Mortar Calculator for Bags, Mix & Mortar Volume
Calculate the mortar quantity for bricklaying, blockwork, masonry joints, pointing, bedding, rendering and screeding with practical measurements for area, thickness, joint size, material mix and waste.
Enter your project dimensions, mortar thickness or joint measurements, then choose the material supply method to calculate the mortar volume, bags, cement, lime, sand, water and estimated cost.
For a mortar calculation, measure the working area first. Enter the length and width for floors and horizontal work, or the length and height for walls. For brick or block laying, enter the masonry unit length, height and width together with the mortar joint width and wall thickness. For pointing, enter the joint width and rake-out depth. For bedding, render and screed, enter the bed depth, coat thickness or screed depth. The calculator accepts feet (ft), inches (in), metres (m), centimetres (cm) and yards (yd), while thickness can be entered in millimetres (mm), inches or centimetres.
This Mortar Calculator converts your measurements into the mortar volume required for the selected job. The calculation covers five common applications: mortar for laying bricks and blocks, masonry pointing, paving bedding, wall render and floor screed. The calculator determines the working area, mortar requirement and material quantity from the dimensions you provide rather than relying on a single fixed coverage rate.
For brickwork and blockwork, the mortar estimate uses the masonry unit dimensions and mortar joint to determine the module area, units per square metre and the portion of the wall occupied by mortar. For pointing, the joint length, joint width and rake-out depth determine the mortar volume. For bedding and screeding, area multiplied by thickness determines the base volume, while render uses wall area, coat thickness and the number of coats.
After the wet mortar volume is calculated, the selected waste allowance is added. Pre-mixed mortar can then be converted into bag quantities using the selected bag yield, while a cement-and-sand mix can be divided according to a selected cement : lime : sand ratio. The material calculation can include cement bags, hydrated lime, sand volume, sand weight and water requirements, with batch quantities based on the selected mixing method.
Mortar Calculator
What is the mortar for?
Unit size & joint
How is it supplied?
Cost estimate ($)
How the Mortar Calculator Works
The Mortar Calculator starts with your project area and the dimensions that control mortar demand. It calculates the required mortar volume, applies the selected waste allowance, then converts the result into pre-mix bags or cement, lime, sand and water quantities.
Choose the Job
Select laying, pointing, bedding, render or screed according to the work being completed.
Enter Measurements
Enter length, width or height, thickness, joint dimensions and masonry unit measurements where required.
Set Waste
Choose a waste allowance to cover practical material loss during mixing, handling and installation.
Choose Supply
Use pre-mix bags or select a cement, lime and sand mix with the required material ratio.
Read Results
Review mortar volume, material quantities, water, batches and optional project cost.
Mortar Calculator Formula
The formula changes according to the selected mortar application because bricklaying, pointing, bedding, rendering and screeding use different dimensions to determine mortar volume.
Mortar Calculator Example
A practical bricklaying example shows how the measurements work together before the calculator converts the mortar requirement into bags and other material quantities.
Brick Wall Mortar Calculation
Example using a 20 ft × 8 ft wall with a standard US modular brick.
The calculator determines the wall's mortar requirement from the masonry module, adds the 10% waste allowance, converts the final volume to 80 lb pre-mix bags using the 0.75 ft³ bag yield, calculates pallet quantity from 42 bags per pallet, and estimates water and mixing batches from the selected settings.
Helpful Information Before Calculating Mortar
Accurate mortar estimates depend on accurate dimensions, the correct mortar application and realistic material settings. Use the following points to prepare your measurements before calculating.
Measure the Working Area
Measure the actual wall, floor or paving area receiving mortar. Use length and height for walls, or length and width for floors and horizontal surfaces. The calculator accepts ft, in, m, cm and yd for project dimensions.
Measure Thickness Correctly
Enter mortar bed depth, screed depth, render coat thickness or pointing rake-out depth using mm, inches or cm. A small change in thickness can materially change the mortar volume.
Use Actual Masonry Dimensions
For brick and block laying, use the actual unit length, height and width rather than nominal descriptions alone. Joint width is part of the masonry module used to estimate units and mortar consumption.
Select the Correct Application
- Select Laying for brick or block masonry.
- Select Pointing for filling or replacing masonry joints.
- Select Bedding for a mortar bed beneath paving or units.
- Select Render for wall coating applied in one or more coats.
- Select Screed for a mortar-based floor screed layer.
Allow for Material Waste
Waste covers practical losses during mixing, handling and installation. The calculator allows a waste value from 0% to 40%, so use a percentage that reflects the conditions of the project rather than automatically selecting the maximum.
