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GravelCalc — Help & Support

Contents

Getting Started

GravelCalc is a fast, reliable volume and weight calculator for landscaping and fill materials. It supports gravel, mulch, topsoil, sand, decomposed granite, and river rock. It works completely offline — no account needed, no internet required.

The app has three tabs:

  • Calculator — Pick a material and shape, enter dimensions, and get instant volume in cubic yards or metres, weight in tons or tonnes, and truck loads.
  • Project — Save multiple calculations, see combined totals, and estimate costs.
  • Reference — Quick-reference tables for material densities, recommended depths, coverage per cubic yard, waste factors, and truck sizes.

Using the Calculator

  1. Choose a material from the horizontal row at the top: Gravel, Mulch, Topsoil, Sand, DG (Decomposed Granite), or River Rock. Each material has its own density, so weight calculations are accurate for your chosen fill.
  2. Choose a shape from the second row: Rectangle, Circle, Triangle, or L-Shape.
  3. Enter your dimensions. In imperial mode you enter feet, inches, and fractions. In metric mode you enter metres and centimetres.
  4. Pick a depth from the quick-select buttons, or tap the slider icon to enter a custom depth.
  5. Set a waste factor using the buttons below. The default is 7% — a good general-purpose value.
  6. View your results at the bottom of the screen: total volume, weight based on material density, and truck loads required.
  7. Add to Project — tap the button below the results to save this calculation to your project for combined totals.
Tip: Tap Done on the keyboard or swipe down on the screen to dismiss the keyboard and see your results.

Supported Materials

GravelCalc includes six common landscaping and fill materials, each with accurate density data for weight calculations:

Material tons/yd³ tonnes/m³ Typical Use
Gravel 1.40 1.83 Driveways, drainage, base layers, paths
Mulch 0.40 0.52 Garden beds, tree rings, playground areas
Topsoil 1.08 1.41 Garden beds, lawn prep, raised beds
Sand 1.35 1.76 Paver base, sandboxes, levelling
Decomposed Granite 1.50 1.96 Pathways, patios, xeriscaping
River Rock 1.35 1.76 Decorative landscaping, dry creek beds, borders
Why density matters: Landscaping materials are often sold by weight (tons or tonnes) rather than volume. GravelCalc converts your volume calculation to weight automatically using the density of your selected material, so you can order the right amount whether your supplier prices by the yard or by the ton.

Supported Shapes

GravelCalc handles the four most common area shapes for landscaping:

  • Rectangle — The most common shape. Driveways, garden beds, paths, and patios. Enter length and width.
  • Circle — Round areas like tree rings, fire pit surrounds, and circular patios. Enter diameter.
  • Triangle — Triangular garden beds and corner areas. Enter base and height.
  • L-Shape — An L-shaped area calculated as a rectangle minus a cutout. Enter overall length and width, then the cutout length and width. Great for L-shaped paths, driveways that wrap around a corner, or garden beds with notches.

All shapes use a shared depth picker since landscaping materials are spread at a consistent depth across the area.

Waste Factor

The waste factor adds extra volume to your order to account for uneven ground, compaction, spillage, and spreading irregularities. It is always better to have a little extra than to come up short.

  • 0% — Exact volume only (not recommended for ordering).
  • 5% — Simple rectangular areas on flat, prepared ground.
  • 7% — Standard recommendation for most landscaping jobs.
  • 10% — Irregular shapes, sloped ground, or areas with obstacles.
  • 15% — Complex layouts, hard-to-access areas, or when compaction is expected.
  • Custom — Tap the slider icon to enter any percentage you need.
Pro tip: Materials like gravel and decomposed granite compact significantly after spreading. If you plan to compact the material with a plate compactor or tamper, add an extra 10–15% on top of your usual waste factor.

Settings & Customisation

Tap the gear icon in the top-right corner of the Calculator tab to open Settings.

Unit System

Switch between Imperial (feet, inches, cubic yards, tons) and Metric (metres, centimetres, cubic metres, tonnes). The app defaults to whatever measurement system is standard in your country.

Truck Capacity

Set the capacity of a standard dump truck in your area. This is used to calculate how many truck loads you need. Common values:

  • 10 yd³ — Standard dump truck in the US and Canada.
  • 7.6 m³ — Standard dump truck in Australia, UK, and most metric countries.

Pricing

Set a price per cubic yard (or per cubic metre) and an optional delivery fee to see cost estimates in the Calculator and Project tabs.

Reset to Defaults

Scroll to the bottom of Settings and tap Reset All Settings to restore all settings to their original values for your region.

Setting Up Cost Estimates

GravelCalc can estimate the cost of your material order. Here is how to set it up:

  1. Tap the gear icon on the Calculator tab to open Settings.
  2. Under Pricing, enter the price per cubic yard (or per cubic metre in metric mode). This is the rate your local supplier charges. Call them for a quote — prices vary by material, region, and time of year.
  3. Optionally enter a delivery fee. Many suppliers charge a flat fee per truck load.
  4. Your cost estimates appear in the See Cost button on the Calculator, and in the Project Total card.
Note: Cost estimates are for planning purposes only. Actual prices depend on your supplier, material grade, delivery distance, and other factors. Always confirm pricing with your supplier before ordering.

Project Tab & Totals

The Project tab lets you combine multiple calculations into a single job estimate:

  • Add calculations from the Calculator tab by tapping Add to Project below the results.
  • See combined totals — total volume, total weight, total truck loads, and estimated cost for the entire project.
  • Mix materials — add gravel for the driveway, mulch for the garden beds, and topsoil for the lawn — all in one project.
  • Remove individual items by long-pressing on a row and selecting Delete.
  • Share a summary — tap Share Project Summary to generate a plain-text summary you can send to a supplier or client via text, email, or any app.
  • Clear the project by tapping the trash icon in the top-right corner.

