IR330C Withholding Rate Chooser

What the IR330C is for

The IR330C is Inland Revenue's Tax rate notification for contractors. You use it if you're receiving schedular payments, meaning payments for a specific type of work listed in Schedule 4 of the Income Tax Act 2007, rather than salary or wages as an employee. It tells whoever is paying you which withholding tax (WT) rate to deduct before they pay you. You complete a separate IR330C for each source of contracting income, sign it, and hand it to your payer. It is not sent to Inland Revenue; the payer keeps it with their business records for seven years after your last payment.

Schedule 4 standard rates by activity

Every schedular payment activity has a standard rate set out on the back of the IR330C form. The table below is the full list currently in force.

Choosing your own rate instead of the standard rate

You don't have to use the standard rate for your activity. The IR330C lets you nominate your own rate, provided it isn't below the legal minimum. If you're a New Zealand tax resident and not on a temporary entry class visa, you can go as low as 10%. If you're a non-resident for tax purposes, or you hold a temporary entry class visa, the minimum is 15%. There's no upper limit beyond a practical ceiling of 40%. A small number of activities don't allow an election at all: non-resident entertainers and professional sportspeople visiting New Zealand are fixed at 20% regardless of what they'd prefer. If the minimum rate that applies to you would still mean paying far more tax than you actually owe, for example because of large deductible expenses, you can apply for a tailored tax rate (TTR) through myIR or an IR23BS form, which Inland Revenue calculates specifically for your situation.

The 45% no-notification rate

If you don't give your payer a completed IR330C, or you leave out required details like your IRD number or signature, the payer has no choice but to deduct tax at the no-notification rate. For almost everyone that rate is 45%, deliberately set well above typical marginal tax rates so there's no incentive to avoid filing the form. The one exception is non-resident contractor companies, where the no-notification rate is 20% instead. Being stuck on 45% ties up a large amount of your cash until you file your end-of-year return and claim the excess back, so it's worth submitting a valid IR330C as soon as you start contracting for someone new.

Worked example: choosing between the standard and a nominated rate

Aaron works as a self-employed labourer under a labour-only contract in the building industry (activity 8, standard rate 20%). He expects to earn $70,000 in gross contracting income this year, before any GST. Using the 2026/27 income tax brackets, tax on $70,000 works out as: $15,600 at 10.5% is $1,638.00, the next $37,900 (to $53,500) at 17.5% is $6,632.50, and the remaining $16,500 (to $70,000) at 30% is $4,950.00. That's a total income tax bill of $13,220.50, an average rate of 18.89%.

If Aaron uses the standard 20% rate, his payer withholds $70,000 × 0.20 = $14,000.00 over the year, which is $779.50 more than his plain income tax bill of $13,220.50. That means, ignoring any deductible expenses and ACC levies (which are billed separately), he'd be due a small refund of roughly $779.50 when he files his return.

Aaron also has around $8,000 of deductible expenses (tools, a work vehicle, insurance), which lowers his taxable profit to $62,000. Tax on $62,000 is $1,638.00 + $6,632.50 + ($8,500 × 0.30 = $2,550.00) = $10,820.50. If he instead nominates a rate of 15% (a valid choice, since 15% is above his 10% minimum as a New Zealand tax resident), his payer withholds $70,000 × 0.15 = $10,500.00, only $320.50 short of his actual $10,820.50 bill, a much closer match than the standard rate once his real expenses are accounted for. Contractors with significant deductible expenses often find a nominated rate below the standard rate keeps more cash in hand through the year without leaving a large bill at tax time.

Had Aaron not filed an IR330C at all, his payer would have withheld tax at 45%, or $31,500.00 over the year, more than double what he actually owes even before deductions, locking up cash he wouldn't see again until his refund came through.

ACC levies and GST are separate

Your WT deduction is for income tax only. ACC does not collect the earner's levy through your schedular payment withholding. As a contractor, ACC invoices you directly for your levies, generally based on the earnings you declare in your income tax return, so budgeting for that invoice separately from your WT rate matters. If you're GST-registered, WT is also calculated on the GST-exclusive portion of your invoice; the GST itself is paid to you in full and accounted for separately in your GST return. Our Schedular Payments Calculator walks through a single invoice in full, including the GST split and the net amount you actually receive.

