Calculator Inputs
Example data table
| Person | Income | Deductions | Weight | Net income | Proportion | Contribution on 3,000 |
|---|---|---|---|---|---|---|
| Alex | 5,200 | 300 | 1.00 | 4,900 | 49.75% | 1,492.39 |
| Blake | 3,400 | 250 | 1.00 | 3,150 | 31.98% | 959.39 |
| Casey | 1,900 | 100 | 1.00 | 1,800 | 18.27% | 548.22 |
Formula used
This calculator converts each participant's income into an effective share, then allocates the chosen amount according to that share.
Base income_i = Gross income_i when gross mode is selected
Base income_i = max(Gross income_i - Deductions_i, 0) when net mode is selected
Effective income_i = Base income_i × Weight_i
Proportion_i = Effective income_i ÷ Sum of all effective incomes
Contribution_i = Proportion_i × Allocation amount
Gap vs equal share_i = Contribution_i - (Allocation amount ÷ Active participants)
A participant becomes active only when effective income is greater than zero.
How to use this calculator
- Enter the total amount you want to divide.
- Choose whether proportions should use gross or net income.
- Add each participant's income, deductions, and optional weight factor.
- Select decimal precision and rounding behavior for final contributions.
- Submit the form to view ratios, percentages, and allocated shares.
- Download the result table as CSV or PDF for records.
FAQs
1. What does income proportion mean?
Income proportion is each participant’s share of the total effective income. It shows how much of a shared cost, target, or contribution should reasonably belong to each person.
2. When should I use gross income mode?
Use gross mode when you want to compare earnings before taxes, payroll deductions, or other reductions. It is helpful for simple planning or when deduction data is incomplete.
3. When is net income mode better?
Net mode is better when fairness depends on spendable income. It subtracts deductions first, so each person’s contribution reflects money that is actually available after reductions.
4. Why would I change the weight factor?
Weights let you adjust the raw income basis. You might raise a weight for a higher expected contribution or lower it when a participant has special obligations.
5. Does the calculator work for more than expenses?
Yes. You can use it for savings targets, shared investments, family budgets, team distributions, donation planning, or any amount that should follow income-based proportions.
6. Why is someone missing from the active result table?
If active-only display is selected, participants with zero effective income are hidden. Their calculated share is zero, so they do not affect the proportional allocation.
7. What does gap versus equal share show?
It compares the proportional contribution against a simple equal split. Positive values mean someone pays more than an even split, while negative values mean less.
8. Are exported CSV and PDF files based on current results?
Yes. The export buttons use the result table currently shown on the page, so they reflect your latest submission, precision, rounding mode, and display choices.