Hey Ira,
A Canadian salary of CAD120,000 converts to GBP68,705.80 (according to
www.oanda.com today). This is a reasonable income for London - you won't be living in Mayfair*, but you won't have to live in Tower Hamlets* either.
Assuming you are going to be treated as a normal UK taxpayer (i.e. not as an ex-pat) there are 4 taxes you need to be aware of, as follows:
1. Income Tax
2. National Insurance Contributions (NICs)
3. Council Tax
4. Value Added Tax (VAT)
The first two go up relative to your own salary & income & personal circumstances, the third is a local property tax, the fourth is a national sales tax.
Income Tax & National Insurance Contributions (NICS)
UK tax law allows you a tax-free allowance before income tax takes effect. For current tax year (April 6th - April 5th), and assuming you are a single person with no dependents, this is GBP6,475.
The calculation of income tax on a gross salary of GBP68,705.80 is as follows:
Gross salary 68,705.80
Less allowance 6,475
Salary subject to income tax (68,705.80 - 6,475) = 62,230.80
Income tax @ 22% of 37,400 = 8,228.00
Income tax @ 40% of 24,830.80 = 9,932.32
Total annual deduction = 18,160.32
National Insurance Contributions (NICs) are in fact just another income tax, albeit for historical reasons called something else and calculated on a different basis, as follows:
Gross salary 68,705.80
Less allowance 6,475
Salary subject to NICS (68,705.80 - 6,475) = 62,230.80
Weekly pay for NICS purposes (62,230.80 / 52) = 1,196.75
NICable weekly pay (1,196.75 - 95.00) = 1,101.75
Weekly NICs @ 11% of 749.00 = 82.39
Weekly NICs @ 1% of 352.75 = 3.53
Total annual deduction ((82.39 + 3.53) x 52) = 4,467.71
The combined total deduction from your salary would therefore be 22,628.03, leaving you 46,077.77 per annum = 3,839.81 per month.
For more details, see
HM Revenue & Customs: Rates and Allowances - Income Tax and
HM Revenue & Customs: Rates and Allowances - National Insurance Contributions
Council Tax
This is a property tax payable by the owner and based on a nominal valuation of the property on April 1, 1991. The impact on a renter (Brit: "tenant") is that the landlord usually passes the tax on so if there are 3 of you sharing the house, you will be paying 1/3 of the total each.
In London, the amount of the tax in each band is set by the local authority so I can't work out exactly how much you'll pay, but it will be in the region of GBP1,800 per annum = £150 per month for the property overall.
Value Added Tax (VAT)
The VAT rate is currently 15%, but goes up to 17.5% in the New Year. As a consumer everything you buy already includes VAT in the sticker price, however in certain cases, if you buy something to export, you can somtimes reclaim the tax.
Rents
Be aware that the convention in the UK is to quote rents as either "pw" (weekly) or "pcm" (per calendar month). To convert between them, multiply pw by 52/12 (4.3333 for the digital age...) to get pcm. So GBP300 pw is GBP1,300pcm. You might get away with paying the landlord as little as 1 month's deposit, but it could be as much as 3 months. You get this money back when you leave (no interest though), less reasonable deductions for wear and tear on the property. I believe the law has been tightened up in recent years, but it will still pay to find a reputable landlord who won't rip you off on departure.
Don't forget to budget for your share of the Council Tax, plus utilities (electicity, gas, water) , telephone and perhaps cable and broadband, none of which are likely to be included in the rental price quoted.
Transport
Check out the official Transport for London website to get prices on period passes for travel:
Adult Travelcard | Transport for London
but I guess you'll be paying about GBP100.00 per month.
If you have any further questions, let me know !
N
* Mayfair: richest neighborhood in the City; Tower Hamlets: poorest (by a mile).