If you have been trading for a year, you will have a smaller number of mortgage lenders to choose between - the majority of mainstream lenders will need to see three years worth of trading. Hence this being a niche product.

The Revolution Guide to securing a mortgage after one year's trade provides more information.

The income calculations are the most significant difference between a standard mortgage and one for a self-employed applicant.

If you fall into one of the below circumstances, the income multiples that lenders use to decide the maximum they can lend are likely to be the same as for a full time employed person:

• Self-employed for three years or more
• Earn an established income from a sole trader business
• Receive a limited company salary and dividends

If you have been trading for under three years or have a complex income structure, including bonuses and commissions, the calculation can vary depending on the lender.

Some mortgage providers might only consider part of your income declarable for the income calculations, and this can have a massive impact on the amount you can borrow.

Some mortgage providers might only consider part of your income declarable for the income calculations, which can have a massive impact on the amount you can borrow.

As we've discovered, getting a mortgage when self-employed requires an income assessment. Lenders will usually work out an average annual income and make an offer based on that.

In the below table, we've shown indicative examples of what you might be able to borrow based on your earnings history:

If you approached three different lenders, all of whom offer a maximum mortgage of four times your annual salary, the way they calculate your average income will mean each lender might offer a very different value.

These examples assume that you have no other outgoings, and your net profit or salary income is your total earnings.

This variance demonstrates why it is crucial to work with an experienced broker who knows how much you'd like to borrow and how the lending calculations work with each lender.

Suppose you're looking to buy a house with somebody else. In that case, you'll generally be able to borrow more on a mortgage because the lender will consider two incomes in their maximum lending calculations.

However, things can be a little trickier if you need a joint mortgage with one self-employed person and the other in PAYE employment.

The process works pretty much the same as for any other self-employed mortgage. The lender will usually look at:

• An average of what you earn per year.
• How much the other person makes through their salary.
• Other debts and credit facilities.
• Your ages and any property risk factors.

If you've been trading for one year or want to base your mortgage application on the profits from last year (perhaps you've seen a massive uptick in trade!), it's important to use an experienced self-employment mortgage broker to navigate the borrowing market.

While some lenders are very strict and won't lend to any self-employed mortgage applicants with under three years of filed accounts, others will help.

The key is to apply to a mortgage lender with specific experience lending to self-employed applicants willing to base their lending offer on your income from the most recent trading period.

You can apply for a mortgage with up to four people, usually as a maximum. The lender will need to run through the same income assessment and affordability calculations for each applicant.