Fields, items, formulas and calc sheets

Open Calculate Quantity on any BOQ item and you choose one of five sources for its quantity. This article covers all of them in detail, and the two things that happen to the number afterwards.

If you only want to know which method to reach for, read Getting a quantity instead — it is the short version.

The window

The five methods run down the left, each showing what it would give; the one in use is marked. Whatever the method produces, the strip along the bottom shows it turning into the quantity and the total — here 179.84 rounded up to 180 m2, and $11,700.

The window has three parts:

• Get the quantity from, down the left: the five methods. Each one shows what it would give right now, and the one the item uses carries an In use tag.
• The middle: the method you are looking at.
• Adjust, under the methods: wastage, item size and rounding.

Along the bottom, the quantity bar works the answer out step by step before you save: what the method gives, then wastage, then the size, then the rounding, ending in the quantity the BOQ will show. Save only when that last number looks right. Ctrl+S (Cmd+S on a Mac) saves too.

If you are allowed to see costs, the bar ends with the Total: the quantity times the item’s price, as the BOQ’s Total column works it out, and how much more or less that is than now. A switched-off item says so, because it adds nothing to the job.

When other items take their quantity from this one, a line above the bar names them: “3 other items change with this quantity: Concrete supply, Mesh, Vapour barrier.” Show all lists every one, including items further down a chain (an item that follows an item that follows this one) and formulas that use it. Change a slab from 180 to 150 m² and you can see which lines move with it before you save. After you save, those lines update in the BOQ straight away.

On a narrow screen the methods become a row you scroll sideways, and the adjustments move under the middle part.

The five methods

Button	Quantity comes from	Follows changes
Manual	A number you type	No
Take-off field	A take-off measurement	Yes
Another item	Another item in this estimate	Yes
Calc Sheet	Dimensions entered as rows	Recalculates from the rows
Formula	An expression over named variables	Yes

An item uses one method at a time. Switching method does not erase the others — a calc sheet you built stays there if you switch to Formula and back — but only the one showing when you press Save quantity produces the quantity. The line at the bottom says so when you are about to switch (“Saving switches this item from Manual to Calc Sheet”).

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Field

The fields are grouped by the assembly they belong to, with what each one currently measures. Measure on the plan is the other way in: it opens Take-Off to measure this item onto a drawing, and the quantity then follows that.

Calculate quantity using a field. The quantity comes from a take-off field, so it follows every measurement you make on the drawing.

Pick a field from the list: fields are grouped under their assembly, each shows its current total, and the search box narrows the list as you type. The item’s quantity becomes that field’s total.

Measure on the plan

The button at the bottom of this tab opens Take-Off with this item in mind.

Measure into an existing field or create a new one, press Done, and the item comes back already pointed at what you measured. It saves doing the two halves — measure it, then price it — as separate errands.

What to know

• A field’s total is read live. Change a measurement and the item is already right; there is no recalculation to run.
• One field can feed many items. Measure the slab once and point the concrete, the mesh, the membrane and the sand bed at it.
• A field that gets its quantity from a formula is read-only in Take-Off. The formula wins; clear it if you want to measure the field off a drawing instead.
• If the field’s unit does not match the item’s (m² of slab feeding m³ of concrete), a yellow warning says so and shows what the item would be priced at. See When a quantity looks wrong.

See Take-off fields and the BOQ for how fields, units, heights and depths work.

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Item

Every item in the estimate, under its cost code. The item you are working on is greyed out and marked This item, and anything switched off says so — a quantity that follows a switched-off item counts as nothing.

Calculate quantity using the quantity of another item in this estimate. This is the one people miss, and it removes a lot of duplicated measuring.

Pick the item from one list: every item in this estimate, grouped by cost code, each with its quantity. Type in the search box to find it by name or cost code.

The item itself is greyed out, and so is any item that already follows this one — linking the two would make each wait for the other forever.

With or without its wastage

Once you have picked the item, choose how much of it to take:

Choice	Takes	Example: slab 180 m², 10% wastage
With its wastage	Its final quantity, as the BOQ shows it	198 m²
Without its wastage	Its own quantity before its wastage is added (its size and rounding still apply)	180 m²

Both numbers are shown on the two choices, so you can see the difference before you pick.

Take it without its wastage when this item carries its own allowance. Concrete that follows the slab area, with the concreter’s 5% on the concrete item, should not also pick up the slab’s 10%: that would count waste twice.

