This represents a rise from just above £170,000 in August 2019 to approximately £190,000 in August 2021.
Trussle said a number of factors have likely led to homeowners seeking larger mortgages, such as declining interest rates offering better deals.
In addition, while there has been little change in household income during coronavirus, households decreased their spending on non-essential items.
As a result, savings as a proportion of household disposable income increased from January to March 2021.
Trussle’s data also found that mortgage borrowing amounts continued to increase during 2020 and into the new year.
In May 2021, the average mortgage loan size for Trussle customers reached a 24-month high of £210,057.
Miles Robinson, Head of Mortgages at online mortgage broker Trussle, said: “People have been incredibly sensible during the pandemic and as a result households’ savings have grown considerably.
“This, coupled with incentives like the stamp duty holiday and lower interest rates, has meant that home buyers have had much more flexible budgets when it comes to finding their perfect home.
“However, we shouldn’t presume that buyer appetite for bigger mortgages is here to stay.
“As the UK continues on its path to reopening, spending on non-essential items will understandably begin to increase again, as such, homebuyers’ savings will likely begin to shift back towards pre-pandemic levels and mortgages will shrink accordingly.”