How we count

We read all 1,328,559 non-domestic certificates in the register’s full load of 2026-10-01, keep the newest certificate for each unit, and count a certificate as valid for ten years from lodgement.

What counts as let

A unit counts as let if any of its certificates was lodged “for letting”. That undercounts: a unit let on a certificate produced for a sale does not show, and we cannot see a let that has ended.

What we cannot see

• Exemptions. An F or G unit may be lawfully let under an exemption on the PRS Exemptions Register. We do not have that register.
• Units over 1,000 m². These are counted separately and are not on this site.
• Councils with too few units. We publish a council only if at least 30 let units there need action, so one unit does not swing the picture.

Checked against the official statistics

Counted by year, our copy of the register matches the Government’s published table of non-domestic certificates within 1.5% in every year from 2013 to 2025.

Spotted a mistake?

Tell us at data@unlettable.co.uk.