Your side hustle is ready when it's costing you to keep the job

Quick answer: Don't quit when the business matches your salary. Quit when it reliably covers your replacement number (salary plus everything your employer quietly pays for), you're turning work away, no single client could sink you, and you've got at least six months of household expenses in the bank.

The moment usually shows up around 10:40 on a weeknight. The kids are down, the dishwasher's running, and you're writing a quote you don't want to send because you already have three jobs due Friday. And you think it: if I didn't have the day job, I could take this one.

That thought is right about half the time. The other half, it's how a good little business turns into a very hard year.

Matching your salary is the wrong finish line

Most women use the obvious test. The job pays $60,000, and when the business brings in $60,000, it's time.

It isn't. That $60,000 was never the whole paycheck. Your employer pays half of your Social Security and Medicare, which is 7.65 percent of your wages. Once you're self-employed in the US, you pay both halves through self-employment tax, a combined 15.3 percent on your net earnings. In Canada, you pick up both sides of your CPP contributions.

Then there's the stuff nobody itemizes. The health plan. The 401(k) match. Paid holidays. The laptop and phone the company bought. The two weeks you took at the lake last summer and still got paid for. Self-employed, a week off is a week of zero income.

So the business doesn't have to match your salary. It has to match your salary plus all of that. The gap is almost always bigger than people expect.

Work out your replacement number

Do this on paper, with your last pay stub and benefits statement in front of you.

• Start with your gross annual salary.
• Add the employer's half of payroll tax (7.65 percent in the US).
• Add what health coverage will actually cost you, whether from the marketplace or the extra premium to move onto your husband's plan. Get a real quote. Don't guess.
• Add the retirement match you'll lose.
• Add the business costs you currently get free: software, equipment, liability insurance, a phone line.
• Divide the total by 46 weeks, not 52. You'll get sick, the kids will get sick, and you'll want Christmas.

That weekly figure is what your business has to net, after its own expenses, week in and week out. Not in your best month. On average.

Look at it for a minute. It's usually sobering. It's also the most useful number you'll ever write down about this business.

The signals that actually mean go

Revenue alone won't tell you. These will:

• You're turning work away. Not once. Regularly. Referrals are landing faster than you can say yes, and you've started a waitlist without meaning to.
• The work comes to you. Most new clients arrive by referral or come back on their own. If every dollar still depends on you hustling for it, full-time just means hustling harder.
• No client is more than about a quarter of your income. One big client feels like security. It's actually a boss who can fire you with an email.
• You've got six months of household expenses saved. Household, not business. If your husband's income is steady, six months is a sensible floor. If you're the main earner, or his work is seasonal, go longer.
• You raised your prices and people still said yes. More on that one next, because it's the step most women skip.

If you can check all five, you're not taking a leap. You're making a transfer.

Raise your prices while you still have a paycheck

This is the contrarian bit, and it matters most.

Women tend to plan the price increase for after they go full-time, when they "need" the money. Backwards. The day job is the safest negotiating position you'll ever have. If a client walks, the mortgage still gets paid. Once you've quit, every client who balks at a new rate feels like a threat to the grocery budget, and you'll cave.

So raise rates now. Give existing clients 60 days' notice in writing. Quote new clients the new rate from the first conversation. Some will leave. The ones who stay are telling you what the business is really worth.

A hypothetical, to make it concrete. Say a bookkeeper named Megan works evenings and Saturdays for 11 small contractors at $250 a month each. That's $33,000 a year, and her replacement number comes out around $78,000. By the salary test she's nowhere close. But she's turning away two referrals a month.

So she moves existing clients to $300 and quotes new ones at $350. One client leaves. By fall she has 10 clients at $300 and 8 new ones at $350, which is $5,800 a month, or about $69,600 a year. That's still part-time hours, with capacity to spare once the day job's gone. Now the math works. It worked because she raised prices before she jumped, not after.

Have the kitchen-table conversation first

Your husband should hear the plan before your boss does. Not as a courtesy. As a partner.

Talk about the ugly quarter. What gets cut if March is slow? Who covers school pickup on the days a client meeting runs long? What does the household budget look like on his income alone for a few months?

And say the thing plainly: working from home isn't childcare. If you've got little ones, you'll need real help, even part-time. Grandma two mornings a week, a preschool schedule, a sitter. Women who plan to "work during naps" run a business that stays nap-sized.

Serve your family first. That's the reason you're doing this. But hold the line with everyone else. The client who texts at 9 p.m. on a Sunday gets an answer Monday at nine. The neighbor who figures you're "just home" and asks you to wait for her furnace repair guy gets a kind no. You're not being difficult. You're at work.

Leave the job better than you found it

How you walk out is part of the business plan.

Give more notice than the minimum if you can manage it. Write down everything you do, where the files live, which vendor needs a call every quarter. Offer to train your replacement. Stay late the last week and finish the ugly project nobody wants.

Read your employment agreement for any non-compete or non-solicitation clause, and have an employment attorney look at it before you give notice. Don't take the company's clients with you, even the ones who'd happily follow.

A former boss who respects you is one of the best referral sources you'll ever have. Plenty of home businesses land their first big client from the job they just left, because they left it well.

The first April is where people get hurt

When you're employed, taxes come out of each check. When you're self-employed, nobody withholds a dime, and the IRS expects estimated payments four times a year. Miss them and you can owe penalties on top of the tax.

Open a separate business checking account the week you decide, if you haven't already. Every time a client pays, move a set percentage into a savings account you don't touch. Many accountants suggest something between a quarter and a third of what comes in, but yours should give you the real figure for your situation.

Meet with a CPA before you quit, not the following March. Ask about quarterly payments, whether your structure makes sense, and retirement options for the self-employed, like a SEP IRA or a solo 401(k). An hour of their time now costs a lot less than one surprise tax bill. This is general education, not tax advice. Your accountant's word beats anything you read online, including this.

Full-time doesn't have to mean big

Somewhere along the way, going full-time and going big got tangled together. They're different decisions.

You can run a full-time business on 30 hours a week and still be out the door by 3:00. You can cap your client list at a number that pays the replacement figure and not one past it. You can say no to the hire, the office, and the expansion that would make it "real." It's already real if it pays the bills and leaves you enough of your life.

Build it big enough to pay like a job. Keep it small enough to make the bus stop.