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Mixed-Use Asset / Airbnb Tax Calculator

Calculate income tax and GST on a NZ Airbnb/bach rented part-time. IRD mixed-use formula: rental days ÷ total used days = deductible %.

By Konstantin IakovlevPublished 28 March 2026Last reviewed
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About this calculator

This calculator implements mixed-use asset rules + short-stay standard cost from Inland Revenue (IRD). Last consulted 18 May 2026. Verify the figures yourself by following the link.

NZ short-stay accommodation tax rules

Mixed-use rules + 2024 Airbnb GST changes
  • Short-stay standard cost: $65/night (no tax if income ≤)
  • GST registration threshold: $60,000 turnover/yr
  • Airbnb GST (from 1 Apr 2024): 15% collected by platform
  • Airbnb flat-rate credit (non-GST): 8.5% returned to host
  • Mixed-use formula: Rental days ÷ total used days
  • Vacant days: Don't count in either bucket

Source: IRD — Short-stay accommodation

Disclaimer

This calculator provides estimates for general information purposes only. Results should not be relied upon as professional financial, tax, or legal advice. Tax rates and thresholds are based on publicly available IRD data and may change. Always consult a qualified tax agent or financial adviser for advice specific to your circumstances.

How NZ mixed-use Airbnb tax works

Mixed-use rules apply when a property is used part rental, part personal. Deductible expenses are apportioned.

  1. 1

    Calculate deductible %

    Deduct_% = rental_days ÷ (rental_days + personal_days)

    Vacant days don't count in either bucket.

  2. 2

    Apportion expenses

    Deductible_expenses = (rates + insurance + interest + maintenance) × deduct_%

    Cleaning + laundry between guests = 100% deductible.

  3. 3

    Net rental income

    Net = gross_rental − deductible_expenses

    Losses are quarantined under residential ring-fencing rules (no offset against salary).

  4. 4

    Income tax on net

    Tax = net_rental × marginal_rate

    At your top marginal bracket.

  5. 5

    GST adjustments (from 1 Apr 2024)

    If not GST registered: Net_GST_credit = gross × 8.5 ÷ 108.5 (Airbnb pays you)

    If GST registered: you charge 15%, claim back input GST.

Worked example

Inputs: 60 rental days + 20 personal, $18k gross, $6k expenses, $22k interest, not GST

Result: Deductible 75%. Expenses deductible $21k. Net rental −$3k (quarantined). 8.5% credit ~$1,410.

Frequently Asked Questions

What are the NZ mixed-use asset rules?
If you rent out a holiday home, bach, or spare bedroom on Airbnb/Bookabach part-time, mixed-use rules apply: deductible expenses (rates, insurance, mortgage interest, maintenance) are apportioned based on rental days ÷ total used days. Vacant days don't count. Example: 60 rental + 20 personal = 75% deductible. Standard-cost option ($65/night, 2025-26) exempts low-income hosts from filing. Source: IRD.
Do I need to register for GST as an Airbnb host?
Mandatory if your annual Airbnb income exceeds $60,000. Below that, registration is optional. From 1 April 2024 Airbnb collects 15% GST automatically on all NZ bookings; if you're NOT GST registered, Airbnb passes you back an 8.5% flat-rate credit to compensate for GST on your costs. Source: IRD.

The mixed-use asset / Airbnb tax calculator works out income tax and GST on a NZ holiday home or spare room rented part-time, using IRD's mixed-use asset apportionment formula and the platform GST rules that took effect on 1 April 2024.

How this calculator works

A bach or home that is sometimes rented and sometimes used privately is a "mixed-use asset" under IRD rules. Your deductible share of expenses is rental days ÷ (rental days + personal days) — vacant days do not count in either bucket. That percentage is applied to shared costs such as rates, insurance, mortgage interest, and general maintenance, while costs caused solely by guests (cleaning between stays, listing fees) stay 100% deductible. Losses on residential property are usually ring-fenced: they carry forward against future rental income rather than offsetting your salary. Since 1 April 2024, booking platforms such as Airbnb must collect 15% GST on every stay; if you are not GST-registered the platform passes you a flat-rate credit of 8.5% of the tariff, and if you are registered you account for GST yourself. The short-stay standard-cost method (about $65 per night) can exempt small-scale room rental entirely.

NZ short-stay tax rules

Mixed-use apportionmentRental days ÷ (rental + personal days)
Vacant daysCount in neither bucket
Guest-only costs (cleaning, listing fees)100% deductible
Residential loss ring-fencingLosses carry forward, no salary offset
Platform GST (from 1 Apr 2024)15% collected by Airbnb/Bookabach
Flat-rate credit if not GST-registered8.5% of tariff returned to host
GST registration threshold$60,000 turnover per year
Short-stay standard cost~$65/night exempt method

Worked Examples

Bach: 60 rental days, 20 personal days, $18,000 gross rent, $6,000 running costs, $22,000 mortgage interest, not GST-registered

Tax loss of ≈ $3,000 (ring-fenced) plus a GST flat-rate credit of ≈ $1,410.

  1. Deductible share: 60 ÷ (60 + 20) = 75%
  2. Deductible expenses: ($6,000 + $22,000) × 75% = $21,000
  3. Net rental: $18,000 − $21,000 = −$3,000 → ring-fenced, carried forward
  4. Platform GST credit: $18,000 × 8.5 ÷ 108.5 ≈ $1,410

City apartment: 120 rental days, 30 personal days, $32,000 gross, $8,000 running costs, $18,000 interest, owner on 33% rate

Taxable profit $11,200 → income tax ≈ $3,696.

  1. Deductible share: 120 ÷ 150 = 80%
  2. Deductible expenses: ($8,000 + $18,000) × 80% = $20,800
  3. Net rental: $32,000 − $20,800 = $11,200
  4. Tax at 33%: $11,200 × 33% ≈ $3,696

Built and maintained by Konstantin Iakovlev. Data sourced from the IRD and official New Zealand government sources.

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