Model Monthly Side Income
What to Measure Before Scaling
| Metric | Formula | Why it matters |
|---|---|---|
| Gross revenue | Paid hours × rate | Top-line income before any cost or tax |
| After-expense cash | Gross revenue − business expenses and fees | Closer to operating cash, but still before tax |
| Effective hourly amount | After-expense cash ÷ paid and unpaid work hours | Shows the effect of admin, proposals, travel, and waiting |
| Collection timing | Invoice date to cleared payment | Affects runway even when revenue looks adequate |
Federal Tax Basics
The IRS states that the self-employment tax rate is 15.3%, consisting of Social Security and Medicare components, with wage-base and additional-Medicare rules that can change the actual calculation. It applies to net earnings, not simply the model’s gross revenue. Source: IRS self-employment tax guidance.
People who are self-employed generally pay tax through estimated payments when withholding is not sufficient. Use the IRS withholding and estimated-tax guidance or a qualified tax professional rather than applying a flat “set aside” percentage from an article.
Unemployment Benefits and Reporting
Benefit rules and the treatment of work or earnings vary by state and program. Report work and income exactly as required on each certification. Check the official state unemployment agency before accepting a project or assuming how earnings will affect a benefit. Keep contracts, time records, invoices, expenses, and payment dates.
Build a Defensible Rate
Start with the service scope, client value, market quote, platform fee, direct costs, non-billable time, and payment risk. Run a paid pilot, then compare the modeled effective hourly amount with actual results. Do not use a national “skills-based” range as a substitute for evidence in your market.
Methodology and Limits
The calculator uses 52 ÷ 12 weeks per month. Gross monthly revenue = billable hours × rate × 52 ÷ 12. After-expense cash subtracts the percentage entered. Effective hourly amount divides after-expense cash by all paid and unpaid hours. It assumes consistent weekly hours and full collection.
Primary resources reviewed July 23, 2026: IRS self-employment and estimated-tax guidance linked above. Educational only; not tax, benefits, employment, or financial advice.