W-2 + 1099 side hustle? Track income and 1040-ES reserves so April isn’t a surprise

Confused about W-2 + 1099 together? Prep TY2026 records now. Plain-language IRS-cited guides plus a real Excel workbook for mixed W-2 + 1099 sole props. Not tax advice. Not a filed form. Not IRS approved.

$29 USD Not tax advice TY2026 → file 2027

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$29 USD

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Excel workbook · TY2026 · no macros · instant download. Not tax advice.

8 tabs · no macros · print for your CPA · verify on IRS.gov

By Shortell Designs · Updated October 2026

You don’t “file” quarterly estimated taxes — you PAY them

Form 1040-ES is how you pay estimated tax during the year — you do not “file” a quarterly return. See the tax season 2027 checklist: you PAY estimated tax (you don’t “file” quarters) and the 2026 Form 1040-ES quarterly due dates. Workbook only: Get the $29 Excel kit on Gumroad.

Tax season 2027 guides (IRS-cited)

Start with the tax season 2027 checklist: you PAY estimated tax (you don’t “file” quarters), then dig into due dates, who must pay estimated tax, SE / OASDI, and mileage. Dollar rates and safe-harbor tests: confirm on IRS.

Tax season 2027 checklist: you PAY estimated tax (you don’t “file” quarters)

How TY2026 prep / 2027 filing fits together for W-2 + 1099 + Form 1040-ES, with official IRS starting links.

2026 Form 1040-ES quarterly due dates

Apr 15, Jun 15, Sep 15 2026, and Jan 15 2027 — plus the early-file option. Sourced to Form 1040-ES.

Who must pay estimated tax

High-level IRS “who / who may not” notes. Thresholds and exceptions: confirm on Form 1040-ES / Pub 505.

OASDI wage base & SE tax

How Schedule SE Social Security tax shares the wage base with W-2 Box 3 wages.

2026 business mileage rates

Split-year standard mileage for business miles, with IRS notice links.

Get the $29 Excel kit on Gumroad

Eight-tab workbook: income, W-2, expenses, home office, mileage, quarterly 1040-ES reserve, annual summary.

2026 W-2 + 1099 Side-Hustle Estimated Tax Spreadsheet

A real Excel workbook for a U.S. sole proprietor who has a W-2 day job and 1099 / gig / freelance income. Not tax advice.

Track 1099 income next to your W-2 wages

Income 1099. Date, payer, form type, amount, category, year-to-date running SUM.

W-2 Wages. Employer, Box 1 wages, Box 3 Social Security wages; remaining OASDI base so SE Social Security tax is not double-counted against $184,500.

What’s in the 8 Excel tabs

Exact sheet names in W2-1099-Side-Hustle-Kit-2026.xlsx:

Tab 1 Start Here How to use, disclaimer, version 2026.1, owner profile, named 2026 constants, IRS / SSA links.
Tab 2 Income 1099 Date, payer, form type, amount, category, year-to-date running SUM.
Tab 3 W-2 Wages Employer, Box 1 wages, Box 3 Social Security wages; remaining OASDI base so SE Social Security tax is not double-counted against $184,500.
Tab 4 Schedule C Expenses Date, vendor, IRS-style category, amount, deductible formula, notes. Meals limited to 50% automatically.
Tab 5 Home Office Simplified ($5 / sq ft, max 300 sq ft) vs actual comparison. You choose one method; the selected method feeds profit.
Tab 6 Mileage Log Date, from, to, business miles, rate used (formula from the trip date), amount, purpose. Split-year rates.
Tab 7 Quarterly 1040-ES SE tax + income tax reserve estimate, remaining OASDI base, safe-harbor note, official 2026 due dates.
Tab 8 Annual Summary One screen: profit, estimated tax set-aside, mileage deduction, quarterly totals. Print for your CPA. Do not mail this file to the IRS.

Price · one-time digital download

$29 USD

Excel workbook with live formulas. Version 2026.1. No VBA, no macros. Instant download after $29 Gumroad checkout. No physical shipping. No subscriptions. Not tax advice.

Get the $29 Excel kit on Gumroad

Schedule C expenses, home office, and 2026 mileage

Schedule C Expenses. Date, vendor, IRS-style category, amount, deductible formula, notes. Meals limited to 50% automatically.

Home Office. Simplified ($5 / sq ft, max 300 sq ft) vs actual comparison. You choose one method; the selected method feeds profit.

Mileage Log. Date, from, to, business miles, rate used (formula from the trip date), amount, purpose. Split-year rates. Business standard mileage is 72.5 cents per mile from January 1 through June 30, 2026 (Notice 2026-10) and 76 cents per mile from July 1 through December 31, 2026 (Announcement 2026-11 / IRB 2026-29). Enter the trip date; the rate column is a formula.

