Where do the figures in the calculator come from?

From you. The calculator contains no rates or prices. Enter the figures from contractors' and suppliers' quotations for your own drawings and specification, either as a rate for each sq ft of carpet area or as a lump sum, and it adds them up and divides them out.

Should I enter rates or lump sums?

Whichever your quotation gives. Work spread across the whole floor, such as flooring, ceilings, lighting and HVAC, is often quoted as a rate for each sq ft of carpet area. Furniture, IT, AV and doors are more often quoted as a lump sum or a list of items. Each line can be set either way.

How much contingency should a fit-out budget carry?

The calculator does not set one. Contingency covers what is not yet known: site conditions, design changes, items not yet chosen. It is usually larger early in a project, when drawings are incomplete, and smaller once the scope is fixed and quoted. Agree the figure with your project manager or quantity surveyor.

What if my quotations already include GST?

Set the assumption to say your figures already include GST. The calculator then takes GST out of each line at the rate you enter, adds the contingency and fees on the before-GST figure, and puts GST back on the whole budget, so every line is treated the same way.

Why does the cost for each seat matter?

Because two offices of the same area can seat very different numbers of people. The cost for each seat shows what the fit-out costs for each person it accommodates, which makes options with different layouts or densities easier to compare than the cost for each sq ft alone.

Office Fit-Out Budget Calculator by Line Item

What it calculates

The calculator builds an office fit-out budget from figures you enter and shows:

the before-GST amount of each line item, and its share of the budget;
the line-item subtotal;
the contingency and the design and project management fees you choose;
GST on the whole budget, and the budget with GST;
the cost for each sq ft of carpet area, if you enter the area;
the cost for each seat, if you enter the number of seats.

It contains no rates or prices, and Hagerstone supplies none. Every amount is yours, taken from your own quotations. The calculator stores nothing and starts blank.

Inputs

Carpet area: the usable floor area being fitted out, in sq ft. Needed for any line entered as a rate.
Seats: optional, the number of workstations and other seats the layout provides.
Line items: civil works and flooring, false ceiling, partitions and doors, furniture and workstations, electrical and lighting, HVAC, fire and safety, IT and AV, and other. For each, choose whether your figure is a rate for each sq ft of carpet or a lump sum, and type it in. Leave a line blank if it is not in your scope.

In the assumptions panel:

Contingency: a percentage of the line-item subtotal, or blank for none.
Design and project management fees: a percentage of the line-item subtotal, as stated in your consultant's proposal, or blank for none.
Your figures are: before GST, or already including GST.
GST rate: starts at 18%, the same as the quotation comparison tool.

Where to get the figures

Ask two or three contractors to price the same drawings and specification, then put their quotations on one basis with the fit-out quotation comparison before you take figures from them. If one line is not yet designed, ask for a budget figure for that line from a supplier and treat it as provisional. Whether the landlord's warm-shell work already covers the ceiling, lighting and HVAC changes how many lines you need; the Cat A and Cat B fit-out entry explains the split.

Method

Each line before GST = your rate × carpet area, or your lump sum. If your figures include GST, each line is divided by (1 + GST rate).
Line-item subtotal = the sum of the lines.
Contingency = subtotal × contingency %.
Fees = subtotal × fee %.
Budget before GST = subtotal + contingency + fees.
Budget with GST = budget before GST × (1 + GST rate).
Cost for each sq ft of carpet = budget with GST ÷ carpet area.
Cost for each seat = budget with GST ÷ seats.
Share of the budget = each line (or contingency, or fees) ÷ budget before GST.

Assumptions

Assumption	Default	Notes
Line items	Blank	Your own figures, from quotations
Each line entered as	Rate for each sq ft of carpet	Switch any line to a lump sum
Contingency	Blank (none)	Your allowance; agree it with your project manager
Design and PM fees	Blank (none)	As stated in your consultant's proposal
Your figures are	Before GST	Switch if your quotations include GST
GST rate	18%	Confirm the rate for your contract with your accountant

Contingency and fees are worked out on the line-item subtotal, not on each other. If your consultant's fee is a fixed amount rather than a percentage, enter it on the Other line as a lump sum and leave the fee percentage blank.

Limitations

It is only as good as the figures you enter. A line priced from a thin specification, or a quotation with large exclusions, will understate the budget.
One GST rate applies to everything. If different parts of your budget attract different rates, work them out separately with your accountant.
It leaves out costs outside the fit-out. Rent during the works, the security deposit, moving, landlord approval fees and statutory fees are not included unless you add them on the Other line. The office occupancy cost calculator spreads one-time costs over the lease alongside the running costs.
It does not check the scope. Nothing in it tells you whether a line is missing or doubled up between two quotations.
It does not judge whether a figure is reasonable. It adds and divides; it does not compare your figures with any benchmark.

Worked example

Suppose an office of 1,000 sq ft carpet area with 20 seats. The figures below are invented for the example and are not market prices.

Civil works and flooring: 10 units for each sq ft.
False ceiling: 5 units for each sq ft.
Partitions and doors: a lump sum of 7,500 units.
Furniture and workstations: a lump sum of 20,000 units.
Electrical and lighting: 8 units for each sq ft.
HVAC: 12 units for each sq ft.
Fire and safety: a lump sum of 2,500 units.
IT and AV: a lump sum of 5,000 units.
Contingency 5%, fees 5%, figures before GST, GST at 18%.

Line	Calculation	Before GST	Share
Civil works and flooring	10 × 1,000	10,000	13%
False ceiling	5 × 1,000	5,000	6.5%
Partitions and doors	Lump sum	7,500	9.7%
Furniture and workstations	Lump sum	20,000	26%
Electrical and lighting	8 × 1,000	8,000	10.4%
HVAC	12 × 1,000	12,000	15.6%
Fire and safety	Lump sum	2,500	3.2%
IT and AV	Lump sum	5,000	6.5%
Line-item subtotal		70,000
Contingency	70,000 × 5%	3,500	4.5%
Fees	70,000 × 5%	3,500	4.5%
Budget before GST		77,000
GST	77,000 × 18%	13,860
Budget with GST		90,860

The budget with GST is 90,860 units: 90.86 units for each sq ft of carpet area and 4,543 units for each seat. Furniture is the largest single line at about a quarter of the budget, so it is where a change of specification moves the total most.

How occupiers use it

An occupier planning a move usually needs a budget before the design is finished: to get board approval, to compare two buildings, or to decide between a turnkey contract and separate packages. The budget starts with a few lump sums and rough rates from early quotations and is refined as drawings and quotations firm up, line by line.

Kept up to date, the same breakdown becomes the cost plan the project is tracked against. The share column shows which lines matter most, which is where value engineering is worth the effort. The turnkey and item-rate contract comparison explains how the contract route changes who carries the risk on each line.

When a professional estimate must replace it

Use the calculator to organise your own figures, test what a change in one line does to the total, and compare options on cost for each seat. Replace it with a cost plan prepared by a quantity surveyor or cost consultant against measured drawings and a specification before you commit to a budget, and with tendered prices before you sign a contract. Have the GST treatment of your contracts confirmed by your chartered accountant.

Office Fit-Out Budget Calculator: Build a Budget from Your Own Figures