Estimate row size from column types plus per-row and page overhead.
Databases read whole pages, so rows per page determines how much input and output a scan costs. Narrow rows fit more per page and scan proportionally faster. A row slightly over half a page size wastes nearly half of every page, which is why row width has outsized effects on scan performance.
Database Row Size
Row size = column data + per-row header; rows per page = usable page bytes ÷ row size
Row size = column data + per-row header; rows per page = usable page bytes ÷ row size Databases read whole pages, so rows per page determines how much input and output a scan costs. Narrow rows fit more per page and scan proportionally faster.
A row slightly over half a page size wastes nearly half of every page, which is why row width has outsized effects on scan performance.
This calculator takes 5 inputs: Integer columns, Big integer or timestamp columns, Variable text columns, Average text length, Per-row header overhead. The pre-filled defaults are a realistic starting point — replace them with figures from your own environment for a result you can act on.