米国の自営業税を計算する方法

Independent contractors, sole proprietors, and many partners can owe self-employment tax on net earnings from their trade or business. A client normally pays the invoice without taking Social Security or Medicare tax out first. The person doing the work reports business profit and calculates the federal obligation on a tax return.

The label 1099 is a clue about how a payment was reported, but the form alone does not determine the calculation. Schedule C or another business schedule usually establishes income and deductible business expenses. Schedule SE then uses the resulting net earnings, subject to its filing threshold, exceptions, and optional methods.

Employee wages follow payroll rules instead. Business structure and tax treatment can make an owner's payment something other than self-employment income. When classification is unclear, settle that question before trying to estimate the tax.

Start with annual net business profit, not the total of every client deposit. For a simple illustration, suppose net profit after ordinary business expenses is $40,000. Schedule SE applies its 92.35% factor. The estimated self-employment earnings base is $36,940.

Next, apply the two parts of the estimated federal rate. The estimated Social Security part is $4,580.56 at 12.4%, and the estimated Medicare part is $1,071.26 at 2.9%. Add them for an estimated self-employment tax of $5,651.82. One-half of that estimated tax, $2,825.91, is the related income adjustment in this simplified example.

This worked estimate assumes no employee wages competing for the Social Security limit and no additional Medicare calculation. The filed amount can change when those facts apply, when the business profit changes, or when a special Schedule SE method is used. Run the actual year's form with the full return rather than treating $5,651.82 as a quote.

The estimated 15.3% federal rate applies within an annual calculation. Schedule SE starts from net earnings rather than blindly multiplying each invoice. It also coordinates the Social Security portion with wages and applies rules that a single payment record does not know.

Nothing in that calculation turns a client into a payroll department. A contractor might receive the full invoiced amount and later make estimated payments. Setting money aside can be sensible cash planning, but a private set-aside is not withholding and should not be described as tax already paid.

Income tax is separate from self-employment tax. A person can owe both, and credits or other income can change the full return. The $5,651.82 figure in the example estimates only self-employment tax under the stated facts. It does not estimate the person's complete federal or state bill.

Federal income tax is pay as you go. Someone whose income has little or no withholding may need to make estimated payments during the year. Those payments can cover expected income tax and self-employment tax together; they are not a separate quarterly version of Schedule SE.

For calendar-year 2026, IRS Publication 505 lists payment dates of April 15, June 15, September 15, and January 15, 2027. A weekend or legal holiday can move a deadline, and special rules apply in some situations. Use the current publication or Form 1040-ES before sending a payment.

Equal installments fit income that arrives fairly evenly. A contractor with seasonal or uneven earnings may need the annualized income installment method instead. Publication 505 also explains when estimated payments are generally required and how prior-year tax can affect the required annual payment.

The 1099 preview labels the row Est. self-employment tax (15.3%). It is an estimate for reference. Nothing is withheld from the contractor's payment, and the document does not report a tax deposit to the IRS.

The record uses the entered Gross amount to produce a period-level planning figure. Schedule SE uses annual net earnings after the relevant business calculation. That difference is why the payment record carries an estimate label and why its figure should not be transferred to a filed return.

Net pay on the preview is the gross amount minus the displayed estimate. Read it as money remaining after a planning set-aside. If the client sent the full gross payment, the bank deposit can be higher than that displayed remainder because the client withheld nothing.

The PDF remains a self-prepared payment record. It is not employer-issued, it does not file Schedule SE, and it does not prove that an estimated payment was made. Keep the tax calculation and proof of any IRS payment in the tax records where they belong.

Keep the invoices and Forms 1099 that document receipts, then keep the receipts or ledger entries for business expenses. Together they support the net profit used in the Schedule SE calculation. A bank statement can confirm cash movement but does not classify every deposit or expense by itself.

Save the completed tax return, Schedule C or other business schedule, and Schedule SE with the working papers behind the estimate. Keep confirmation of estimated payments separately. A payment record can help organize one period, but it cannot replace this annual trail.

If you share a payment record for an income review, pair it with the tax return and bank statements the recipient asks for. Acceptance is not guaranteed. Keep the file internally consistent, and label earned income, planning estimates, and payments sent for what they are.