoffs as well as field measurements.

A settling allowance produces a scalar that inflates volume when you expect fluff, wind loss, or traffic compaction. Bag size conversions cover cubic feet, cubic yards, litres, or cubic metres, and density conversions align kilograms per cubic metre with pounds per cubic foot to estimate handling weight.

Cost projections combine rounded bag counts with bag pricing and pair bulk volume with a per cubic yard rate. Outputs present both imperial and metric figures so procurement teams can negotiate in whichever unit schedule the supplier prefers.

Arect=LW r=D2 Acircle=πr2 S=1+s100 Dft=Din12 Dft=Dcm30.48 V=ADftS B=VBs Wt=Vρ
Symbols and units
Symbol Meaning Unit / Datatype Source
LLength of rectangular bedft / mInput
WWidth of rectangular bedft / mInput
DMulch depthin / cmInput
sSettling allowance percent0 to 100 %Input
ACoverage areasq ftDerived
SAllowance factorunitlessDerived
VTotal mulch volumecu ftDerived
VyTotal mulch volumecu ydDerived
BsBag sizecu ft / cu yd / L / cu mInput
BBag countwhole bagsDerived
ρMulch densitylb / cu ft or kg / cu mInput
WtTotal weightlb / kgDerived

Worked example

A 20 ft by 10 ft bed at a 3 in depth with a 10 percent allowance converts to an area of 200 sq ft. Depth converts to 0.25 ft and the allowance factor becomes 1.10. The resulting volume is 200 × 0.25 × 1.10 = 55 cu ft, which equals 1.11 cu yd.

With 2 cu ft bags the exact count is 55 ÷ 2 = 27.5, so the tool rounds up to 28 bags. A density of 22 lb per cu ft produces a total weight near 1,210 lb (55 × 22), or roughly 549 kg.

Interpretation shows that ordering 28 bags covers the footprint with allowance, or you can book about 2.04 cu yd of bulk mulch while planning labour for a 1,200 lb delivery.

Rounding policy

  • Inputs coerce to neutral defaults when blank. Allowance clamps to the 0 to 100 range, and area multipliers clamp to at least 1.
  • Displayed square footage uses one decimal place while metric conversions carry three decimals before export.
  • Calculations use a period as the decimal separator and Math.round applies half away from zero behaviour when resolving ties.
  • Bag counts display the rounded integer alongside the exact decimal value so crews can over-order without guessing.
  • Costs and weights report two decimal places for currency, whole pounds, and whole kilograms in line with supplier quoting practice.

Validation checks

Input validation checks
Field Rule Handling
Length Greater than zero before and after converting to feet Length must be a positive number.
Length cannot be zero after conversion.
Width Greater than zero before and after converting to feet Width must be a positive number.
Width cannot be zero after conversion.
Diameter Greater than zero before and after converting to feet Diameter must be a positive number.
Diameter cannot be zero after conversion.
Custom area Greater than zero before and after converting to square feet Coverage area must be a positive number.
Coverage area cannot be zero after conversion.
Mulch depth Greater than zero before and after converting to feet Mulch depth must be a positive number.
Mulch depth cannot be zero after conversion.
Bag size Greater than zero before and after converting to cubic feet Bag size must be greater than zero.
Bag size cannot be zero after conversion.
Settling allowance Clamped to the 0 to 100 range Values outside the range snap to the nearest bound
Area multiplier Minimum value of 1 Area multiplier must be at least 1.
Bag price / Bulk price Non-negative currency Negative values coerce to zero before calculations
Mulch density Non-negative input Negative values coerce to zero before calculations

Assumptions and limitations

  • Surfaces are treated as flat, so sloped beds and berms can need extra material in practice.
  • Mulch depth is assumed constant. Edging height changes and traffic depressions are not modelled.
  • Settling allowance is linear. The tool does not simulate staged top ups or irregular compaction curves.
  • Density remains constant even though moisture swings and species differences alter real weight.
  • Costs apply simple multiples without delivery fees, taxes, or supplier discounts.
  • The area multiplier repeats identical beds. Distinct shapes still require separate runs.

