NZ IRD Kilometre Rate & Square Metre Home Office Deduction Calculator
Calculate IRD Tier 1 & Tier 2 vehicle kilometre rates (petrol, hybrid, EV) and the $53.10/m² home office expense deduction for NZ sole traders and businesses.
Calculate IRD Tier 1 & Tier 2 vehicle kilometre rates (petrol, hybrid, EV) and the $53.10/m² home office expense deduction for NZ sole traders and businesses.
Calculate IRD Tier 1 & Tier 2 vehicle kilometre rates (petrol, hybrid, EV) and the $53.10/m² home office expense deduction for NZ sole traders and businesses. Calculate exact, penny-accurate projections compliant with 2026 Inland Revenue (IRD) • ACC • Reserve Bank of New Zealand (RBNZ) standards using Calconova's deterministic IEEE-754 (Decimal.js) calculation engine with instant breakdowns.
Vehicle mileage + Home office
@30% marginal tax rate
18,500 km (14,000 km Tier 1)
18 m² (12.9% ratio)
Motor powertrain and business kilometres driven.
IRD $53.10/m² rate and property cost apportionment.
Statutory deductions and cash tax reductions.
\text{Vehicle Deduction} = \min(km, 14000) \times \text{Tier 1 Rate} + \max(0, km - 14000) \times \text{Tier 2 Rate} \\
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\text{Home Office Deduction} = (\text{Office } m^2 \times \$53.10) + \left(\frac{\text{Office } m^2}{\text{Total Home } m^2}\right) \times (\text{Mortgage Interest/Rent} + \text{Rates} + \text{Insurance}) \\
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\text{Tax Cash Savings} = (\text{Vehicle Deduction} + \text{Home Office Deduction}) \times \text{Marginal Tax Rate}Under IRD operational guidelines, business mileage is claimed using a 2-tier system: Tier 1 for the first 14,000 km ($1.04/km petrol/diesel/hybrid, $0.85/km EV) and Tier 2 for excess kilometres ($0.35, $0.21, or $0.19). For home offices, IRD allows $53.10 per m² per year for utilities/operational costs, plus an apportioned share of rent or mortgage interest, rates, and insurance based on the office area ratio.
All calculations, amortizations, and scenario projections displayed on this page are strictly for informational and educational purposes. Nothing herein constitutes investment, financial, tax, or legal advice. Actual Reserve Bank of New Zealand (RBNZ) interest rates, IRD PAYE brackets, ACC Earner's Levy, KiwiSaver regulations, and lender criteria may vary. Calconova explicitly disclaims all liability for any decisions taken based upon these calculations. Consult a qualified financial advisor, CPA, or official Inland Revenue documentation prior to executing financial commitments.
Tier 1 covers both fixed costs (vehicle depreciation, insurance, warrant of fitness) and running costs, and applies to the first 14,000 business km per tax year. Once you exceed 14,000 km, fixed costs are deemed covered, so Tier 2 applies to reflect only incremental running costs (fuel/power, maintenance).
The $53.10/m² IRD standard rate covers electricity, gas, heating, telephone, internet, and general cleaning without needing to keep detailed utility bills. However, rent, mortgage interest, council rates, and house insurance are claimed separately based on the square metre percentage.
No. Only the mortgage interest component of your repayments can be apportioned and claimed. Mortgage principal repayments are capital in nature and are not tax-deductible.
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