easyeasy,
係咁既:
1. 因為我係供樓+雜費唔可以超過1/5總收入, 所以要將雜費除0.2或者乘5, 舉例: 收入$60000, 可以供款 = 1/5 * ($60000 -$3000/0.2) = $9000. For checking: $60000*1/5 = $12000 = $9000 + $3000.
2. 而家銀行供樓係以P-?%黎計, P=Prime rate, 而家係5%, 一般銀行而家按揭係P-2.7%, 所以現時息率係2.3%. 不過香港減左幾年息, 個P先咁低, 好多人都預期會加息. 我睇過d報章, 呢幾年香港應該會累積加多3%, 所以我咪用P=8%囉.
3. trial and error既意思係 - 因為我剩係知我可以afford幾$供款, 但唔知可以買到幾多$既樓. 入去地產網頁, 佢地個供款計算機係你要input層樓價錢, interest rate, 供款年期, 用黎計下你每月供款大概幾多. 咁我已既知係interest rate, 供款年期, 每月供款幾多, 我咪不斷input樓價, 睇下大概幾多樓價最接近我既每月供款囉.