Concrete

Concrete calculator

Estimate one or more concrete pours, with shape, waste, ready-mix, bag and visitor-entered cost planning.

Transparent formulaFormula v1.0 · selected pour sections × waste allowance; optional bags, loads and visitor-entered costs

01Enter your measurements

Enter measurements, then review the audit trail before you buy.

Units

Pour sections

Add every separate slab, trench or circular pour to total the material requirement.

Pour section1

Pour shape

Length m

Width m

Finished depth m

Order options

Waste allowance %Extra material for cuts, breakage or handling. Enter 8 for 8% extra; use 0 for none.Bag yield

Ready-mix loads and cost planning

Optional planning inputs only. Enter a price from your own supplier discussion; Calculator.Shop does not provide prices.

Ready-mix load size m³ optionalLeave blank if you do not want a load estimate.Your ready-mix price £/m³ optionalOnly a price you enter is used.Your bag price £ per bag optionalOnly a price you enter is used.

02Materials estimate

Enter measurements to calculate.

Calculated requirement → waste allowance → recommended order → purchasable units

Calculated requirement—

Waste allowance—

Check supplier pricing

Supplier pricing is being prepared. Create the list first, then use it to ask a local merchant for price, stock, delivery and lead time. No contact details or measurements are sent.

Next steps

Product options · Not connected

Buy what you need

Use the ready-mix or bag requirement with a supplier. No product catalogue is connected.

Compare merchants · Not connected

Compare merchants

Enter a price only if you have one; Calculator.Shop does not supply merchant pricing or stock.

Professional quote option · Not connected

Get professional quotes

Create a quote-ready list. Calculator.Shop does not route or issue professional quotes.

Scope boundary: Materials estimate only — not for foundations, footings, load-bearing work or structural design.

Check the path

Your calculation audit

Every total is shown as a short sequence so you can see what was measured, deducted, adjusted and rounded.

01
Awaiting valid measurementsComplete the fields above to reveal the formula path.
—

Measure clearly

Simple guidance

Add each separate pour once. Use length × width × finished depth for rectangular slabs or trenches, or diameter × depth for a circular pour. The tool totals every section before applying the visible allowance.

Measure the finished surface or internal clear dimensions. Keep a note of any deduction you make.

Worked example

Follow the same logic

A 3 m × 2 m slab at 100 mm deep is 0.6 m³ before a selected allowance. Add a separate trench or circular section when it is part of the same material plan; bags and ready-mix loads round up only after the total.

Planning tipWrite down the product factor or pack size you used, so a later change is easy to trace.

Before you buy

Three quick checks

01
Add each separately measured slab, trench or circular section once.
02
Use the intended finished depth for every section.
03
Check the bag yield, ready-mix load size and any price with the supplier before buying.

Quick answers

Useful to know

Can I mix shapes in one calculation?

Yes. Add each slab, trench or circular pour as its own section; the result is the sum of those measured volumes plus the allowance you selected.

Can I use the cost fields as a quote?

No. They only multiply a price that you enter by the calculated quantity. Calculator.Shop does not supply a price, stock position or quote.

Review record

Transparent calculation method

Last reviewed: 2026-10-17. Formula version: v1.0. Classification: concrete volume estimate; not specialist design.

Formula source: src/calculator-core.mjs#concretePlan. Shapes, bag yield, load size and any pricing are selected or entered by the visitor.

Read methodology