Toyota 2014 Sienna Manual page 364

2-5. Driving information
Seating configuration variation
If removing the second seats, it is possible to load extra cargo equal
to the weight of the removed seats.
(Cargo capacity) = (Total load capacity) - (Total weight of occupants)
+ (Weight of the removed second seats)
Second seats weight:
7-passenger models
Tip-up seat, fabric: 45 lb. (21 kg)
Tip-up seat, leather: 47 lb. (22 kg)
Ottoman seat: 83 lb. (37 kg)
8-passenger models
Right side, fabric: 45 lb. (21 kg)
Right side, leather: 47 lb. (22 kg)
Left side, fabric: 80 lb. (36 kg)
Left side, leather: 83 lb. (37 kg)
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SIENNA_OM_OM45483U_(U)
Cargo capacity
Weight of the removed second
seat