Material Calculator for Decorators
Calculate paint quantities, coverage and costs for any job. Accurate litres, coats and materials in seconds.
Calculating how much paint you need is error-prone. Too little and you run out mid-job. Too much and you have wasted money. Getting it right means understanding room dimensions, coverage rates and the number of coats.
The Trade Assist Material Calculator does all the maths for you. Enter the room dimensions and paint product, and it calculates exactly how many litres you need and what it costs.
Deep Dive: Material Calculator
Material calculation is the part of quoting where most errors occur. Get it wrong and you either run out of paint mid-job — an embarrassing and costly mistake — or you over-order and tie up money in paint you do not need. The maths is not difficult, but it is tedious, repetitive and easy to get wrong when you are quoting five jobs in an evening.
The Trade Assist Material Calculator removes the guesswork and the maths. Enter the room dimensions and your paint product's coverage rate, and the calculator works out exactly how many litres you need, accounting for the number of coats, the surface area and any deductions for doors and windows. It is fast, accurate and consistent — every time.
What makes the calculator particularly valuable is its consistency. When you calculate paint quantities by hand, you might round up generously one day and tightly the next. The calculator applies the same logic every time, so your material costs are consistent across every quote. This consistency is what allows you to compare quotes, identify pricing anomalies and build a reliable pricing model for your business.
The calculator also handles the surfaces that are easy to forget. Skirting boards, door frames, window reveals, radiators — all of these need paint, and all of them are easy to miss when you are doing a quick quote. The calculator lets you add extra surfaces to each room, so every paintable area is accounted for and every cost is captured. No more undercharging because you forgot the woodwork.
See Material Calculator in Action
Watch a 2-minute demo of how material calculator works in Trade Assist
Start Free TrialKey Benefits
Accurate quantities
No more guessing. Calculate exactly how many litres you need for any room.
Save money
Avoid over-ordering paint and materials. Buy exactly what you need.
Save time
Let the calculator do the maths. Get accurate figures in seconds.
Features
Room area calculator
Enter dimensions and get wall area, ceiling area and total paintable surface.
Paint coverage
Enter your paint's coverage rate per litre and get the exact litres needed.
Cost calculation
Enter the price per litre and see the total paint cost for the job.
Coat calculation
Specify the number of coats and the calculator adjusts the quantities automatically.
How It Works
Enter room dimensions
Input the length, width and height of the room.
Choose your paint
Enter the coverage rate and price per litre for your paint product.
Get your quantities
The calculator shows litres needed, cost and total area — instantly.
Frequently Asked Questions
How accurate is the calculator?
The calculator uses your paint's actual coverage rate and the room's real dimensions, so the figures are as accurate as your inputs.
Does it account for multiple coats?
Yes. Specify the number of coats and the calculator adjusts the paint quantity accordingly.
Can I calculate materials for multiple rooms at once?
Yes. Add as many rooms as you need to the calculator. Each room is calculated individually and the totals are combined, giving you the total paint and material requirements for the entire job.
Does it account for different paint types and coverage rates?
Yes. Enter the specific coverage rate for your paint product — different paints have different coverage rates per litre. The calculator uses the actual coverage rate, not a generic assumption, so your quantities are accurate for the specific product you will use.
Can I calculate materials for non-paint surfaces?
Yes. The calculator supports additional surface types — doors, skirting, floors and custom surfaces. You can enter the area, number of coats, paint product and price per litre for each, so all material costs are captured.
Can I save my default paint products and coverage rates?
Yes. Save your commonly used paint products with their coverage rates and prices per litre as defaults. This speeds up every quote and ensures your calculations are based on accurate, up-to-date product information.
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