Floor Screed Calculator – Volume, Bags, Sand, Cement & Cost

The Handyman Hub • Free Calculator

Floor Screed Calculator

Estimate screed volume, traditional sand and cement, bagged screed or ready-mix requirements across multiple floor areas. Add costs and optional job pricing only if you need them.

1. Project Setup

Choose your measurement system and currency. Currency changes symbols only and does not convert prices.

2. Screed Type

Select how the screed will be supplied. The relevant material settings will appear below.

3. Floor Areas

Add each room or section separately. Every area can have a different shape and screed thickness.

4. Waste / Extra Allowance

Add an allowance for minor level variations, handling losses and site conditions.

%
Underfloor heating is for guidance only. Required screed depth and cover over heating pipes varies by screed system, project specification and manufacturer. Your entered screed thickness remains the calculation basis.

5. Traditional Sand & Cement

Choose a cement : sand ratio, cement bag size and how you intend to purchase sand.

1 : value
kg
£
£ / tonne
£ / m³
kg
£
Advanced Material Assumption
kg / m³
Default reference basis is 1,890 kg/m³. Actual project mix designs can vary, so use a specified mix design where available.
Mix ratios are provided for estimating only. Do not assume one ratio or material model is suitable for every bonded, unbonded, floating, heated or proprietary screed specification.

5. Premixed / Bagged Screed

Use the manufacturer's yield or coverage wherever possible. Bagged products can vary significantly in density and formulation.

kg
m³ / bag
m²
mm
kg/m²/mm
£
Manufacturer coverage should be used whenever available because bagged screed products vary in density, formulation and yield.

5. Ready-Mix / Loose Screed

Price the adjusted volume directly. Minimum order and order increment are optional supplier-specific fields.

£ / m³
m³
m³
Leave at 0 if your supplier accepts any volume.

6. Optional Job Pricing

DIY users can leave this entire section at zero. Labour methods are mutually exclusive to prevent double-counting.

£
£
£
£
£
%
%
Thickness is user-controlled. Follow the project specification, applicable standards and screed manufacturer's instructions. This calculator estimates quantities and costs; it is not a structural design tool.
Your screed results will appear here Complete the calculator above and select Calculate Screed Requirements.
The Handyman Hub • Calculation Results

Floor Screed Estimate

Area & Volume Breakdown

Area Shape Floor Area Thickness Screed Volume

Material Requirements

Cost & Job Pricing

How This Is Calculated

Rectangle Floor area = Length × Width
Circle Floor area = π × radius²
Triangle Floor area = Base × perpendicular height ÷ 2
Screed Volume Floor area × screed thickness
Adjusted volume = Base finished screed volume × (1 + Waste / Extra %)

Important Screed Guidance

Screed thickness remains user-controlled. Bonded, unbonded, floating and heated floors, conventional cement screeds and proprietary screed systems can all require different thicknesses and specifications. Follow the project design, applicable standards and the screed manufacturer's instructions.
Estimate only: This calculator is intended for quantity, purchasing and cost planning. Actual yields, densities, moisture conditions, compaction, substrate levels, installation methods and manufacturer requirements can alter real material consumption. Confirm quantities and specifications before ordering.
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How to Use the Floor Screed Calculator

This free floor screed calculator helps estimate the amount of screed required for floors using traditional sand and cement, premixed bagged screed or ready-mixed screed. It can calculate several floor areas in one project, even when those areas have different screed thicknesses.

Enter the dimensions of each floor area and the required screed thickness. The calculator works out the finished screed volume before adding your chosen waste or extra allowance. For traditional screed it can also estimate cement bags and sand requirements, while bagged screed can be calculated using the manufacturer's stated yield or coverage.

Tradespeople can also add material prices, labour, delivery, equipment and other costs to produce an estimated project cost and selling price. DIY users can simply leave the optional pricing section at zero and use the calculator purely as a material estimator.

Calculating Floor Screed Quantity

The basic screed calculation starts with the floor area. For a rectangular floor this is length × width. The area is then multiplied by the required screed thickness to determine the finished screed volume.

Rectangle Length × Width
Circle π × Radius²
Triangle Base × Perpendicular Height ÷ 2
Screed Volume Floor Area × Screed Thickness

The calculator allows every floor area to have its own thickness. This is useful for jobs involving different rooms, extensions, repairs or floors where screed levels vary across the project.