Take it with its wastage when this item really follows what will be bought or laid — the fixings for the sheets you will actually order, say.

Duplicating the item, or the whole estimate, keeps the choice.

When to use it

Whenever one item’s quantity genuinely is another’s:

This item	Takes its quantity from
Mesh chairs	The mesh
Bedding sand	The slab area
Paint, second coat	Paint, first coat
Skirting adhesive	Skirting
Door furniture	Internal doors

It is faster than a formula when the relationship is one-to-one, and it survives being re-measured because it reads the source item rather than a copy of it.

The source item must stay switched on

If the item you are borrowing from is switched off, this item’s quantity becomes zero — silently. Nothing warns you.

That bites when you carry options: switch off the tiled roof in favour of colorbond, and anything that took its quantity from a tiled-roof item quietly drops to nothing. If you price options this way, check what depends on them before switching.

Chains

The source item can itself take its quantity from a field, a formula or another item, and it all resolves. Measure the slab once, let the concrete read the field, and let the pump read the concrete.

Keep chains short. Two links is easy to follow; five is a puzzle when a number looks wrong six weeks later.

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Formula

Take-off fields become lettered variables, and the sum is written with the letters. The result updates as you type, so you can see the answer before saving.

Calculate quantity using the Formula. The quantity is an expression over named variables you define on the item.

The tab has three parts: the variables, the formula box, and its result.

Button	Does
Add variables	Opens a window listing the job’s take-off fields and items. Press Add as A, Add as B and so on beside each one you need, then Done
Sum all	Writes {A} + {B} + {C}… using every variable
⋯ › Copy variables and formula / Paste	Moves the set to another item in the same job
⋯ › Remove all variables…	Clears them, after asking

Each variable gets a letter in the order you add it, and its row shows where it comes from and its current value. A variable that is another item also shows that item’s description under its name, so two items with similar names are easy to tell apart (hover over it for the full text). The Add variables window and the From another item list show the description too, and their search boxes find words in it. Click a letter — or the Insert buttons under the box — to put it into the formula where the cursor is.

The Result box works the formula out as you type, the same way the save will, and says what is wrong when it cannot: a letter that is not in the list, a bracket out of place. That check is worth reading — a formula that produces 1,864 instead of 18.64 looks entirely plausible sitting in a total.

Writing one

Ordinary arithmetic over the letters: +, −, × (*), ÷ (/) and brackets.

Item	Variables	Formula	Reads as
Slab mesh	A = slab area	{A} * 1.05	Slab area plus 5% laps
Slab concrete	A = slab area, B = slab depth	{A} * {B}	Area × depth
Wall paint	A = wall length, B = wall height	{A} * {B} * 2	Both faces
Skirting	A = wall length, B = door openings	{A} - {B}	Wall run less the doors

Functions

The Functions buttons under the formula box insert one with the cursor inside its brackets. Select part of the formula first and the button puts that part inside the brackets instead: select {A} * 1.1, press CEILING, and you get CEILING({A} * 1.1). Hover over a button to see what it does.

Function	Gives	Example
IF(condition, then, else)	One answer or the other	IF({A} > 100, {A} * 1.1, {A})
CEILING(x)	Up to the next whole number	CEILING(4.2) = 5
FLOOR(x)	Down to the whole number	FLOOR(4.8) = 4
ROUND(x, places)	To the nearest, to that many decimal places. A minus number of places rounds to tens, hundreds…	ROUND(2.345, 2) = 2.35
MIN(a, b)	The smaller of the two	MIN(3, 5) = 3
MAX(a, b)	The larger of the two	MAX(3, 5) = 5
ABS(x)	Without its minus sign	ABS(-2) = 2
SQRT(x)	Square root	SQRT(16) = 4
POWER(x, n)	x to the power n	POWER(3, 2) = 9

CEIL works as another name for CEILING. (CEIL, MIN and MAX used to make a formula fail and give a quantity of 0. They now work.)

IF gives one answer when something is true and another when it is not — a quantity that only gets a margin added over 100, say. The IF button puts in IF( > , , ); select {A} first and it becomes IF({A} > , , ) with the cursor ready for the number.

• Compare with > < >= <= = <>, and join conditions with AND and OR — IF({A} >= 10 AND {A} < 20, …). AND is worked out before OR.
• Once the formula has an IF in it, a row of In an IF buttons appears with those signs, so there is nothing to remember.
• IFs can sit inside each other and inside the other functions: MAX(IF({A} > 50, {A}, 0), 3).
• A comparison only works inside an IF, and each answer must be a number.

