Depends on how many bytes in table, and how long a row is.
A SQL page is 8K, with 8060 total bytes available for data. Each row resides on a single page (excluding special column types).
So if every row takes, say, 4100 bytes, each would take a whole page, with the rest of that page unuseable except to expand the existing row.
SQL DBA,SQL Server MVP('07, '08, '09)
Prosecutor James Blackburn, in closing argument in the "Fatal Vision" murders trial: "If in the future, you should cry a tear, cry one for them [the murder victims]. If in the future, you should say a prayer, say one for them. And if in the future, you should light a candle, light one for them."