A measuring vessel (1) for determining the accuracy with which a liquid fuel dispenser dispenses liquid fuel comprises a neck (4) of transparent material. A primary arcuate panel (16) having three primary graduated scales (14) corresponding to three different kinds of liquid fuels is secured to the neck (4). Primary graduations (17) of the respective primary graduated scales (14) indicate the level to which the meniscus of actual volumes of the respective liquid fuel dispensed at the temperatures corresponding to the primary graduations (17) should rise so that the energy content of the actual volumes of the respective liquid fuels dispensed is equal to the energy content of a predefined calibration volume of the corresponding liquid fuel at a predefined reference temperature typically of 15° C. A secondary arcuate panel (20) having a secondary graduated scale (22) thereon is slideable relative to the primary graduated scales (17) so that a reference graduation (23) of the secondary graduated scale (22) can be aligned with an appropriate one of the primary graduations (17) of an appropriate one of the primary graduated scales (14), in order that the amount by which the actual volume of liquid fuel dispensed exceeds or falls below the actual volume which should have been dispensed.