Quarterly 1040-ES tax reserve (not a filed form)

SE tax + income tax reserve estimate, remaining OASDI base, safe-harbor note, official 2026 due dates.

The Quarterly 1040-ES tab is an estimate of federal self-employment tax and income-tax reserve. It is not a filed IRS form. Verify every constant against current IRS and SSA pages before you pay or file. Pay estimates via IRS Direct Pay or EFTPS, not through this page.

Calendar-year due dates from Form 1040-ES (2026): April 15, 2026; June 15, 2026; September 15, 2026; January 15, 2027. You do not have to make the January 15, 2027 payment if you file the 2026 return by February 1, 2027 and pay the entire balance with the return.

Withholding or quarterly payments? How a W-2 + 1099 household can pay as it goes

Federal income tax is pay-as-you-go: you pay during the year through withholding, estimated payments, or both (IRS Topic No. 306). With a day job and a side business, you have more than one way to cover the side income. Here are the options the IRS describes:

Ways to cover tax on 1099 income when you also have W-2 wages
Option	How it works	What the IRS says
More withholding at the day job	File a new Form W-4 with your employer and enter an extra amount to withhold	You may be able to avoid estimated payments on other income this way. Form W-4 has a line for the extra amount (Form 1040-ES 2026; Estimated taxes)
Quarterly Form 1040-ES payments	Pay through Direct Pay, EFTPS, your Online Account, card, or check with a voucher	Four 2026 due dates. You can also pay the full amount by April 15, 2026 (Form 1040-ES 2026)
Apply last year’s overpayment	Credit part or all of a 2025 refund to 2026 estimated tax	Listed as a payment option in Pub. 505 (2026)
A mix of the above	Withholding covers part, estimates cover the rest	Estimated payments aren’t required if withholding in each payment period is at least one-fourth of your required annual payment, or if you’ll owe under $1,000 with your return (Pub. 505 (2026), “Estimated Tax Payments Not Required”)

The IRS Tax Withholding Estimator can help you decide whether to change your W-4. The workbook’s quarterly tab is a place to write down your own reserve estimate next to these choices. It doesn’t make the choice for you.

2026 IRS figures used in this kit

OASDI / Social Security wage base: $184,500
Mileage Jan 1 – Jun 30, 2026: 72.5 cents / mile
Mileage Jul 1 – Dec 31, 2026: 76 cents / mile
SE net-earnings factor: 92.35%
SE Social Security / Medicare: 12.4% + 2.9%
Simplified home office: $5 / sq ft, max 300 sq ft
1040-ES due dates: Apr 15, Jun 15, Sep 15, 2026; Jan 15, 2027
Meals limitation: 50% (general rule)

Constants live as named cells on Start Here. If IRS or SSA later revises a figure, change the matching parameter cell; dependent formulas update. Sources are listed below. Standard deductions used: Single / MFS $16,100; MFJ / QSS $32,200; Head of household $24,150 (IR-2025-103; Form 1040-ES 2026).

Self-employment tax: when it starts and one deduction people miss

Per the IRS, you must pay self-employment tax and file Schedule SE if your net earnings from self-employment were $400 or more. (Church employee income has its own, separate threshold.) Net earnings from a sole proprietorship or independent contracting are generally subject to SE tax (IRS — Self-employment tax).

The same IRS page notes that you can deduct the employer-equivalent portion of your SE tax when you figure adjusted gross income. W-2 employees can’t deduct the Social Security and Medicare taxes withheld from their wages. When you estimate a side-hustle reserve, use the Form 1040-ES worksheet, which includes this deduction. Don’t just apply one flat percentage to profit (Form 1040-ES 2026 worksheet; Pub. 505 (2026), Worksheet 2-3).

How you use the $29 workbook

Open in Microsoft Excel (Excel 2016 or later; Microsoft 365 preferred). Enable editing if Protected View appears.
Yellow cells with blue font are inputs. White cells are formulas. Do not type over formulas.
Confirm filing status on Start Here. Overwrite sample rows with your 2026 records before relying on totals.
Work the sheets in order: income → W-2 → expenses → home office → mileage → quarterly reserve → annual summary.
Formulas use standard functions (SUM, SUMIF, IF, ROUND). No VBA, no macros.

What this kit does not do

State income tax (optional dollar reserve you type); QBI wage / UBIA / specified-service phaseout math (warning only); capital-gain rates; NIIT; AMT; SE health insurance; retirement contribution deductions; most credits; dependents; depreciation schedules; inventory; employees/payroll beyond a W-2 you already received; annualized income installments; farming/fishing 66⅔% estimated-tax rule. It does not file Form 8829, Schedule C, Schedule SE, or Form 1040-ES for you.

