Is there a MPG rule of thumb when towing?

I have a Swift Conqueror towing with a Toyota Land Cruiser LC4 when towing to Cornwall a few weeks ago got 18.9 average towing at 60 mph on the motorway that was into a headwind. On the homeward journey got 21.3 no wind. It is what it is. Anybody who moans about fuel economy should give up towing a caravan.

Brian. 

Over many years of towing with a variety of cars I have found that as a very rough rule of thumb my average towing consumption is very approximately 60% of the average solo driving.

There are so many variables that a precise figure can never be assumed, even doing the same journey. 

If your worried about MPG when towing, then the asnwer is don't tow. I don't care what I get, I just drive to destination in a calm manner and arrive relaxed and fill up when required. 

As others have indicated, it depends a lot on the car. Most of the towers that I had until a few years ago used about 50% more petrol or diesel, as the case may be, but then they were often borderline regarding their towing ability. Then I changed to a hybrid which used almost double the amount of fuel towing than when solo in town traffic. This was because both the electric motors AND the IC engine were working pretty much full time when towing but in town it was on electric only quite a lot. My current relatively powerful diesel uses only about 20% more, so it's difficult to quote a rule of thumb.

I don't believe the OP was worried about fuel consumption when towing ... just curious.

The user and all related content has been Deleted User

" I don't believe the OP was worried about fuel consumption when towing ... just curious."

I also don't think he was asking what you got from towing. 

my mpg figures were given for comparison ... 😘

Maybe you want to say the same to all the others who offered their mpg figures on this thread! 

Unless you are into believing fairy tales then the rule of thumb for towing fuel consumptions is going to be, it will be “sick”.
The more so with the modern vehicles where taxation, rather than other performance criteria, drives them to be optimised to achieve the lowest possible carbon figure whilst being tested to the specific EU test routine. Then towing we approach near doubling their mass and wrecking the aerodynamic drag.
Where, the vehicle is heavy relative to the caravan, where is frontal area is bulky and profiled similar to the caravan's and where it is furnished with an engine and gear set chosen for load lugging, then reasonably the towing impact on its fuel consumption will be felt less as a percentage than with using a sleek minimalist drag profile ultra light weight vehicle. Tow with a Transit van and I expect you will not notice as big a difference as to say a Golf.

For the last thirteen years we have towed a 1900 kg van with a Disco 3 and now a 4, 2.7 litres and 3 litres respectively and the latter giving about 1 mpg better overall. The actual value reflecting the terrain, very much the nature of the roads be that rolling auto route, or umpteen roundabouts, and head or tail wind.
On a good free running long journey I can see 35 MPG solo, and touching 24 towing, overall thought on a multicplicty of journeys that changes to an average of 28 and 21.6.

Ford SMax.  Towing cuts MPG by 50%.  Goes from 40-45 to 20-25