Whole numbers divide as whole numbers

3/10 gives 0, not 0.3: when both sides are whole numbers the division drops the remainder. Write 3.0/10 or 0.3. The Result box shows exactly what will be saved, so this shows up before you save.

Removing a variable

The letters after it move up — remove A and B becomes A — and the formula is re-lettered to match, so it keeps pointing at the same things. Anywhere the removed one was used shows as {?} and the Result box says so, rather than quietly reading a different variable.

Copy and paste variables

Copy and paste are what make formulas practical across a bill. Set up the variables and formula on one item, then paste them onto the others that need the same inputs rather than rebuilding them each time. Paste brings the formula into the box; press Save quantity to keep it. Pasting works within the same job only, because the variables point at that job’s fields and items.

See Formula fields for more worked examples.

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Calc Sheet

Calculate quantity using the Calc Sheet. The dimension book: a grid of rows that multiply out and total.

Button	Does
Add line	New row, at the bottom
⋯ › Copy this sheet / Paste	Moves a whole sheet to another item — paste adds the copied lines below any already there
⋯ › Delete all lines…	Clears the sheet, after asking
⋮⋮ handle at the start of a row	Drag it to move the row up or down
+ / −	Adds the row, or deducts it
Copy icon at the end of a row	A copy of the row, straight under it — handy for rooms that repeat
× at the end of a row	Deletes the row

It works like a spreadsheet: the Result updates as you type, Enter moves down a row (and adds one when you are on the last), Alt+↑ / Alt+↓ moves the row you are typing in, and any box takes a sum such as =2.4+1.2. Lines save as you go, the same as before — you do not lose them by closing the window.

How a row calculates

Each row is:

Times  ×  Length  ×  Width  ×  Height  ×  Factor  ×  (1 + Wastage)

Then the rows are added together.

Any box left empty counts as 1 — Times included. That is the rule that makes one grid work for lengths, areas and volumes alike: fill in only the dimensions that apply and leave the rest blank. (An empty Times box used to save as 0 and quietly drop the whole line; it now counts as 1 like the others.)

You want	Fill in
A length	Length
An area	Length and Width
A volume	Length, Width and Height
A count	Times only

Deductions

A row switched to − is subtracted rather than added — its result goes negative, and the row is shaded so it stands out.

That is how you take out door openings, window reveals, a void in a slab. The deduction stays visible as its own line, which is the point: someone checking the bill can see the allowance was made.

Per-row wastage and rounding

Rows can also carry their own wastage and rounding, applied to that row before the rows are summed. The window does not show those two settings, but a row’s Result already includes them, so the total is always right.

Worked example

Skirting to four rooms, from a room schedule:

Description	Times	Length	Width	Deduct	Result
Living perimeter	2	9.60	—		19.20
Bed 1 perimeter	2	6.80	—		13.60
Bed 2 perimeter	2	6.40	—		12.80
Hall	2	6.80	—		13.60
Door openings	7	0.87	—	●	−6.09
					53.11 m

Width and Height are blank, so they count as 1 and the sheet returns a length.

The door deduction is the reason to use a calc sheet at all. It is on the screen, it is explicit, and anyone checking the bill can see it was allowed for.

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Manual

Manual is just a number — though the box also takes a sum starting with =. The bar along the bottom is the one worth reading: it names the other items that move when this quantity does.

Type the number into Quantity. A sum works too: start it with =, as in =12.5*2.7, and the answer shows underneath.

Right for genuine one-offs — a call-out fee, a lump sum, a figure you were given over the phone. Wrong for anything measurable, because nothing will ever update it.

Flag anything you type

Typed quantities are the ones that go stale when a drawing is re-issued, and nothing marks them. If you have to type a number for something that really should be measured, put a Flag on the item so you can find it again before you submit.

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What happens to the number afterwards

Whichever method produced the quantity, two things are applied on top, in this order.

1. Wastage

Quantity × (1 + Wastage / 100)

Set under Adjust, below the methods. Measure 100 m² with 10% wastage and the item carries 110 m². Leave the box blank for no wastage. (A blank box used to be saved as 1%.)

Keep wastage here rather than building it into the measurement. The measured figure stays an honest record of what is on the drawing, and the allowance stays visible and adjustable across a whole trade.

