Cgt Cost Base · Koste Knowledge Base

What costs are excluded from my property cost base?

Published 26 June 2026 · Last updated 26 June 2026

Quick Answer

Costs already claimed as deductions, private expenses, some repair costs and certain capital works deductions may not be included in the cost base in the same way. Your accountant needs to review the records carefully before calculating CGT.

Not every property cost increases the CGT cost base.

Costs may be excluded or adjusted if:

They were already claimed as deductions
They relate to private use
They are repairs, not capital improvements
They are capital works already claimed
They are not connected with acquisition, improvement or disposal
They are not supported by evidence

Common problem areas:

Repairs vs improvements
Capital works deductions
Interest and holding costs
Private-use periods
Depreciation
Mixed-use property
Trust or SMSF ownership

Koste.ai can help identify cost categories, but accountants determine the final tax treatment.

Frequently Asked Questions

Can I include repairs in cost base?

Repairs already claimed as deductions may not be included the same way.

Do capital works deductions affect cost base?

Yes, they may reduce the cost base.

Can private costs be included?

Private costs are generally treated differently.

Who decides final treatment?

Your accountant or tax adviser.

Can Koste.ai help separate costs?

Yes. Koste.ai can organise records for accountant review.

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Written by Koste Team · Koste Chartered Quantity Surveyors · AIQS Member · RICS Member · TPB Registered · 1300 669 400 · info@koste.ai