A distinction is made between mixing ratios in percent by weight or volume. On the construction site, measuring in containers (volume) is easier than if the components have to be weighed.

Hydraulic lime
(1 bag of 50 kg = 55 liters)
(1 liter = approx. 0.78 kg)
Cement
1 bag of 50 kg = 43 liters
Tuff
1.25 kg = 1 liter
Sand
1 liter = approx. 1.2 - 1.5 kg

Very flat stones: 250 liters of mortar / m3 of finished masonry
Less flat stones: 280 liters of mortar / m3 of finished masonry
Irregular stones: 300 -350 liters mortar / m3 finished masonry
Mortar requirement for pointing: 15 liters of mortar /m2 finished surface

Recalculation Lenzburg masonry: approx. 300 liters mortar / m3 masonry

Recalculation Lenzburg Pointing: approx. 15 l mortar / m2 surface 

Calculation of lime and sand requirements. The values below each give one m3 of finished mortar:
Mortar with hydraulic lime