I owned a two condos joined into a one personal residence. Ten years later they were split and sold as two units, so two forms 1099-S. How to report for gain exclusion?

[wiyfb]

The realtor first listed the units as a single (5-bedroom) unit, but it would not sell. The total gain from the two units was under $250k.  Should I add up the proceed numbers from the Forms 1099-S and report it as a single number? Should I attach a statement explaining that a single residence was sold in two transactions?

[Hal_Al]

Yes combine the two 1099-Ss and enter it as one sale. You could  attach a statement, they are usually ignored and lost and you won't be able to e-file. Just keep good records, in case of an IRS inquiry.

Although you situation is certainly unique; a similar and more frequent case is where the homeowner splits the lot into two parcels and sells them separately. Both parcels count as sale of the principal residence, even if sold at different times.