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VAT Reclaim Calculator — How Much VAT Can I Reclaim on My Build?

Calculate how much VAT you can reclaim on a self-build or conversion to residential using the HMRC DIY Housebuilder Scheme (forms VAT431NB and VAT431C).

DIY Self-Build / Self-Managed Build

You must be building or managing the build yourself to claim

Total spent on materials including 20% VAT

Total paid to contractors (should be 0% VAT for new builds, 5% for conversions)

How We Calculate This

This calculator estimates the VAT you can reclaim under the HMRC DIY Housebuilder Scheme for new builds (form VAT431NB) and conversions to residential use (form VAT431C).

New Build Rules (VAT431NB)

  • Materials purchased by you at 20% VAT: full VAT reclaimable
  • Contractor services: should be zero-rated (0% VAT) — no VAT to reclaim

Conversion to Residential Rules (VAT431C)

  • Materials purchased by you at 20% VAT: full VAT reclaimable
  • Contractor services: charged at the reduced 5% rate — this 5% VAT is also reclaimable, so a conversion ends up effectively 0% VAT overall

How We Calculate

VAT is extracted from the inclusive price: VAT amount = price inc VAT / 6 (for 20% rate). For the 5% reduced rate: VAT amount = price inc VAT / 21. The reclaimable amount is then determined based on the property type and what is eligible.

References

  • gov.uk guidance: “Claim a VAT refund for a new home / for a conversion if you’re a DIY housebuilder” (the DIY refund scheme)
  • HMRC form VAT431NB: DIY Housebuilder new-build claim form
  • HMRC form VAT431C: DIY Housebuilder conversion claim form
  • HMRC VAT Notice 708: Buildings and Construction (contractor zero-rate for new builds, 5% reduced rate for conversions)
  • HMRC manual VCONST24000 (DIY builders and converters refund scheme; six-month time limit per VCONST24550)

Frequently Asked Questions

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Last updated: February 2026

Verified against UK standards · estimates only, confirm with your supplier.