Size an Amazon Neptune cluster from graph size and query rate, then price instances, cluster storage and graph I/O.
Neptune storage is estimated from element counts because a graph's footprint is dominated by adjacency lists and property values rather than by rows, and it is billed in the same shared-volume model as Aurora with a 10 GB minimum. Reads scale out across up to 15 replicas, but a graph traversal touches many pages per query, so the per-million I/O charge often outgrows instance-hours on deep multi-hop workloads. Every rate here is an editable input with a realistic us-east-1 default, so confirm current Neptune prices with AWS for your region. Traversal depth, not data volume, is what makes a graph workload expensive — modelling I/O per query is how you discover that a three-hop query pattern costs more in I/O than the whole reader fleet costs in compute.
Neptune Cluster
graph bytes = vertices × bytes per vertex + edges × bytes per edge; instances = 1 writer + ceil(QPS ÷ per-instance QPS), capped at 16; I/O millions = QPS × I/O per query × 2,628,000 ÷ 1,000,000.
graph bytes = vertices × bytes per vertex + edges × bytes per edge; instances = 1 writer + ceil(QPS ÷ per-instance QPS), capped at 16; I/O millions = QPS × I/O per query × 2,628,000 ÷ 1,000,000. Neptune storage is estimated from element counts because a graph's footprint is dominated by adjacency lists and property values rather than by rows, and it is billed in the same shared-volume model as Aurora with a 10 GB minimum. Reads scale out across up to 15 replicas, but a graph traversal touches many pages per query, so the per-million I/O charge often outgrows instance-hours on deep multi-hop workloads. Every rate here is an editable input with a realistic us-east-1 default, so confirm current Neptune prices with AWS for your region.
Traversal depth, not data volume, is what makes a graph workload expensive — modelling I/O per query is how you discover that a three-hop query pattern costs more in I/O than the whole reader fleet costs in compute.
This calculator takes 11 inputs: Vertices in the graph, Edges in the graph, Average bytes per vertex, Average bytes per edge, Peak query rate, Query capacity of one instance, Storage I/O per query, Instance price, Billed hours per month, Storage price, I/O price. The pre-filled defaults are a realistic starting point — replace them with figures from your own environment for a result you can act on.
A Neptune cluster supports one writer and up to 15 read replicas. Beyond that you need to partition the graph across clusters or move to a Neptune Analytics graph for heavy analytical traversals.