How to Do Payroll Yourself: Steps, Risks, and Deadlines

I ran my own payroll for about eighteen months. Two employees, one state, a spreadsheet I built myself, and a calendar with six dates on it. It worked, it cost nothing in fees, and I would tell a founder in the same position to do the same thing. I would also tell them when to stop, because I left it six months too late and paid for the privilege.

Doing payroll yourself is legal. Nothing in federal law requires software, a service, or an accountant, and the IRS has no opinion about who did the arithmetic as long as the numbers are right and the money arrives on the correct day. What catches people out is never the calculation. It is the gap between paying your people, which feels like the end of the job, and remitting the tax you withheld, which happens weeks later with nothing in your day to remind you.

This is the walkthrough for an employer without an HR department: the accounts that must exist before the first payday, the arithmetic, the deposit schedule the IRS assigns you without asking, the filings, what you keep, and the point where doing this yourself stops being worth it. I build the people and records tooling at FirstHR, an onboarding and HR platform rather than a payroll provider, so nothing here is a pitch for a payroll product. This is general information, not tax or legal advice.

Can You Legally Do Payroll Yourself?

Yes, and there is no threshold, license, or approval involved. No federal statute requires an employer to use payroll software or a payroll service, and no state conditions your right to employ people on outsourcing the paperwork. The obligations attach to the outcome rather than to the method.

People assume a provider makes them safe because it feels like handing over responsibility, and it does not. If a provider misses a deposit, the notice arrives addressed to your business, and the trust fund penalty regime reaches the individuals inside it. Software buys accuracy and reminders, not indemnity.

What you are really choosing is where the deadline discipline lives. A payroll system holds the calendar and updates the tax tables every January; doing it yourself makes both jobs on your own list.

What You Need Before the First Run

Five things have to exist before you can legally pay anyone, and two of them run on an agency's timetable rather than yours. The right moment to start is when you decide to hire, not the week the person arrives.

The federal number is the easy one. It is free, the online application issues it immediately, and the constraints are that the responsible party needs a valid taxpayer identification number and that you can obtain one per responsible party per day (IRS).

The state layer is where first paydays slip, because you need accounts in every state where an employee physically works rather than where your headquarters sits.

The reason this stage goes wrong is that it is a set of separate applications to separate agencies, each returning a number you will need later and none of them chasing you. Track it as one sheet with a date and a confirmation number against every line, and add a row to the second tab for every state where somebody physically works.

The Toolkit You Actually Need

Four things: the current IRS employer tax guide, the current withholding methods publication, a spreadsheet you trust, and a calendar with every deposit and filing date entered before you owe anything.

Publication 15 carries the rates, the deposit rules, and the retention expectations in one place (Internal Revenue Service). Its companion, Publication 15-T, carries the withholding methods and the tables you compute from, and it changes materially every January (IRS withholding methods). Working from last year's copy is the most common self-inflicted error in manual payroll.

The spreadsheet matters less than people think: one tab per pay period computing gross, deductions, withholding, and net, with a running year-to-date column that tells you when somebody crosses the Social Security wage base. The calendar is the part that actually keeps you compliant, and the part people build last or not at all. Enter twelve months of deposit dates and six federal filing dates on the day you set up, before a single deposit is owed.

Calculating Gross Pay

Gross pay is everything the employee earned for the period before a single deduction, and every other number depends on it. For salaried staff it is annual salary divided by the number of pay periods. For hourly staff it is hours actually worked at the agreed rate, plus overtime, plus bonuses, commissions, tips, retroactive adjustments, and taxable fringe benefits.

Overtime is the wrinkle that catches new employers. For non-exempt employees, federal law requires one and a half times the regular rate above forty hours in a workweek, and the regular rate is not the hourly wage. It absorbs non-discretionary bonuses, shift differentials, and commissions earned that week, spread back across the hours worked.

Then, before any tax calculation, subtract pre-tax deductions. The ordering is not cosmetic: a Section 125 health premium reduces the base for income tax and for Social Security and Medicare, while a traditional retirement contribution reduces the income tax base but not the other.

Hourly Payroll, Week by Week

Hourly payroll is the same sequence of calculations with one extra constraint: overtime is settled per workweek and never per pay period. Federal rules at 29 CFR 778.105 define the workweek as a fixed, regularly recurring period of 168 hours, seven consecutive 24-hour periods, and it may begin on any day and hour you pick as long as it then stays put.

That constraint bites hardest on a semimonthly schedule, where a period ends mid-week and a single workweek lands across two runs. Total the hours by workweek first, apply overtime to each week that went past forty, and only then add the weeks together for the period. Summing first and applying overtime to the total underpays people.

Rounding recorded time is permitted, with a condition attached. Federal wage and hour rules at 29 CFR 785.48 accept time computed to the nearest five minutes, tenth of an hour, or quarter hour, provided the practice averages out over time and does not consistently favor the business. A rounding rule that trims at clock-in and rounds up at clock-out fails that test however small each adjustment looks.

Federal Income Tax Withholding by Hand

Federal income tax withholding is a calculation, not a percentage. It depends on the employee's W-4, your pay frequency, and the current year's tables, and it produces a different answer for every person even when two of them earn the same amount.

Two habits make this survivable. Rebuild the calculation from the new tables every January rather than carrying last year's formulas forward, and spot-check one employee by hand against the published example each time you update, so a broken cell reference surfaces immediately instead of in October. Supplemental wages follow their own path: the flat method applies at 22 percent up to $1 million and 37 percent above that.

FICA, and the Taxes You Pay on Top

Social Security and Medicare are the easy arithmetic and the expensive surprise. You withhold 6.2 percent for Social Security on wages up to the annual wage base, which the IRS puts at $184,500 for 2026, and 1.45 percent for Medicare with no cap at all (IRS Topic No. 751). Then you match both out of the business.