Year-end records checklist for a W-2 + 1099 side hustle

Gather these before you fill in any worksheet, whether it’s ours, a tax program’s, or a preparer’s. The IRS notes that business purchases and sales generate supporting documents, and that you must keep records as long as needed to prove the income or deductions on a return (IRS — Recordkeeping).

Every Form W-2 for 2026, plus your last pay stub for a year-to-date check of wages and withholding
Each 1099 you receive (for example 1099-NEC, 1099-K, or 1099-MISC), along with your own income log. Not every payment arrives with a form
Receipts and invoices for business expenses, grouped the way Schedule C groups them (About Schedule C)
A mileage log or trip sheets with a written business purpose. Pub. 463 counts a log kept weekly as a timely record (Pub. 463)
Square footage of the space used regularly and exclusively for business. The simplified option uses that area, up to 300 sq ft, and the regular method uses the percentage of your home (IRS — Simplified home office option)
Date, amount, and confirmation number for every 2026 estimated payment, including any 2025 overpayment you applied
Your 2025 return. Form 1040-ES uses it as the starting point for 2026 estimates and for the prior-year safe harbor (Form 1040-ES 2026)

How long to keep them: the IRS says 3 years in many cases, with longer periods in specific situations. For example, it’s 6 years if you leave out income worth more than 25% of the gross income shown on your return (IRS — How long should I keep records?).

FAQ

Does it need Excel macros?

No. The workbook is live formulas only — no VBA, no macros. Works in Microsoft Excel. Sample rows ship so you can inspect formulas, including the July 1 mileage-rate switch.

Which cells do I type in?

What mileage rates does 2026 use?

Split year. Business standard mileage is 72.5 cents per mile from January 1 through June 30, 2026 (Notice 2026-10) and 76 cents per mile from July 1 through December 31, 2026 (Announcement 2026-11 / IRB 2026-29). Enter the trip date; the rate column is a formula.

What is the 2026 OASDI wage base in this kit?

$184,500, from the SSA contribution and benefit base and Form 1040-ES (2026). Self-employment Social Security tax (12.4%) shares that annual base with your day-job Box 3 Social Security wages. Remaining base (not below zero) is the maximum side-hustle earnings still subject to the 12.4% SE Social Security tax. Medicare (2.9%) has no wage-base cap.

Does it calculate state tax or full QBI phaseout?

No. State income tax is not calculated — you may type an optional state reserve. QBI is a simplified 20% estimate (with a $400 floor if active QBI ≥ $1,000, capped at 20% of taxable income before QBI). Wage / UBIA / specified-service limits on Form 8995-A are not applied; a warning appears if taxable income is above the 2026 Form 8995-A draft thresholds.

Is this tax advice or a filed IRS form?

Neither. Shortell Designs is not a CPA. The Quarterly 1040-ES tab is an estimate of federal self-employment tax and income-tax reserve. Verify every constant against current IRS and SSA pages before you pay or file. Pay estimates via IRS Direct Pay or EFTPS, not through this page.

When are 2026 estimated-tax payments due?

What is included in the $29 download?

One Excel workbook for tax year 2026, eight tabs listed above, plus a how-to with IRS / SSA links inside the paid kit. This public page is the sales listing only. The workbook is not hosted here and is not a free download.

Can I raise my W-4 withholding instead of making quarterly payments?

Often, yes. Form 1040-ES (2026) says wage earners may be able to avoid estimated payments on other income by filing a new Form W-4 to have more tax withheld. The IRS Tax Withholding Estimator can help you choose an amount (Form 1040-ES 2026; Tax Withholding Estimator).

My side income started in the fall. Did I miss the deadlines?

Not necessarily. Pub. 505 (2026) Table 2-1 says that if you first have income subject to estimated tax after August 31, your first payment is due January 15 of the next year. See the 2026 estimated tax dates guide for the full table (Pub. 505 (2026)).

Does paying the safe-harbor amount mean I won’t owe in April?

No. The IRS says you may still owe tax when you file even if you pay the required annual payment. The safe harbor is about the underpayment penalty, not your final balance (Form 1040-ES 2026). Not tax advice. Consult a tax professional or IRS resources for your situation.

IRS / SSA sources

Figures in the kit were compiled from these official pages. Always re-check before you pay or file. No affiliates.

Disclaimer (not tax advice)

Not tax advice. This workbook is a bookkeeping log and an estimate of federal self-employment tax and income-tax reserve. It is not a substitute for IRS forms, IRS publications, or a CPA / enrolled agent who knows your facts. Shortell Designs is compiling this kit — not a CPA, not a tax preparer, and not offering a professional tax service.

Estimates only. Verify every constant against current IRS and SSA pages before you pay estimated tax or file a return. Safe-harbor notes do not guarantee you will owe nothing at filing. Home-office exclusive-use is a legal test you attest by using the sheet (Publication 587). QBI phaseout, state tax, and several other items are intentionally not fully modeled.

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