Your project is saved automatically and persists between app launches.

Reference Guide

The Reference tab gives you quick-access tables for common landscaping data:

  • Material Densities — Weight per cubic yard and per cubic metre for all six materials.
  • Recommended Depths — How deep to spread each material for best results.
  • Coverage per Cubic Yard — How many square feet one cubic yard covers at different depths.
  • Waste Factor Guide — Recommended waste percentages for different job types.
  • Common Truck Sizes — Capacities for pickup trucks through to tandem dump trucks.

All reference data displays both imperial and metric values.

Formulas & How Calculations Work

GravelCalc uses standard geometry formulas for area and volume, combined with material density data for weight. Here is exactly how every calculation works.

Rectangle

A simple rectangular area at a uniform depth.

Volume = Length × Width × Depth

Imperial inputs are converted so all measurements are in feet before multiplying. Depth in inches is divided by 12 to convert to feet. The result in cubic feet is divided by 27 to get cubic yards.

Example: A 20 ft × 12 ft driveway at 4" deep
Volume = 20 × 12 × (4 ÷ 12) = 80 ft³ = 2.96 yd³

Circle

A circular area at a uniform depth.

Volume = π × (Diameter ÷ 2)² × Depth
Example: A 10 ft diameter tree ring at 3" deep
Volume = π × 5² × (3 ÷ 12) = 19.63 ft³ = 0.73 yd³

Triangle

A triangular area at a uniform depth.

Volume = 0.5 × Base × Height × Depth
Example: A corner bed with 8 ft base, 6 ft height, at 3" deep
Volume = 0.5 × 8 × 6 × (3 ÷ 12) = 6 ft³ = 0.22 yd³

L-Shape

An L-shaped area calculated as a full rectangle minus a rectangular cutout.

Volume = (Total Length × Total Width − Cutout Length × Cutout Width) × Depth
Example: An L-shaped path, 20×15 ft overall, minus a 10×8 ft cutout, at 4" deep
Volume = (300 − 80) × (4 ÷ 12) = 73.33 ft³ = 2.72 yd³

Waste Factor

The waste factor is applied as a percentage increase on the base volume.

Adjusted Volume = Base Volume × (1 + Waste% ÷ 100)
Example: 2.96 yd³ with 7% waste
Adjusted = 2.96 × 1.07 = 3.17 yd³

Weight Conversion

Weight is calculated by multiplying the waste-adjusted volume by the material density.

Weight (tons) = Volume (yd³) × Material Density (tons/yd³)

Weight (tonnes) = Volume (m³) × Material Density (tonnes/m³)
Example: 3.17 yd³ of gravel at 1.40 tons/yd³
Weight = 3.17 × 1.40 = 4.44 tons

Truck Loads

The number of dump truck loads is calculated by dividing total volume by truck capacity, rounded up.

Truck Loads = ⌈ Total Volume ÷ Truck Capacity ⌉

Default truck capacities: 10 yd³ (imperial) or 7.6 m³ (metric). You can change this in Settings.

Unit Conversions

1 cubic yard = 27 cubic feet
1 cubic foot = 0.0283168 cubic metres
1 cubic metre = 1.30795 cubic yards

All calculations are performed in cubic feet internally, then converted to cubic yards or cubic metres for display.

Frequently Asked Questions

How accurate are the calculations?

The formulas use standard geometry — the same maths your landscape supplier uses. The accuracy depends on how precisely you measure your site. Always use the waste factor to account for real-world conditions like uneven ground and compaction.

Why does the app calculate weight as well as volume?

Many landscape suppliers sell materials by weight (tons) rather than volume (cubic yards). GravelCalc converts between the two using accurate material densities so you can compare quotes and order the right amount regardless of how your supplier prices their product.

What depth should I use?

It depends on the material and application. Check the Recommended Depths table in the Reference tab for guidance. As a general rule: 2–4 inches for gravel driveways and paths, 2–3 inches for mulch, and 4–6 inches for topsoil in garden beds. The app pre-selects a recommended depth when you choose a material.

What waste factor should I use?

7% is the standard recommendation for most jobs. Use 5% for simple flat areas, 10% for slopes or irregular shapes, and 15% for areas where compaction is expected. When in doubt, go higher — having a small surplus is far better than running short.

Can I change between metric and imperial?

Yes. Tap the gear icon on the Calculator tab to open Settings, then switch the Unit System. The app defaults to the measurement system used in your country, but you can change it at any time.

Is my data saved?

Yes. Your project, cost settings, and preferences are saved automatically on your device. They persist between app launches. If you have iCloud backups enabled, your data is included in those backups. We never send your data to any server.

Does the app work offline?

Yes, 100%. GravelCalc works entirely offline with no internet connection required. Use it on-site, in the yard, or anywhere you have your phone.

Can I calculate multiple materials in one project?

Yes. Each calculation you add to the Project tab tracks which material it uses. You can have gravel for the driveway, mulch for the beds, and topsoil for the lawn all in one project with separate and combined totals.

The app is crashing or not working correctly

Make sure you are running the latest version of the app and iOS. Try closing and reopening the app. If the problem persists, contact us at the email below with a description of the issue and your device model.

Contact Support

Cannot find the answer you need? We are happy to help. Email us at support@top7systems.net and we will typically respond within 48 hours.

When reporting a bug, please include:

  • Your device model (e.g. iPhone 16 Pro)
  • Your iOS version (found in Settings > General > About)
  • A description of what happened and what you expected