Snowflake warehouse right-sizing matches warehouse capacity to the workload's runtime, concurrency, memory, and scan requirements.
Every warehouse size doubles the credit rate of the size below it. An XS uses 1 credit per hour, S uses 2, M uses 4, and the sequence reaches 128 at 4XL. A larger warehouse costs more per second, but it can finish some queries sooner.
The useful comparison is elapsed time and credits together. If a query runs twice as fast on a warehouse that costs twice as much, credit consumption is unchanged. If runtime does not improve, the larger size adds cost without a performance benefit.
Query profiles show execution time, bytes scanned, and bytes spilled to local or remote storage. Spilling can indicate that a workload needs more memory, but resizing is not the only response. Pruning scans, changing the query, or changing the table layout can address the cause.
Test representative queries at adjacent sizes and record credits, runtime, queue time, and spill volume. Choose the smallest size that meets the workload's latency and concurrency requirements.
Snowflake describes warehouse sizing and credit usage.