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Construction Calculators

Concrete, gravel, sand, brick, and cost tools for slabs, pads, footings, and masonry — with formulas and worked examples on every page.

7 calculators

Construction calculators on Project Home Calc turn length, width, and depth into order quantities you can take to a ready-mix plant, bag aisle, or gravel yard. They are planning tools — not structural designs — so every result sits next to the formula and a worked example you can re-run with your own numbers.

What this category covers

Use these tools when the job is bulk material: concrete for slabs, pads, and footings; gravel or sand for bases and bedding; brick counts for short walls; and cost lines that convert volume into a planning price band. Most patio and driveway mistakes start with the wrong thickness or a missing sub-base, not with a fancy finish.

How to use the tools together

1. Size the pour or base with the Concrete or Gravel calculator. 2. Check bag counts on small jobs with the Concrete Bag tool when a truck minimum would dominate. 3. Price materials with the Concrete Cost or Gravel Cost calculators, then fold labour into the Cost Estimator if you need a full planning total. 4. Read a related guide when two quotes disagree on thickness, waste, or base depth.

Typical project paths

  • Patio or shed pad: concrete volume → gravel sub-base → cost range → patio cost guide.
  • Driveway base: gravel depth and tonnage before any surface layer.
  • Fence posts or small pads: bagged mix often beats a short-load truck — compare with ready-mix vs bags guidance.
  • Brick garden wall: brick count plus mortar allowance; confirm bond pattern with your mason.

Units and assumptions

Every tool supports US (feet/inches, yards, tons) and UK (metres/centimetres, cubic metres, tonnes) units. Switching units converts what you already typed. Waste percentages are editable defaults — irregular digs and decorative pours need more than a clean rectangle.

Depth is kept in inches or centimetres because that is how plans specify slab and base thickness. Mixing unit systems mid-quote is how homeowners “compare” two numbers that are not the same scope.

What these calculators do not include

Permits, frost-line footings, rebar schedules, soil reports, pump hire, spoil haul-away, and decorative finish premiums are usually separate lines. If a contractor’s number is far from your materials estimate, ask which of those items are included before you assume someone is overcharging.

Related reading

Browse the guides for patio cost, slab thickness, gravel driveways, waste factors, and ready-mix versus bags. Each article is written to sit next to these calculators so you can check a quantity and then understand why a quote moved.

Related guides

Guide

How Much Does a Concrete Patio Cost?

A practical breakdown of concrete patio pricing — volume, sub-base, labour, finish, and how to sanity-check a contractor quote.

Guide

How Much Gravel Do You Need for a Driveway?

Convert length, width, and depth into tonnes or cubic yards, plus a practical waste allowance for compaction and uneven ground.

Guide

How Much Mulch Do You Need for Garden Beds?

A clear method for bed area, depth, bags versus bulk delivery, and when to refresh an existing mulch layer.

Guide

How to Estimate Decking Boards and Framing Basics

Turn deck length and width into board count with gap spacing, and know what the board calculator does not include.

Guide

Patio vs Driveway Concrete Thickness

Why patio, shed, and driveway slabs use different thicknesses — and how thickness multiplies your concrete volume.

Guide

How to Compare Contractor Quotes Side by Side

Line up materials vs labour, allowances, and exclusions — use your own quantity checks against lump sums.

Guide

Why Patio Bases Need Gravel Before Concrete

How sub-base depth affects stability and how to estimate gravel and concrete as two separate material lines.

Guide

US and UK Units on the Same Project

Feet vs metres, gallons vs litres — keep one system per calculation so orders don’t go wrong.

Guide

How Many Bags of Concrete for a Slab?

Bag counts for common slab sizes — when bag mix makes sense and when to call the truck instead.

Guide

Planning a Paver Patio Base

Gravel sub-base, sand bedding, and paver counts — the three layers in order.

Guide

Fence Materials for a Straight Run

Panels, posts, and rails from a single fence length — before you buy the wrong kit.

Guide

How Much Topsoil Do You Need?

Turn bed or lawn measurements into cubic yards or metres — depths for new beds vs topdressing, bags vs bulk, and what topsoil calculators leave out.

Guide

Ready-Mix vs Bagged Concrete: Which Should You Order?

An honest break-even around one cubic yard — labour time, short-load fees, colour consistency, and when bags beat a truck for posts and small pads.

Guide

How Much Sand Do You Need for a Paver Bed?

Work out bedding-sand volume for patios and paths without confusing the thin setting bed with the compacted gravel base.

Guide

How Many Bricks Do You Need for a Garden Wall?

Estimate bricks from wall area, thickness, openings, piers, cuts, and waste, with worked examples for US and UK brick sizes.

Guide

How Much Concrete Do You Need for Fence Posts?

Calculate concrete per post hole, convert total volume into bags, and avoid common mistakes with hole shape, drainage, and gate posts.

Guide

Driveway Concrete Thickness and Cost

Choose a realistic driveway slab thickness, calculate concrete and base quantities, and build a cost estimate that includes more than the pour.

Guide

Mortar Quantities for Brickwork

Estimate wet mortar, cement, and sand for brick walls while accounting for brick size, wall thickness, joint profile, waste, and small batches.

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