Choose the Right Mortar Supply
Select pre-mixed bags when the material is purchased as a ready-to-use dry mortar product. Select cement and sand when the mortar is site-mixed and enter the required cement, lime and sand ratio.
Understand Mix Ratios
A ratio such as 1:4 represents one part cement to four parts sand, while 1:1:6 represents cement, lime and sand. The calculator includes strong, standard, general, soft and lime-based ratio options.
Check Bag Yield
Pre-mix bag quantities depend on the yield assigned to the selected bag. A 60 lb bag, 80 lb bag, 25 kg bag and 20 kg bag do not necessarily produce the same mortar volume, so use the manufacturer's stated coverage or yield when available.
Review Water Requirements
Pre-mix calculations use the entered litres of water per bag. Site-mixed mortar uses the selected water-to-cement ratio (W/C) and calculated cement quantity. Actual water demand can vary with material moisture and product requirements.
Use Density for Sand Estimates
Site-mixed calculations use a selected sand density of 1.45, 1.60 or 1.75 t/m³. Dry, loose and damp sand can have different bulk densities, so choose the setting that best matches the material being measured.
Related Calculators
Use these related construction calculators to estimate quantities for other materials and stages of a masonry or home improvement project.
Frequently Asked Questions
These answers explain the measurements, formulas, material quantities and practical settings used by the Mortar Calculator.
What does a Mortar Calculator calculate?
A Mortar Calculator estimates the mortar volume required for laying, pointing, bedding, rendering and screeding. Depending on the selected supply method, the result can include pre-mix bags or cement, lime, sand and water, together with batch quantities and optional cost estimates.
How do I calculate mortar for a brick wall?
Select Laying, measure the wall length and height, then enter the brick length, height and width, mortar joint width and wall thickness. The calculator uses the masonry unit and joint dimensions to determine the module area, units per area and mortar portion of the wall.
What measurements do I need for a mortar calculation?
The required measurements depend on the job. Laying needs wall dimensions, masonry unit dimensions, joint width and wall thickness; pointing needs area, joint width and rake-out depth; bedding needs area and bed depth; render needs wall area, coat thickness and coats; screed needs floor area and screed depth.
Can I calculate mortar in cubic feet, cubic metres and litres?
Yes. The calculator displays mortar volume in cubic feet (ft³) and litres (L), while its internal calculations use cubic metres (m³). Project measurements can be entered in feet, inches, metres, centimetres or yards.
How many bags of mortar do I need?
The required number of bags depends on the final mortar volume and the yield of the selected bag. The calculator divides the required mortar volume by the selected bag yield and rounds the result up to a whole bag, so the quantity accounts for the selected waste allowance.
Does the Mortar Calculator calculate cement and sand?
Yes. Select Cement & Sand and choose a mortar ratio such as 1:3, 1:4, 1:5, 1:6, 1:1:6 or 1:2:9. The calculator applies the dry-volume factor, divides the dry volume according to the selected ratio and calculates cement, lime and sand quantities.
How much water is needed for mortar?
For pre-mixed bags, water is calculated from the number of bags multiplied by the entered litres per bag. For site-mixed mortar, water is calculated from the cement quantity multiplied by the selected water-to-cement ratio (W/C), such as 0.45, 0.50 or 0.55.
Should I add waste to my mortar calculation?
Yes, a realistic waste allowance is useful for material planning. The calculator applies the selected percentage to the calculated mortar volume, with an available range from 0% to 40%. The appropriate percentage depends on handling, site conditions, workmanship and material loss.
Can this calculator estimate mortar for pointing?
Yes. Select Pointing, enter the project area, joint width and rake-out depth. The calculator estimates joint length from the masonry module and then calculates mortar from joint length × joint width × rake-out depth.
Can I use the calculator for render and screed?
Yes. Render uses wall area, coat thickness and number of coats, while screed uses floor area and screed depth. Bedding uses the same area-and-thickness approach with the selected bed depth and compaction or key-loss setting.
Can I estimate mortar cost as well as quantity?
Yes. Cost is optional. The calculator supports pricing by bag, pallet, cubic yard, cubic metre, square foot or square metre, depending on the selected supply method and pricing mode. Cement, sand, lime, labour, mixer hire and delivery can be included where the corresponding fields are available.
Are the Mortar Calculator results exact?
No. The results are estimates for material planning. Actual mortar consumption depends on masonry dimensions, joint consistency, substrate conditions, material properties, workmanship, product yield, moisture and site waste. Confirm the final order quantity with the product manufacturer, supplier or qualified trade professional.