Three Numbers to Check Before Going Full-Time on Your Side Hustle

The decision to leave your job for a side hustle reduces to three numbers. Getting them in order before you give notice is cheaper than figuring them out after.

Income replacement ratio

Your W-2 salary understates the total cost of going 1099, because your employer was covering things that didn't appear in your paycheck: half of Social Security and Medicare (7.65% of salary), a portion of your health insurance premium, any 401(k) match, and paid time off that was worth something.

Full-time freelance means paying both halves of FICA (15.3% combined), buying your own health coverage, and absorbing unpaid sick days and vacation directly from revenue.

The working rule: freelance income needs to reach 1.4x to 1.6x your W-2 salary to deliver roughly equivalent take-home and benefits. At $75,000/year W-2, the equivalent freelance gross is somewhere between $105,000 and $120,000.

Figure out how far your current side income is from that range.

Runway

Runway is how many months of expenses you can cover if revenue goes to zero.

Six months is the floor for most people making this leap. New full-time freelancers consistently underestimate how long it takes to build stable, recurring monthly revenue. One strong client is a start. Three months of good revenue isn't yet a pattern.

Use your actual monthly expenses. If your current spend is $4,200, that's the multiplier. Mentally trimming it to $3,000 because you could theoretically cut doesn't count until those cuts are made. At $4,200/month, six months of runway is $25,200, held separately from retirement accounts that carry withdrawal penalties.

Revenue baseline

Three consecutive months clearing the income replacement ratio. Not an average across three months. Three in a row.

The test is consistency. A business with $6,000 in January, $1,400 in February, and $7,800 in March averages fine on paper but shows feast-or-famine dynamics. That variance is harder to manage when the salary stops. Recurring retainer clients or reliable rebooking patterns are what the baseline measures.

If you're not clearing the ratio for three consecutive months, the number to build before quitting is monthly retainer volume, not raw revenue.

Health insurance

If you're on an employer plan and pay $200/month, your employer is likely covering $500–$600/month on top of that. That number doesn't show up on a pay stub, which is why it's easy to miss when building the replacement math.

ACA marketplace plans for a healthy person in their 30s typically run $350–$550/month before subsidies. COBRA continuation of your current plan runs $500–$800/month — same coverage, but you absorb the full premium the employer was carrying.

If your income in the transition year falls below 400% of the federal poverty level ($60,240 for a single person in 2026), the premium tax credit can bring marketplace costs down meaningfully. Above that threshold, you're paying full price.

Build the real insurance number into your replacement ratio from the start. The gap between "$200/month now" and "$450/month on the marketplace" is $3,000/year of freelance income that needs to exist before the comparison is fair.

The decision

When runway exceeds six months and revenue has cleared the replacement ratio for three consecutive months, the math supports the leap.

When runway is three months and revenue is inconsistent, it doesn't. Six months of W-2 paychecks spent building toward both thresholds is a reasonable trade.

The numbers aren't the complete picture. Some jobs become untenable before the math aligns. A partner's income changes the calculation. Some gigs hit a ceiling that part-time work can't break through without full attention. All of that is real.

The three numbers are still the foundation. Running them before the leap is the cheapest form of conviction available.

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If your income tracking isn't clean enough to run this math reliably, the 1099 Money System tracks revenue by client, expenses by Schedule C category, and makes the quarterly effective rate calculation take 15 minutes instead of an afternoon.

For informational purposes only. Not financial, tax, or legal advice.