The index, which includes data from Zoopla and the Land Registry, gives a breakdown of the market including a calculation of the average rental yield by postcode and by number of bedrooms.
Users are also provided with interactive graphs and charts.
The index, which is compiled by the LendInvest data science team, is accessible from the peer-to-peer platform’s website.
Christian Faes, chief executive officer of LendInvest, said: “The LendInvest buy-to-let index is consistent with our whole ethos at LendInvest - providing investors with quality information, and bringing transparency to what is often an opaque market.
"We're aiming to provide investors, on both sides of our peer-to-peer marketplace, with as much information as possible on the UK buy-to-let market.
“We are keen to ensure that both our borrowers and our lenders are making sensible and informed investment decisions.”
According to October’s LendInvest Buy-To-Let Index the average buy-to-let rental yield is currently 5.9% per annum for 1-bedroom properties compared to 4.6% for 3-bedroom homes.
Capital gains on buy-to-let properties stands at 2.5% per annum on average over the past four years.
Over the last year the highest investment gains have been in the postcode areas EC3, QC1 and QC2, which made year-on-year gains of 25%.
On the flipside the worst performing postcode was L8 in Liverpool.
Faes added: "The LendInvest buy-to-let index shows that buy-to-let property is not always a great investment.
“There are many postcodes across the country that have experienced negative capital gains.
“The LendInvest peer-to-peer platform provides investors the opportunity to obtain a very decent return, lending secured against property, but without the hassle and risks associated with direct property investment.”