Percentage Calculator for Western Australia — WA Local Guide 2025
This calculator is optimised for Western Australia residents with local data points relevant to the WA context. Whether you're in Perth or regional Western Australia, the calculations apply Australia-wide with WA-specific notes where relevant.
Western Australia at a Glance — 2025
- Capital city: Perth
- State population: 2.9M
- Average metropolitan house price: $680,000
- Average weekly rent (Perth): $620/week
- Minimum wage: $24.10/hr (national rate, applies in WA)
- Average fuel price: 165–205c/L
Cost of Living in Western Australia
Perth has a relatively moderate costs of living among Australian capital cities. Housing is typically the largest expense, followed by transport, food and utilities. Understanding your financial position — using tools like this calculator — is important for effective budgeting in WA.
Frequently Asked Questions
How do I calculate a 20% discount?
Multiply the original price by 0.80 (the remaining 80% after the discount). $250 × 0.80 = $200 discounted price. Alternatively, find the discount amount: $250 × 0.20 = $50 off. Both methods reach the same result.
How do I calculate percentage change?
Formula: ((New Value − Old Value) ÷ Old Value) × 100. If revenue went from $80,000 to $100,000: ((100,000−80,000)÷80,000)×100 = 25% increase. If it went from $100,000 to $80,000: ((80,000−100,000)÷100,000)×100 = -20% (a 20% decline).
How do I find the original price before a discount?
Divide the discounted price by (1 − discount as decimal). For a 20% discount: divide by 0.80. If the sale price after 20% off is $200: $200 ÷ 0.80 = $250 original price. For removing 10% GST: divide by 1.10.
What percentage markup gives what profit margin?
These are different calculations. A 25% markup (profit ÷ cost = 25%) gives only a 20% margin (profit ÷ revenue = 20%). A 40% markup gives a 28.6% margin. To get a 25% margin, you need a 33.3% markup. Many Australian business owners confuse these, which leads to underpricing.