Towing Weights Calculator

This calculator will help you understand and calculate the various weights involved when you tow; for example how much payload you have left, whether a towcar can tow a trailer, how close you are to limits such as GCM.

The calculator assumes you are familiar with terms like GVM, GCM and TBM. If you’re not, then please read this first, then come back here.

If you are familiar with towing weights, then here’s some explanatory notes about the calculator.

Calculator results are for guidance only – final checks should be made using all the data and limitations specific to your towcar and trailer which this calculator may not cater for.

Enter your trailer and towcar details below
Your reference: Whatever you want to name this calculation, e.g. "Ford Ranger and DreamVan". Not used in calculations. Only a-Z, 0-9 and - allowed.
Trailer
Actual trailer weight		Measure this; tailer ready to tow, including TBM; this should be equal to or less than the trailer's ATM.
Trailer ATM		Maxium weight of trailer; refer to trailer placard. The ATM should be equal to or more than the trailer's actual weight.
Towball mass (TBM)		Measure this; as ready to tow. If you can't measure it, use 10% of trailer weight.
Towcar
Actual towcar weight		Measure this; towcar ready to tow but unhitched; accessories, luggage, people, fuel etc. This should be less than the towcar's GVM.
Towball mass (TBM) limit		The maximum TBM. Look on towcar's placard, towbar, and tow tongue; use the lowest figure of the three.
Max tow capacity		Refer to vehicle specs. Maximum braked towing capacity.
GVM		Gross Vehicle Mass. Refer to your vehicle's weight placard.
GCM		Gross Combination Mass. Refer to vehicle's specs.
Email	Leave blank unless you want results emailed to you. Email not stored or used for any other purpose.
Calculate

 

Results
Trailer and towcar details
Total trailer weight	2500	The weight of your trailer, as ready to tow, including TBM.
Towball mass (TBM)	250	Usually around 10% of trailer weight.
Towcar weight	2600	Weight of your towcar, as ready to tow.
Max tow capacity	3000	Maximum braked tow capacity of your towcar.
GVM	3100	Gross Vehicle Mass of your towcar.
GCM	6000	Gross Combination Mass of your towcar.
Towing weight calculations - guidance only
Combined weight:	5100	Towcar & trailer combined, ready to tow. This must not be greater than the GCM.
Percentage of trailer weight to towcar weight:	96 %	The lighter the trailer relative to the towcar the better, ideally this would be less than 100%.
Difference to ATM:	500	You are within the ATM of 3000 by 500.
TBM as a percentage of trailer weight:	10 %	Towball mass (TBM) of your trailer; weight on the towball.
Difference to max TBM:	50	How far away you are from exceeding the TBM limit. Your rear axle load will increase by about 375 and your front axle load will decrease by about 125.
Difference to GCM:	900	You are within the GCM limit of 6000 by 900.
Difference to GVM:	250	You are within the GVM of 3100 by 250.
Difference to max tow:	500	Your trailer weight of 2500 is within the max tow of 3000 by 500.
Payload left before reaching a weight limit:	250	In this configuration, your payload is limited by GVM.
The heaviest trailer this towcar can tow is:	3000	This is the heaviest trailer you can tow given the weights input above (assumes 10% TBM). Your maximum trailer weight is the towcar's maximum braked tow limit.
Version 9 - 16/10/2020

If you have questions, comments or feedback please post them on the help page, after you’ve read it and the explanations 🙂

The calculator and the information provided is free to you but cost me to produce and maintain, so please consider supporting me on Patreon and YouTube. Sponsorship welcome so long as independence is maintained.