Important: Do not choose a screed thickness simply from an online calculator. Appropriate thickness depends on the screed system, substrate and floor construction. Always follow the project specification and screed manufacturer's instructions.

Traditional Sand and Cement Screed

Traditional floor screed is commonly produced from cement and sharp sand. This calculator allows you to choose different cement-to-sand ratios, including custom ratios, rather than assuming that one mix is appropriate for every floor.

The calculator uses an editable reference dry-material quantity to estimate the amount of cement and sand needed for the finished screed volume. It then divides the material requirement according to the selected mix ratio.

Cement is converted into complete purchase bags rather than displaying an unrealistic fraction of a bag. Sand can be estimated by weight, loose volume or bulk bags depending on how your supplier sells it.

Why is there a waste allowance?

Real floors are rarely perfectly uniform. Minor level differences, handling losses, mixing losses and site conditions can mean slightly more screed is required than the theoretical finished volume. The calculator therefore includes an editable waste or extra allowance rather than automatically assuming a fixed amount.

Premixed and Bagged Screed Calculator

Premixed screed products can vary considerably in density, formulation and coverage. For that reason, this calculator does not assume that every bag produces the same amount of finished screed.

Where possible, use the yield, coverage or consumption figure supplied by the manufacturer. Enter that information into the calculator together with the bag size and it will estimate the theoretical number of bags required before rounding up to whole purchase bags.

Manufacturer data should take priority over generic online coverage estimates for proprietary or premixed screed products.

Ready-Mixed Screed Volume

If screed is being supplied loose or ready mixed, the calculator can provide the adjusted order volume in cubic metres when using metric measurements or cubic yards when using imperial measurements.

Supplier minimum orders and delivery increments can also be entered. Unless you specify one of these restrictions, the calculator does not arbitrarily round the volume upward.

Floor Screed Calculator FAQs

How do I calculate how much floor screed I need?
Calculate the floor area and multiply it by the required screed thickness. For example, a rectangular floor uses length × width to find its area. The calculator performs these calculations automatically and can then add a waste or extra allowance.
How many bags of screed do I need?
This depends on the manufacturer's stated yield or coverage for the particular product. Enter the manufacturer's figure into the premixed screed section and the calculator will estimate the theoretical number of bags and then round it up to whole purchase bags.
How much sand and cement do I need for screed?
The amount depends on the screed volume and the cement-to-sand mix ratio. Select the required mix ratio in the traditional screed section and the calculator will estimate cement and sand quantities separately.
What cement-to-sand ratio should I use for floor screed?
There is no single ratio suitable for every screed installation. The required mix can depend on the specification, floor construction, strength requirements and screed system. Use the ratio specified for your project rather than relying on a generic recommendation.
How thick should floor screed be?
Screed thickness varies according to whether the screed is bonded, unbonded or floating, the floor construction, intended use, presence of underfloor heating and the type of screed being installed. This calculator deliberately allows you to enter the required thickness rather than prescribing one.
Can I calculate screed for underfloor heating?
Yes. Enter the screed thickness specified for the particular underfloor-heating system and floor construction. The calculator does not automatically increase the thickness because required cover varies between systems and products.
Should I add extra screed for waste?
An extra allowance can help account for small variations in floor levels, handling and installation losses. The calculator starts with a 5% editable allowance, but the appropriate amount depends on the actual project and site conditions.
Does the calculator work in feet and inches?
Yes. Select Imperial in the calculator to enter floor dimensions in feet and screed thickness in inches. Results are converted consistently using the calculator's internal metric calculation system.
Can I calculate several rooms at once?
Yes. Add multiple floor areas and give each one its own dimensions, shape and screed thickness. The calculator calculates each section separately before combining the quantities into the total project requirement.
Is this floor screed calculator free?
Yes. The Floor Screed Calculator is free to use with no email address, account, subscription or payment required.

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Separate screed thickness from the finishing layer

Use the measured area and the specified screed thickness for each floor zone. Keep the selected supply method visible: a ready-mixed volume, a bagged product yield and a traditional mix require different purchasing information. A quantity estimate does not choose the floor construction or drying period.

For a separate smoothing product use the self-levelling compound calculator. The DPM and vapour barrier calculator and insulation calculator cover specified layers beneath or within the floor assembly. Allocate a thickness to each layer rather than counting the full build-up as screed.