The cathedral’s proportions are unusual, necessitated by the desire to create a feeling of volume and balance. Its dimensions were dictated by the old Romanesque building, whose central nave was 16 metres wide. This width is quite manageable when it comes to constructing a roof frame but makes creating a balance quite a challenge where stone vaulting is used. This challenge was compounded by the requirement to build high above this narrow width: the vaults in the nave are 37 metres high. The dimensions of the nave meant that sexpartite vaulting was not appropriate and that more effective and elegant quadripartite vaults with a rectangular plan had to be used. This was an innovative solution which had been used experimentally a few years previously at Noyon. A much bigger choir was also built, to accommodate the large number of canons. A vast transept projecting a long way from the nave was constructed to house the processions of the faithful and given more solemnity by the porches built on the ends of the transept arms.
- Length: 130.2 m
- Width of the nave: 16.4 m
- Transept: 13.99 m wide and 64 m long
- Height of the vaults: 37 m
- Side aisles: 8.2 m each
- Romanesque bell tower (south side): 106 m
- Jehan de Beauce bell tower (north side): 115 m