Above $200,000 of wages in a calendar year you also withhold an additional 0.9 percent of Medicare tax, and the IRS is explicit that there is no employer match for it. You withhold it on wages you paid that person, without regard to filing status or a spouse's income.

Two unemployment taxes sit on top of the match, and employees never see either on a pay stub. Federal unemployment tax runs at 6.0 percent on the first $7,000 of wages paid to each employee, reduced by a credit of up to 5.4 percent when state contributions are paid on time, which brings the effective rate to 0.6 percent, or $42 a year per employee, for most employers (IRS Topic No. 759).

State unemployment tax is the variable one. Each state sets its own wage base and assigns you an experience rate that moves as claims are made against your account, so two identical businesses in neighboring states can pay very different amounts.

Depositing the Money on the Schedule You Were Assigned

You do not choose your deposit schedule. The IRS assigns it from a lookback period, the four quarters running from July 1 of the second preceding calendar year through June 30 of the preceding one (IRS Topic No. 757). Report $50,000 or less of employment tax across that window and you are a monthly depositor. Report more and you are semiweekly all of the following year.

All federal tax deposits have to travel by electronic funds transfer, so writing a check is not an option regardless of how small the amount is. That is why enrollment belongs in the six-week setup window rather than the week of your first payday.

The $100,000 rule ambushes growing businesses because it does not wait for the year to turn over. Accumulate that much liability on any single day and the deposit is due the next business day, and you are a semiweekly depositor for the rest of that year and all of the next. A single bonus run can do it.

The Quarterly and Annual Filings

Six federal deadlines a year, plus a state layer that varies. Four of the six are Form 941, and the other two land on January 31 along with everything else in your year-end.

Each base deadline shifts to the next business day when it falls on a weekend or a federal holiday, which is why copying last year's reminders forward produces at least one miss. Form 941 carries a quiet reward too: the IRS instructions let you file by the tenth day of the second month after the quarter ends if every deposit was made on time and in full (IRS).

One threshold matters more than it used to. Per the IRS, filing ten or more information returns in aggregate across all types, counting W-2s and 1099s together, means they must be filed electronically. An employer with six employees and four contractors has already crossed it, so the paper route usually is not available.

The 1099-NEC reporting threshold itself has moved. According to the IRS instructions for Forms 1099-MISC and 1099-NEC, you file for a nonemployee you paid $2,000 or more in a calendar year, for payments made on or after January 1, 2026, up from $600 previously. The figure may be adjusted for inflation beginning in 2027, and a state may still apply a lower one.

January is where doing payroll yourself feels heaviest, because year-end reconciliation, W-2s, 1099s, Form 940, and the fourth-quarter Form 941 all arrive together. Reconcile the four quarterly returns against your W-2 totals before filing anything.

What You Have to Keep, and for How Long

Two retention rules apply at the same time and they do not agree, so satisfy the longer one. The IRS asks for at least four years of employment tax records. Federal wage and hour rules ask for at least three years of payroll records and two years of the supporting material behind them.

The wage and hour side is specific. Payroll records, certificates, agreements, and employment contracts have to be preserved for at least three years (29 CFR 516.5), while time cards, wage rate tables, and the working papers behind additions to or deductions from wages carry their own two-year requirement (29 CFR 516.6). The summary outlives the raw material it was built from.

Form I-9 runs on a third clock, kept for three years after the hire date or one year after employment ends, whichever is later, and it should live separately from the personnel file so that an inspection of I-9s does not become an inspection of everything else.

Doing payroll by hand, the payroll register for each run is the document everything else reconciles against, and it needs to outlive the spreadsheet it came from. Export it, date it, and store it off the laptop you build the runs on.

What Doing It Yourself Actually Costs

Payroll software is not free and neither is doing it yourself. The difference is that one cost arrives as an invoice you can see and the other arrives as hours you do not measure plus a penalty risk you cannot price.

Start with the hours. A clean run for two or three salaried employees in one state takes fifteen to twenty minutes once the spreadsheet exists. Hourly staff add timesheet review and overtime arithmetic. A benefit deduction adds a monthly reconciliation against the insurer's invoice. Then add a deposit every month, a return every quarter, and a year-end that costs most owners the better part of a weekend.

Then price the risk rather than assuming it away. Late deposits are penalised on a sliding scale that rises with the delay, late returns separately as a percentage of unpaid tax per month, and states add their own on top. A single missed quarterly deposit can cost more than a year of software, and the calculation is uncomfortable precisely because the penalty is a probability while the fee is a certainty.

What you eventually pay for is not arithmetic, because your spreadsheet does arithmetic. You are buying tax table maintenance, deadline memory, and the year-end forms.

When Doing It Yourself Stops Being Worth It

There is a point where the arithmetic flips, and it is more predictable than it feels from the inside. Five triggers, any one of which is enough on its own, and none of which are about how confident you feel.

An employee in a second state is the sharpest. It is not an increment but a step change: a new registration, a new withholding regime, a new unemployment account and rate, new deadlines, new returns. Remote hiring means most small employers meet this earlier than planned.

Your first hourly employee is the second, because salaried-only payroll is genuinely simple while hourly payroll brings timekeeping, overtime on the regular rate, and state rules about rounding, breaks, and pay stubs. A benefit deduction or a garnishment order is the third, since both mean handling somebody else's money under rules you have to get right. The fourth is plain volume: around eight to ten employees the year-end stops being a weekend job.

The fifth is the economic test, and it is the one to apply. If a full cycle, including the deposit and the record, takes more than about half an hour of your own time a period, the fee is already cheaper than you are. Treat a single missed deadline as the trigger rather than as bad luck, because the second miss is a pattern and the pattern is expensive.

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