Bathroom calculator - from the room dimensions to a finished offer
The client asks how much the bathroom will cost. You measure on site, do the math on your phone, copy it into Excel. Somewhere between the third wall and the grout, a difference of two square meters creeps in. It will not come to light until the job is finished.
Then it goes the way it usually goes. The tiles run out a day before the end and that batch is no longer available. The labor for cutting around the outlets is missing from the offer, because it does not show up in the measurements. And the client remembers the number you gave him over the phone.
The bathroom calculator does that take-off for you. In minutes, and the same way every time.
Quantity Surveys
Projects / Quantity Surveys
Total
6
Total Value
967,709.38 €
Contracts
3
Average Value
161,284.90 €
It all starts from the list of bills of quantities. The button sits next to "Import from IFC" - both produce a bill, only from a different input.
Step 1: you walk the walls
Most take-offs start with two numbers - length and width. Then come the boxed-in riser in the corner, the concealed cistern, the shampoo niche, the chamfered corner by the door. Each of them gets worked out in your head, and that is exactly where the square meters go missing.
Here you enter every wall with its length. After it you say which way the outline turns: inward, outward or at an angle. The door is marked on its own wall with two buttons - "Door" and "Window" drop in ready dimensions that you then adjust.
What this solves. The riser stops being a separate question. It is simply a stretch of the perimeter with two external corners. The same goes for the niche, for the shower kerb and for the bath apron. Every external arris enters the take-off as an edge that has to be closed with a profile or cut at 45 degrees.
If you have missed a wall, the calculator does not stay quiet. It says how much is left and along which axis.
Step 2: the areas come out on their own
As soon as the outline closes, six numbers appear at the top: floor, perimeter, walls net, external corners, wall above the tiling and the derived waste.
This is where you see why the machine counts better than we do. The shower kerb takes part of the floor, so the floor is not length times width. The niche and the cistern boxing add reveals to the walls and cover part of them. The door is deducted. These are all small calculations that get done in your head on site, and get done wrong.
Why it is built this way. You measure what you can see - walls, niches, kerbs. You do not measure areas. Areas are a result, not an input.
Step 3: you pick the tile and the scope
After the areas come the decisions:
- the size of the floor tile and of the wall tile
- the width and depth of the joint and the density of the grout
- the number of outlets in the walls
- how far the waterproofing goes
- what the ceiling is
- how the external corners are closed
- whether the substrate needs preparation
What this solves. Every choice shows or hides whole rows in the take-off. A bathroom tiled up to the ceiling has no row for painting above the tiling.
Choose a corner profile and you get the profile and its fitting. Choose a cut at 45 degrees and you get the labor for the cutting. More tiles break with it, and the ordering quantity goes up.
Grout density is a field too, not a fixed value. Cement-based grout sits around 1700, epoxy around 1500, and with a quartz filler it goes past 1800. Get it wrong and the error comes out in kilograms.
Step 4: the niches, the kerbs and the fittings
The niche, the boxing for the concealed cistern, the shower kerb and the bath apron are entered with their three dimensions and a count. The sanitary ware and the electrics take a count only: toilet, washbasin, mixers, shower cabin, floor drain, socket, light fitting.
What this solves. Built structures and installation work are small rows that look insignificant one by one, but added up they make the difference between a profit and working at a loss. The fitting itself stays out of the take-off unless you choose an item for it. The calculator does not decide for you whether you are selling the sanitary ware or only installing it.
Step 5: the item for each position
For every row the calculator suggests an item from your catalog, matched by name and unit of measure. The choice is remembered for next time.
Why it is not automatic all the way. Automatic matching picks the closest thing by name. When the catalog genuinely does not hold the item you need, the closest thing is sometimes the opposite in meaning - "installation" instead of "removal". That is why the choice stays in front of you and can be changed on the spot.
There is a safeguard as well: if you put in an item measured in square meters where the work is paid by the meter, the error surfaces straight away. Not as a tenfold quantity in the finished offer in front of the client.
Step 6: two quantities, two different purposes
Every position comes out with two numbers.
For certification is exactly what covers the surface.
For ordering is the first number plus what will end up in the bucket when the tiles get cut. How much that is depends on four things: the tile size, the size of the room, the laying pattern and the corner treatment. A large format in a narrow bathroom gets cut far more than a small one in a wide bathroom.
