Commercial fitout software for estimating, claims and GST invoicing

Commercial fitout businesses in Australia run on a paperwork problem that is easy to underestimate. You are estimating tenancies off PDF plans, chasing subbie quotes over text, writing up variations on a notepad, and then spending your evenings trying to match Xero invoices against staged claims across three live projects. Many shopfitters pay from $199/mo for an estimating tool like Buildxact and from $37/mo for Xero, and still end up tracking retention and variations in a spreadsheet that only they understand. The result: you do not know the real margin on a fitout until it is finished, and you cannot always prove what was agreed when the head contractor queries a claim.

OneBookPlus gives you one app for your whole fitout business. Take off quantities from the plans, build a sectioned estimate from your own cost catalogue and recipes, partitions and ceilings per m², shopfront and joinery by the item, PC and provisional sums as their own lines, with GST calculated automatically. When the contract is signed, the job drops onto your program. Capture variations with client approval as scope changes, photograph each stage, and raise progress claims against the schedule of values with retention withheld, each one a GST-compliant claim the head contractor can pay online. Log every subbie and supplier cost against the job so the real margin is never a guess. No more spreadsheet retention ledgers, no more variation disputes, no more Sunday night reconciling claims.

Estimating from a cost catalogue

The thing generic job apps get wrong for shopfitters is the estimate. A fitout is dozens of assemblies priced different ways: framing and plasterboard per m², suspended ceilings per m², shopfront glazing and joinery by the item, floor finishes per m², plus electrical and mechanical you sub out. OneBookPlus (with the Builder Suite add-on at $99/mo) keeps all those rates in one cost catalogue and lets you build reusable recipes that price a partition or a ceiling in one click, grounded in your real supplier and subcontractor rates with wastage built in. AI can draft the whole sectioned estimate from a description or the plans, and a built-in reviewer flags anything missing before it goes out. You review every line; the AI does the first draft. If you are weighing tools rather than shopping for one, our guide to estimating software for Australian trades covers what a takeoff and pricing engine has to get right.

Tendering to a head contractor

Most fitout work arrives as a tender package rather than a phone call, and the package sets the terms of the argument you will be having six months later. The drawings and the specification tell you what is in scope, the preliminaries tell you what the site will cost you in access, hoarding, waste and inductions, and the exclusions you write are the only protection you have when something outside the package turns up on site. Price the preliminaries as visible lines rather than folding them into a rate, because a head contractor comparing three tenders on a single number will always pick the one that hid the most. Where the design is not settled, carry the item as a provisional sum and say so, instead of guessing and wearing it. In OneBookPlus the estimate keeps every section, allowance and exclusion as its own line, the accepted version becomes the contract value on the job, and every later variation moves that value rather than living in an email chain. When the same head contractor comes back with the next tenancy, their whole history sits on one contact: what you fitted, what it cost you and what was claimed.

Progress claims, retention and cash flow

Staged commercial fitouts rarely pay in one invoice at the end. They run on progress claims against a schedule of values, deposit, demolition, framing, services rough-in, linings, joinery, fit-off, practical completion, with a retention percentage held back until defects are made good. Waiting until the job is done to bill it is what strangles a fitter's cash flow. OneBookPlus lets you raise each stage as its own GST claim that draws down the contract value and withholds retention, with the balance owing and the retention held always clear on the job. The progress claims feature overview walks through setting up a schedule of values. Under the state and territory Security of Payment laws, progress payments and retention are a formal part of commercial contracting, and OneBookPlus keeps the paper trail clean. This is general information about how the software works, not legal or tax advice.

Working to a tenancy handover date

A fitout is not really a construction program, it is a countdown to a trading date somebody has already advertised. The landlord has a handover, the retailer has a launch, and every trade is stacked back to back because there is no float to give away. That changes what scheduling has to do: the question is never just who is on site today, it is which stage is holding up the three behind it. Lock the program to the handover date, put each stage and the subbie who owns it on the week view, and when the mechanical contractor slips a day, drag the stage and let the reminders tell the crew and the head contractor rather than finding out at the next site meeting. Keep the site photos and the diary going as you build, because when the program is questioned at the end, dated evidence of when each stage was actually available to you is worth more than anyone's recollection. For the wider picture of running several projects at once, see our construction project management software guide.

Variations and RFQs

Fitout scope moves constantly: the client relocates a wall, upgrades the joinery, adds a data run after the walls are up. Capture each variation with a description, price and one-tap client approval before you build it, and it adds to the contract value and flows into the next claim, so the margin and the paper trail are protected. From the same job you can send requests for quote to your joiners, electricians, mechanical and flooring subbies, compare what comes back, and pull the priced items straight into your estimate, with those subcontractor costs landing against the right job. Before you commit to a rate across a roll-out of stores, the free markup and margin calculator is worth a minute.

Invoicing, GST and BAS

Every claim and invoice carries your ABN and calculates 10% GST, meeting ATO tax-invoice requirements without you doing the maths. Where your work type and contract value require a building or trade contractor licence in your state or territory, show that number on the quote and invoice too. Head-contractor payments made through the invoice link clear the claim on their own, and subbie and supplier costs land in the right accounts as you enter or import them. There is no live bank feed at the moment, so anything paid outside the link is imported from a statement. Come BAS time, your GST summary is already prepared: GST collected on claims, GST credits on purchases, and the net owing. Export it in one click, and use the free GST calculator when you want to split a figure by hand. This is general information about how the software works, not tax advice, so confirm your specifics with your accountant or the ATO.

Getting started

Sign up free, no credit card, no lock-in contract. Choose “Shopfitting & commercial fitout” as your business type and OneBookPlus pre-configures fitout service categories, typical job types (retail fitout, office fit-out, café and hospitality, shopfront, tenancy make-good) and claim templates. Import your client and head-contractor list via CSV from Buildxact, a job app, or a spreadsheet, set up your cost catalogue, recipes and progress-claim stages, and set your invoice branding and numbering. You can send your first estimate the day you sign up. Switching from an estimating tool plus Xero is designed to fit in a single evening.