How it works: Under the old CGT rules, only 50% of your nominal gain was taxable after 12 months. The government has removed this discount. This calculator shows how many years you need to hold the property so that inflation reduces your real gain to the same amount as the old 50% taxable gain — achieving the same tax benefit through time rather than legislation. Cost base is adjusted by CPI using compound annual growth. This is not financial or tax advice. Consult a registered tax adviser.