More than a quarter of families in England's private rented sector have moved house at least three times in the last five years, according to Shelter.
The housing charity said the figures reflect the "unstable" nature of renting, which can have damaging effects on the children living in the sector.
The findings, from a Shelter/YouGov study of more than 3,700 private renters, show that 27% of renting families in England have moved three or more times in the past five years.
This equates to more than 400,000 families moving at least three times in the past five years across England, if the survey's findings are projected across the country.
The research found that nearly half (46%) of renting parents were forced to borrow money or had fallen behind on other payments due to the costs of their last move.
Alongside the strain on their finances, parents reported that the lack of stability had a damaging effect on their children. More than one in four (26%) said that moving had a negative impact, with many reporting that it left their children feeling distressed, upset and insecure.
Parents reported their children's education being disrupted as well as them having to leave friends behind.
The charity found that 6% of privately renting families had to move their child's school with their last house move - equating to 65,000 families across England.
The charity is calling for longer-term tenancies to be introduced, to give families greater stability.
It found that more than nine in 10 (92%) families said that when they are looking for a new rented home it is important they can stay there long-term if they want to.
Campbell Robb, chief executive of Shelter, said: "Today's sky high housing costs mean private renting is no longer just a stepping stone for young adults - it's where a quarter of all families in England have to live. It's shocking therefore that it is still not fit for purpose."
The charity quoted interviews it has conducted with renters, including one who said: "Every time we moved we had to find £2,000, increasing each time, for deposits, searches, admin fees."
In another case, a renter said: "So when we were evicted my children had to move schools. And then they had to change again when we got evicted from there, again because the landlord wanted it back."
A Department for Communities and Local Government (DCLG) spokesman said: "We're determined to create a bigger, better private rented sector and are attracting billions of pounds of investment to build homes specifically for private rent, which will increase choice for tenants. We have also introduced measures to ensure tenants can be confident they will get a fair deal.
"With 86% of the public saying they want to own their own home, we want to ensure anyone has the opportunity to do so. That's why we've doubled the housing budget to support the boldest plan for housing by any government since the 1970s, with Government initiatives having already helped nearly 270,000 people to buy since 2010."