Edge cases and error sources

  • Extremely large areas can exceed common delivery sizes. The tool still computes but highlights heavy loads.
  • Very small footprints can still round to one bag because counts ceil to whole units.
  • Rapid unit toggling can introduce minor rounding drift at the thousandth place.
  • Allowance values above thirty percent merit a field check to confirm assumptions about settling or blow off.

Performance and limits

  • Calculations run in constant time because every result relies on direct arithmetic rather than iteration.
  • The browser only stores the current form state and derived metrics, keeping memory impact negligible.
  • Numeric precision follows JavaScript double precision; expect rounding noise beyond the third decimal place in repeated conversions.

Privacy and compliance

All calculations, clipboard actions, CSV, DOCX, and JSON exports run entirely in the browser, and no inputs leave the device.

Step-by-Step Guide

Plan mulch coverage for beds, rings, or custom areas.

  1. Select Measurement system and choose a footprint through Coverage shape.
  2. Enter Length and Width, Diameter, or Coverage area based on the selected geometry.
  3. Set Mulch depth and tune Settling allowance to cover expected fluff or compaction.
  4. Provide Bag size, then open Advanced for Area multiplier, Bag price, Bulk price, and Mulch density.
  5. Review the Coverage Highlights tab for narrative takeaways, then switch to Volume and Cost Breakdown to copy or export structured data.
  6. Use the JSON tab when you need to archive exact inputs and outputs for repeat orders or supplier quotes.

Once the metrics look right, share the exports with your crew or vendor and schedule delivery while soil moisture is favourable.

FAQ

Is any data stored or transmitted?

No. The tool runs locally in the browser, and clipboard, CSV, DOCX, and JSON actions generate files on your device only.

How accurate are the volume and weight results?

The model assumes a flat surface and uniform depth. Weight accuracy depends on the density you enter, so adjust it to match species, moisture, and whether you buy bulk or bagged material.

Which units can I use?

Dimensions support feet, inches, yards, metres, and centimetres. Custom areas accept square feet, square yards, acres, square metres, square centimetres, and hectares. Bag sizes allow cubic feet, cubic yards, litres, or cubic metres, and density accepts pounds per cubic foot or kilograms per cubic metre.

Can I use the calculator offline?

Yes. After the page loads it keeps working without a network connection, and previously calculated results stay visible.

How should I factor delivery or labour costs?

Use the bag and bulk price fields for material estimates, then add delivery fees or labour separately in your budgeting tool. The planner focuses on volume, count, and weight.

How much mulch do I need for 500 square metres at 5 centimetres?

Switch to metric, pick the custom area shape, enter 500 sq m with a 5 cm depth, set allowance, and the Volume and Cost Breakdown tab will show cubic metres, litres, bag counts, and weight immediately.

What does the allowance percentage represent?

Allowance inflates the calculated volume to offset settling or blow off. Zero keeps the raw volume, while higher values add a buffer so the finished depth still matches your target.

Why does the bag count round up?

Bags are sold as whole units. The tool shows the exact decimal but rounds to the next integer so you never come up short during installation.

Mulch coverage calculators support planning. Confirm final volumes with your supplier and inspect the site after spreading to refine future orders.

Glossary

Coverage area
Surface the mulch will cover after applying the area multiplier.
Settling allowance
Percentage added to raw volume so the finished depth stays on target after fluff compacts.
Allowance factor
The scalar derived from settling allowance that multiplies calculated volume.
Bag size
Volume of one retail bag, selectable in cubic feet, cubic yards, litres, or cubic metres.
Bulk price
Cost per cubic yard used for truck or trailer deliveries.
Mulch density
Mass per unit volume used to estimate total handling weight.
Rounded bag count
Exact bag count rounded up to the next whole unit to avoid shortages.