Which of the two goes into the take-off is not your choice. It follows the way the work is paid for:
- Labor is counted on the certified quantity. Laying sixteen square meters of wall is sixteen square meters, no matter how many tiles broke during the cutting.
- Material is counted on the ordered quantity. You pay for the tiles you bought, not for the ones that stayed on the wall.
Profiles carry a third rule: they are sold in bars. Needing 6.40 meters with a bar length of 2.50 means three bars, that is 7.50 meters paid for. So the row for the profile shows 6.40 for certification and 7.50 for ordering.
Adhesive and grout have their own consumption rates and do not follow the tile. Grout is not worked out per square meter at all. It comes from the tile size and the joint width. A large tile means few joints, a small one means many.
Why not a single number. Because the two serve different people. One goes to the client, the other to the supplier. Merged into one, you either certify more than you built or order less than you need.
Step 7: the positions go into the bill of quantities
The calculated rows go straight into the bill of quantities or into the offer, with quantities and prices. No re-typing, no second file.
The button sits in two places: in the positions toolbar while you are writing the bill, and in the list of bills of quantities, for when you start straight from the bathroom.
Run the calculator once more and it says how many of its rows the bill already holds, then asks you: add the new ones to them, or replace them.
Not just the tiles
A bathroom job replaces far more than the tiling. These are exactly the works that most often stay out of the offer:
- Waterproofing - the area, the tape along the cove between floor and walls, the collars around the outlets, with a choice of how far the wet zone reaches
- Ceiling - painting, a suspended plasterboard ceiling or panels
- Stripping out the old - tiling, screed, sanitary ware, plus removing the debris
- Preparation - leveling the floor and the walls before anything gets stuck down
- Built structures - niche, boxing for the concealed cistern, shower kerb, door threshold, bath apron
- Sanitary ware and electrics - the installation of each fitting separately
The labor that disappears from offers
Material is the easy part. The profit is usually lost in the labor, because labor does not show up in the measurements.
The take-off gets a separate row for each operation: laying the floor, laying the walls, tiling the reveals around the door, fitting the profiles, cutting at an angle, core drilling the tiles around the outlets.
Each of them carries its own price and its own unit. Some are paid per square meter, some per meter, some per piece.
For a company that is only just starting
There is no setup. The catalog is ready from day one: over a thousand items with indicative prices, including every material and every service the calculator uses. Your first offer can go out on the day you register, and the prices become yours as soon as you have your own.
What is left for you
Both quantities are stored on every row, but for now they are only visible inside the calculator itself. A separate column in the bill, in the export and in the printout for the supplier is still to come.
The calculator does not order in whole packs either. If the tile is sold in a box of 1.44 square meters, you will get 3.47 square meters, not three boxes. Profiles are the exception - they are bought in bars, and that is already counted.
It does not decide whether there is a bathtub or a shower, where the drain runs or what the bathroom should look like. It works out what you have decided.
And it does not replace the site visit. A wall out of plumb and a floor that drops two centimeters only show up on site.
If you are only just getting into the subject, start with the guide to preparing a bill of quantities.
Frequently asked questions
Why is the ordering quantity larger than the certification quantity?
Certification pays for exactly what covers the surface. Ordering adds what ends up in the bucket when the tiles get cut. The allowance depends on the tile size, on how big the bathroom is, and on the way the corners are closed. In the bill of quantities, labor follows the certified quantity and material follows the ordered one, because that is how each of them is paid for.
How do you describe a bathroom that is not rectangular?
You enter the walls in the order you walk them. After each one you say which way the outline turns - inward, outward or at an angle. The angles have to add up to 360 degrees. If the outline does not close, the calculator shows how much is left and along which axis, so you can find the wall you missed.
Do I have to fill in my nomenclature catalog first?
No. Every new company gets a ready catalog with over a thousand items and indicative prices. It covers every material and every service the calculator uses. The prices can be changed at any time.
Is it only for tiles?
No. It also works out the waterproofing, the ceiling, stripping out the old finish, substrate preparation, the niches, the kerbs, the bath apron, fitting the sanitary ware and the electrics. Each part is switched on or off separately.
What happens if I run the calculator twice?
If the bill of quantities already holds rows from the calculator, it says so and gives you a choice: add the new rows to them or replace them. You cannot double the bill without asking for it.