This calculator helps you decide how to split a windfall, such as a bonus, inheritance, tax refund or other lump sum, across debt, savings, investing and spending, so the money makes lasting progress instead of quietly disappearing into everyday spending. You enter the windfall amount and set four percentages: how much goes to paying off debt, how much tops up your emergency savings, how much you invest, and how much you keep to spend or enjoy. As you type, the calculator works out the dollar amount for each category and displays them in a results table, while a running note confirms whether your percentages add up to 100% or how far off you are. The page also walks through a worked example on a $15,000 windfall split 40% debt, 20% savings, 30% investing and 10% spending, showing how the total breaks down into $6,000, $3,000, $4,500 and $1,500. Use it whenever an unexpected sum lands in your account and you want a plan before it gets absorbed into ordinary spending. As a general guide, clearing high-interest debt first usually delivers the best guaranteed return, an emergency buffer adds security, and investing builds wealth over time, though the right mix depends on your own debts, savings and goals. This is a planning tool to help you allocate money deliberately, not financial advice, so adjust the split to fit your circumstances.
| Purpose | Share | Amount |
|---|
Clearing high-interest debt is usually the best guaranteed return. Adjust the percentages to suit your debts, savings and goals; they should add to 100%. Estimate only, not financial advice.
The calculator applies each percentage to your windfall to show the dollars going to debt, savings, investing and spending, and checks the shares add to 100%. The order matters: clearing high-interest debt is usually the best guaranteed return, an emergency buffer brings security, investing builds the future, and a slice to enjoy keeps the plan realistic. Adjust the split until it fits your situation.
On a $15,000 windfall split 40% debt, 20% savings, 30% investing and 10% spending, that is $6,000 to debt, $3,000 to savings, $4,500 invested and $1,500 to enjoy. Every dollar has a job, so the windfall makes lasting progress rather than quietly disappearing.
If you've found a bug, or would like to contact us, or learn more about James Graham and Calculate.co.nz.
Calculate.co.nz is partnered with Interest.co.nz for New Zealand's highest quality calculators and financial analysis.
Calculate.co.nz is the sister site of CalculatorHub.com, the world's largest calculator website by tool count.
All calculators and tools are provided for educational and indicative purposes only and do not constitute financial advice.
Calculate.co.nz is proudly part of the Realtor.co.nz group, New Zealand's leading property transaction literacy platform, helping Kiwis understand the home buying and selling process from start to finish. Whether you're a first home buyer navigating your first property purchase, an investor evaluating your next acquisition, or a homeowner planning to sell, Realtor.co.nz provides clear, independent, and trustworthy guidance on every step of the New Zealand property transaction journey.
Calculate.co.nz is also partnered with Health Based Building and Premium Homes to promote informed choices that lead to better long-term outcomes for Kiwi households.
Calculate.co.nz is hosted in Auckland via SiteHost new Zealand.
All content on this website, including calculators, tools, source code, and design, is protected under the Copyright Act 1994 (New Zealand). No part of this site may be reproduced, copied, distributed, stored, or used in any form without prior written permission from the owner.
About & trust: Why Calculate is NZ's most comprehensive · By the Numbers · How we compare · Editorial standards · How we keep data current · NZ finance glossary · Research & data · Financial literacy NZ · About · Privacy policy · Terms of use
Reviewed and maintained. Last reviewed 2026-07-02 and checked on a twice-monthly cycle against IRD, RBNZ and Stats NZ. How we keep data current.
© 2026 Calculate.co.nz. All rights reserved. Building free NZ calculators since 2011.