2. Output — rounding

The Rounding dropdown under Adjust decides how the result is presented. Eight options:

Output	What it does	Result for 18.64
Exact	Leaves it alone	18.64
Round Up	Up to the next whole number	19
Round Up to 1 Decimal	Up to the next tenth	18.7
Round Up to 2 Decimals	Up to the next hundredth	18.64
Round Down	Down to the whole number	18
Into Size	Up to the next whole multiple of the size	see below
By Size	Divides by the size	see below
By Size Rounded Up	Divides by the size, rounds up	see below

Wastage is applied before rounding, not after. So 100 m² with 10% wastage and Round Up gives 110, not 111.

The two decimal options round up, never to nearest: 18.641 becomes 18.65, not 18.64. A figure that is already at or under that many decimals is left alone, which is why 18.64 above is unchanged by Round Up to 2 Decimals. Use them for materials measured to a part-unit but ordered in sensible increments — concrete to the tenth of a cubic metre, for instance — where Round Up to a whole unit would overstate the order and Exact carries more decimals than anyone orders in.

The three “size” options

These convert a measured quantity into how many you have to buy, using the Item size under Adjust: Product’s takes the selected product’s size, Type one lets you enter it. The size box is only used by these three options, and is dimmed otherwise.

Say you have measured 47.5 m of timber and it comes in 4.8 m lengths:

Output	Maths	Gives	Means
By Size	47.5 ÷ 4.8	9.90	Lengths needed, unrounded
By Size Rounded Up	⌈47.5 ÷ 4.8⌉	10	Lengths to order
Into Size	⌈47.5 ÷ 4.8⌉ × 4.8	48.0	Metres you will actually buy

By Size Rounded Up is the one to use when you order in whole units — lengths, sheets, rolls, boxes. The item is priced per unit and the quantity is the number of units.

Into Size keeps the quantity in the measured unit but rounds it up to what you will actually receive. Use it when the item is priced per metre or per square metre but supplied in fixed sizes.

A size option needs a size

Saving one of these three options with a size of zero is refused, and says why. If the product you picked has no size, switch to Type one and enter it.

Saving this screen updates dependent formulas

Every method on this screen produces a quantity, and so do wastage, size and rounding. Any of them can move a formula elsewhere in the estimate that reads this item.

So when you press Save quantity, the BOQ recalculates those formulas for you a moment later, the same as it does after an inline quantity edit. There is nothing extra to click. See Keeping formula results current.

If you save the Formula tab with a formula the system cannot read, it says so on the screen and stores the item’s quantity as zero. Closing the screen does not make that go away: a Formula needs attention warning stays on the BOQ toolbar, and clicking it brings you straight back here to fix it.

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Choosing a method

Work down and take the first that applies:

1. Can it be measured off a drawing? → Take-off field. It follows every revision.
2. Is it the same as another item’s quantity? → Another item.
3. Does it derive from other quantities? → Formula.
4. Do you have dimensions but no drawing to measure? → Calc Sheet, so the working is recorded.
5. Otherwise → Manual, and flag it.

When a quantity looks wrong

It is zero and you did not expect it. If the method is Another item, check the source item is switched on — a switched-off source gives zero with no warning.

A size option is doing nothing. The size is empty or zero, so it falls back to 1. Check whether the item is set to use the item size or the product size, and that the one it is using has a value.

The number is bigger than the measurement. Wastage is applied before rounding — check the wastage percentage before assuming the rounding is wrong.

It did not change when you measured. The item is probably not on the Take-off field method, or is pointed at a different field. Reopen Calculate Quantity and check which method carries the In use tag.

It is higher (or lower) than the item it follows. Check whether it takes that item with or without its wastage.

A yellow “units don’t match” warning. The field or item this one follows is measured in a different unit, and nothing converts it. The classic case: concrete in m³ following a slab area in m² gives 180 m³ instead of 18 — ten times the price, and it still looks plausible in a total. Use a Formula that applies the depth (such as {A} × 0.1), or, to count items such as sheets, a “by size” rounding with the size one item covers. The warning goes away once something converts the number.

A formula gives a plausible but wrong answer. Read the Result box and check it against a rough mental figure. A misplaced decimal survives every other check.

You cannot change anything. The window says why at the top: the job is closed, the cost code is Completed, or your permissions do not include editing the BOQ.