"House price gains are primarily driven by two factors - the length of time people have owned their home and the point at which they bought in the housing cycle."
The figures show that a record 92% of sellers sold their property in 2021 for more than they bought it, having owned it for an average of 8.8 years.
Hamptons estimates that sellers across England and Wales made a total gross gain of £128bn from property sales in 2021.
While the average gross gain made by someone selling a detached house rose to £151,840, flat seller gains fell to £54,690 in 2021. One in five (19%) flat sellers in 2021 made a loss on their property compared to 4% of detached house sellers.
London sellers continued to make the biggest gains, but weaker price growth meant that 2021 marked the first time since Hamptons' records began in 2015 that London sellers made a gross gain less than £200,000.
People’s reassessment of their homes since Covid-19 began has caused sellers to move sooner. 64% of sellers in 2021 sold their home within 10 years, compared to 59% of sellers in 2019.
Aneisha Beveridge, head of research at Hamptons, said: “Soaring house price growth over the last 18 months has driven up the amount of money homeowners have made. But while owners of larger properties have benefitted from buyers looking for more space, flat owners have seen weaker returns.
“House price gains are primarily driven by two factors - the length of time people have owned their home and the point at which they bought in the housing cycle. Typically, homeowners who have owned their properties for longer have seen more price growth and therefore made bigger profits. Although, most of these profits are never seen by sellers as they are reinvested back into the housing market when they make their next purchase.
“House price gains last year may have been close to their peak. 2021’s average seller bought in 2012, since when house prices across England and Wales have risen by 55%. However, 2022-2024 sellers are likely to have bought more recently, during a period of weaker price growth. We’ve already seen this in London, where seller gains have been falling since 2016.”