Who this calculator is for

This tool is for anyone starting contracting work covered by Schedule 4, such as builders' labourers, cleaners, company directors, entertainers, shearers, or labour-hire workers, who needs to fill in an IR330C and isn't sure whether to use the standard rate or nominate their own. It's also useful if your income or expenses have changed and you want to check whether your current rate still fits, or if you're deciding whether the cash-flow benefit of a lower nominated rate is worth the risk of a bigger bill at year-end.

What this calculator assumes

• Standard rates and the no-notification rate are taken from the current IR330C form and Schedule 4 of the Income Tax Act 2007.
• The income tax comparison uses only the 2026/27 income tax brackets on your entered gross contracting income; it does not model deductible expenses, other income, ACC levies, GST, or student loan repayments.
• Your minimum self-elected rate is based on the residency answer you give; special tailored tax rate arrangements are not modelled.
• Results are indicative only. Your actual year-end tax position depends on your full income, expenses and any other tax obligations.

Frequently Asked Questions

What is the IR330C form and who needs to complete it?

The IR330C is the Tax rate notification for contractors. You complete it if you're a contractor receiving schedular payments, an activity listed in Schedule 4 of the Income Tax Act 2007, rather than an employee. You give the completed form to whoever pays you. It isn't sent to Inland Revenue; the payer keeps it on file for seven years.

What tax rate should I choose on my IR330C?

You can use the standard rate for your activity, from 10.5% to 33%, or nominate your own rate. A sensible approach is to estimate your income tax for the year on your expected contracting income and choose a rate close to that average, so you don't end up with a large bill or too much cash tied up until your refund arrives.

What is the lowest rate I can elect for myself?

If you're a New Zealand tax resident and not on a temporary entry class visa, the lowest rate you can elect is 10%. If you're a non-resident for tax purposes, or hold a temporary entry class visa, the lowest is 15%. Non-resident entertainers and professional sportspeople visiting New Zealand have a fixed rate of 20% with no election available.

What happens if I don't complete an IR330C?

Your payer must deduct tax at the no-notification rate of 45%, except for non-resident contractor companies, where it's 20%. That's far higher than most contractors actually owe, so you'll be over-taxed until you file your end-of-year return and claim the excess back.

What is the standard rate for company directors' fees?

33%, the same rate as examiners' fees, honoraria and public office holders' fees. That's often above a director's real marginal tax rate if the directorship is only a small part of their income, which is why many directors nominate a lower rate.

Does my WT deduction cover my ACC levies?

No. WT covers income tax only. ACC invoices contractors directly for earner levies, generally based on the income declared in your tax return, so budget for that separately from whatever rate you put on your IR330C.

Do I still need to file a tax return if my payer withholds WT?

Yes. You generally still need to file an income tax return (an IR3), declare the gross schedular payments as income, and claim the WT already deducted as a tax credit. You'll get a refund if too much was withheld, or pay the difference if too little was.

What is a tailored tax rate, and when would I need one?

A tailored tax rate (TTR) is a rate Inland Revenue calculates specifically for you, useful if even the minimum standard rate would over-tax you because of significant deductible expenses. You apply through myIR or an IR23BS form and show the resulting certificate to your payer. Non-resident contractors use a different application process.

Related NZ contractor and tax calculators

• Schedular Payments Calculator: calculates the WT tax, GST split and net amount for a single invoice.
• Tax Reserve Per Invoice Calculator: works out how much to set aside from each invoice for income tax, ACC and student loan.
• Contractor True Cost Calculator: quantifies the leave, KiwiSaver and ACC you give up going contracting.
• Side Hustle Income Tax Calculator: tax on extra income earned alongside a main job.
• Business Income Tax Calculator: full-year income tax estimate for sole traders and companies.

Official NZ sources

This calculator is built from primary New Zealand sources. Always confirm your own position against the official source or a registered tax agent:

• Inland Revenue (IRD): IR330C, Tax rate notification for contractors
• Inland Revenue (IRD): Schedular payments overview
• New Zealand Legislation: Income Tax Act 2007, Schedule 4