A novel method which can be regarded as the noise-counterpart of the celebrated Elmore's delay formula-both being based on the first two moments of the network's transfer function-efficiently and accurately predicts maximum noise between two capacitively coupled RC networks, without simulation. The method applies to general topologies (with significant simplification for coupled trees), accurately models how coupling varies with driver transition time, and quantifies the uncertainty in the calculated noise values. Efficient enough for large circuits, the new method can serve as a key ingredient in CAD methodologies to ensure that a layout is noise-problem free.