How we work this out: We don’t count every loan as a saving. We only count the share that replaced buying something new, in line with the method Libraries of Things use across the UK. Money saved is the new-buy price of those items, minus what members paid to borrow them. Carbon saved is the manufacturing emissions of the items that never had to be made. Where a figure is an estimate, we say so—and we’re sharpening it as we gather our own data.