CIS mortgage calculator: gross pay vs your net take-home
CIS deductions confuse mortgage assessments: HMRC takes 20% (registered), 30% (unregistered) or 0% (gross payment status) off your pay before you see it, but most lenders that engage with CIS income assess you on the gross figure. See both numbers side by side, and which of the 13 lenders we track use a gross-favourable route, a full self-employed route, or publish no position at all — based on verified lending criteria (verified 2026-07-13).
This is an information tool, not advice: it doesn't give a recommendation, a decision in principle, or a guarantee any lender will lend to you.
Worked example: £400/day, 5 days a week, CIS-registered
A CIS subcontractor registered with HMRC (20% deduction), invoicing £400/day.
Lenders that assess CIS income use your £2,000/week GROSS figure — not the £1,600/week you actually receive after the 20% CIS deduction. 3 of 13 lenders we track apply a day-rate-style gross route to CIS income.
- Kensington: £96,000 assessed (gross) — the highest assessed figure here, on its day-rate route (CIS is filed under its complex-income category).
- Barclays: not on the gross route — Assessed as self-employed (2 years' accounts) — not a gross-CIS route.
Only 3 of 13 lenders we track apply a gross, day-rate-style route to CIS income at all — see the full per-lender position in our CIS contractor guide.
Change the inputs below to model your own numbers.
Your invoiced day rate, before any CIS deduction. Between £0 and £10,000.
Deduction rates verified against GOV.UK (Construction Industry Scheme).
FAQ
Does the CIS deduction lower what a lender will lend me?
Not at the lenders that use a gross route — the deduction is a tax mechanic, not a fall in your actual earning power, so NatWest, Halifax, Kensington and Skipton all assess figures at or close to your gross pay. It only bites at lenders that route CIS income to full self-employed underwriting, where two or three years' declared (post-deduction) profit becomes the assessed figure instead.
What if a lender's CIS position isn't published anywhere?
Several lenders on this panel — Coventry BS, Leeds BS and Metro Bank among them — simply don't address CIS in their published intermediary criteria. That's not the same as a decline; it means confirming directly with the lender or a whole-of-market broker before you apply is genuinely necessary, not just cautious wording.