What Information Do I Need to Use BudgetDuo?

To use BudgetDuo, you need three things ready before you start: each partner's income (or whatever financial figure you want the split based on), a list of your shared expenses with their amounts, and a browser with JavaScript enabled. BudgetDuo is a web app that calculates how much you and your partner should each contribute toward shared expenses, so the accuracy of your result depends entirely on the numbers you bring to it.

The inputs you should have on hand

1. Each partner's income

The core of a proportional split is comparing what each of you earns. Before opening the site, decide:

• Which figure to use — gross (pre-tax) or net (take-home) pay. Pick one and use it consistently for both partners, or the ratio will be skewed.
• The time period — monthly and annual are the most common. Just make sure both partners are expressed in the same period.
• Whether income is stable — if one or both of you have variable income (freelance, commission, tips), decide whether to use an average, a recent month, or a conservative baseline.

2. Your shared expenses

List the expenses you want to split, not just a single total. Typical categories include:

Having individual line items helps you later if you want to exclude something or adjust a category.

3. A JavaScript-enabled browser

BudgetDuo is a JavaScript app. Its page states plainly: "You need to enable JavaScript to run this app." If you open it and see only a blank page or that message, JavaScript is disabled or blocked. Check your browser settings or any script-blocking extension before troubleshooting anything else.

What you do not need to prepare

• No account details are required to reach the calculator based on the available information.
• No bank login or linked accounts — you enter figures manually.
• No specific file format — plain numbers are enough.

How the pieces fit together

BudgetDuo takes the income figures to establish each partner's share of total household income, then applies that ratio to the shared expense total. For example, if one partner earns 60% of the combined income, their share of a $2,000 shared expense total would be $1,200.

This is why the two inputs must match in scope: if you enter one partner's net pay and the other's gross pay, the ratio — and therefore every contribution figure — will be wrong.

Common snags before you start

• Mismatched periods. One partner's monthly income against the other's annual income produces a meaningless split.
• Forgetting irregular expenses. Annual insurance or quarterly bills get missed if you only list monthly items. Either convert them to a monthly equivalent or track them separately.
• Blank page. Almost always JavaScript, not a broken site.
• Disagreement on the base figure. Settle gross vs. net and stable vs. averaged income before entering numbers, so you're debating the split rather than the inputs.

Once your income figures and expense list are ready and JavaScript is on, you have everything BudgetDuo needs to produce a contribution split.