Calculators

A full-time salary scaled to part-time hours

What a full-time salary is worth at fewer hours, gross and after tax.

The gross part is a proportion, and the useful part is what follows it: the take-home does not scale with the hours, because dropping to half time drops the salary out of the higher brackets. Someone going from full time to three days often keeps more than 60% of their take-home, and that is the number the decision actually turns on.

hourly_rate is the full-time salary over full-time hours times 52, which is the rate the job pays. Dividing the pro rata salary by the pro rata hours gives the same figure.

The Independent Earner Tax Credit defaults on, because part-time earnings are exactly the band where it is worth the most. Turn it off for someone on a main benefit, Working for Families or NZ Super.

post/v1/pro-rata-salary

Request

  • Base URL: https://api.calculate.co.nz
  • URL: https://api.calculate.co.nz/v1/pro-rata-salary
  • Auth: API key in header X-API-Key

Request body

full_time_salarynumber required

The advertised full-time annual salary.

full_time_hoursnumber

Hours a week the full-time role is based on.

your_hoursnumber

Hours a week actually worked.

kiwisaver_ratenumber

Employee contribution as a DECIMAL.

has_student_loanboolean

Whether repayments are deducted.

claim_ietcboolean

Whether the Independent Earner Tax Credit applies. Part-time earnings are exactly where it is worth the most, so it defaults on.

Example request

{
  "claim_ietc": true,
  "full_time_hours": 40,
  "full_time_salary": 90000,
  "has_student_loan": false,
  "kiwisaver_rate": 0.035,
  "your_hours": 24
}

Response

Gross at the reduced hours, and the take-home the website does not show.

disclaimerstring required

Scope and limits of this calculation.

Example response

{
  "disclaimer": "Estimate only. Assumes the salary scales strictly with hours, which an employment agreement may not. Take-home uses current year rates and the assumptions you gave. Not financial or employment advice.",
  "result": {
    "acc_levy": 945,
    "fortnightly": 2076.92,
    "fraction_of_full_time": 60,
    "full_time_hours": 40,
    "full_time_salary": 90000,
    "hourly_rate": 43.27,
    "income_tax": 8420.5,
    "kiwisaver_employee": 1890,
    "monthly": 4500,
    "pro_rata_annual": 54000,
    "student_loan": 0,
    "take_home_annual": 43264.5,
    "take_home_weekly": 832.01,
    "tax_year": "2026/27",
    "weekly": 1038.46,
    "your_hours": 24
  }
}

Changes

No recorded changes to this operation across all 1 revision of this API.