Best Free Calculators for Australian Contractors 2026

If you're an Australian tradie — builder, paver, landscaper, electrician, plumber — there's one mistake that costs you more money than any other:

Under-quoting.

You forget to include overhead. You underestimate how many hours the job will take. You forget GST. You don't add a profit margin. And at the end of the job, you realise you barely broke even — or worse, lost money.

This is the #1 reason tradies go out of business. Not lack of work. Not bad craftsmanship. Bad pricing.

Why Most Tradies Under-Quote

It's not because you don't know your costs. It's because quoting is a mental calculation done in 30 seconds between jobs. You estimate materials, ballpark the labour, and throw on "a bit extra." That's not a pricing strategy — it's a gamble.

Here's what actually gets forgotten:

• Overhead: Insurance ($200-500/mo), vehicle costs, tools, mobile phone, office/admin — typically 15-25% of every job
• Travel: Driving to site, picking up materials, tip runs — this is billable time
• Disposal fees: Skip bins, tip fees, waste removal
• GST: 10% that the ATO takes — if you haven't included it in your price, that's coming out of your profit
• Profit margin: 20% minimum for a healthy business. Anything less and one bad job wipes out two good ones

How Much Are You Actually Making?

Let's look at a real example. A paving job in Melbourne's south-east:

You quoted $4,600. The real cost (with overhead, margin, and GST) is $7,030. You left $2,430 on the table. On a single job. And if you quoted $4,600 and ACTUALLY cost $5,590 to deliver... you just did a job for a loss.

The Solution: Tradie Quote & Job Costing Calculator

We built a Google Sheets / Excel template that does the math for you. Every time. Here's what's inside:

• 📄 Quote Calculator Sheet — enter materials (name, qty, cost), labour (hours, rate), set overhead % and profit margin. It calculates everything including GST.
• 📊 Job Profit Tracker — track what you quoted vs what it actually cost. See profit and margin per job. Know which jobs are actually making money.
• 📖 Quick Reference — step-by-step instructions and real pricing benchmarks.

It works in Google Sheets (free) and Microsoft Excel. AUD pricing. GST auto-calculated. Instant download.

How to Use It (30 seconds)

1. Download the ZIP file after purchase
2. Extract the Excel file
3. Open in Google Sheets (File → Import) or Excel
4. Fill in your job details in the gold-highlighted input cells
5. Read your FINAL QUOTE PRICE at the bottom — it includes everything
6. Copy that number to your invoice or quote template

What Tradies Are Saying

"I was quoting by gut feel for 8 years. This showed me I was leaving 20% on every job."
— Ben S., Builder, Melbourne

"First job I used it on, I realised my quote was $1,800 too low. Saved my bacon."
— Tim N., Paving Contractor, Cranbourne

Who Needs This?

• ✅ Builders and carpenters
• ✅ Pavers and landscapers
• ✅ Electricians and plumbers
• ✅ Painters and tilers
• ✅ Any tradie who sends quotes

If you quote jobs, this saves you money. Every single time.

Frequently Asked Questions

Does it work in Google Sheets?
Yes. Upload the Excel file to Google Drive and open with Google Sheets — all formulas work perfectly.

Is GST included?
Yes. The calculator automatically adds 10% GST to the final quote price.

Can I customise the overhead percentage?
Yes. The default is 15% (industry standard for tradies). Change it to whatever your actual overhead is.

What if I don't like it?
Gumroad offers refunds within 30 days. But we think you'll love it.

Is this Australian-specific?
Yes. AUD pricing, GST auto-calculated, and the job tracker works with Australian business requirements.