Tenants paid a record £51.6 billion last year in private sector rent - more than twice the total bill in 2007, according to estimates.
Lettings network Countrywide, which made the projections, said the increase has been driven both by rising rents and more people renting.
Tenants paid around £49.7 billion in 2016, according to the calculations.
A decade earlier, in 2007, the total rent was put at £22.6 billion.
Countrywide's analysis suggests that for the past 11 years the millennial generation born between 1977 and 1995 have been paying the majority of total rent in Britain.
It said that in 2017 millennials paid 59% of the total rent, or just over £30 billion.
This is down from a peak of 64% of rent being paid by millennials in 2015.
As more millennials buy their own home, they will account for a shrinking proportion of the total rent paid, the report said.
Older renters still make up a significant proportion of tenants, with baby boomers born between 1946 and 1964 paying £5.5 billion or around 10% of rent in 2017. Baby boomers tend to rent larger homes and pay higher rents each month than the younger generations, Countrywide said.
Johnny Morris, research director at Countrywide, said: "The rental market grew in 2017. More people joined the rented sector and average rents increased, meaning 2017 saw the highest total rent bill so far."