Tax Planning Basics

The single most misunderstood idea in taxes: your marginal tax rate is the rate on your next dollar, not on all your dollars. The U.S. uses tax brackets — income is taxed in slices, with each slice taxed at a higher rate. A single filer might pay 10% on the first slice, 12% on the next, 22% on the next, and so on.

Run the numbers. If the 22% bracket starts at $48,000 and you earn $50,000, only the top $2,000 is taxed at 22% — the first $48,000 is taxed at the lower rates. Your effective rate — total tax divided by total income — is always lower than your marginal rate. This is why "a raise pushed me into a higher bracket so I take home less" is a myth: only the dollars above the line get the higher rate.

This matters for planning because every tax decision is a marginal decision. A deduction saves you tax at your marginal rate. A Roth vs. Traditional choice (LP-102) is a bet on your marginal rate now vs. your marginal rate in retirement. Learn your marginal rate and half of tax planning clicks into place.

A deduction reduces the income that gets taxed. A credit reduces the tax itself, dollar for dollar. Credits are worth more: a $1,000 deduction in the 22% bracket saves you $220; a $1,000 credit saves you $1,000.

Most people take the standard deduction — a flat amount the IRS lets everyone subtract (tens of thousands for joint filers, adjusted yearly). You only itemize — listing mortgage interest, state taxes, charitable gifts, and the like — if your total exceeds the standard deduction. For most filers, the standard deduction wins, which means smaller itemizable expenses do not actually save tax.

The planning move: bunching. If your itemizable expenses are near the threshold, bunch two years of charitable gifts or medical expenses into one year — itemize that year, take the standard deduction the next. Same spending, more tax saved.

When you sell an investment for more than you paid, the profit is a capital gain. Hold the investment more than a year and it is a long-term gain — taxed at preferential rates (0%, 15%, or 20% depending on income), far below ordinary income rates. Sell within a year and it is a short-term gain — taxed as ordinary income, like wages.

This is why patience is taxed less than impatience. A trader flipping stocks every few months pays ordinary rates on every gain; a buy-and-hold investor pays the lower long-term rates. The one-year line is one of the most valuable lines in the tax code.

Two companion ideas. Tax-loss harvesting is selling losers to offset winners — realized losses cancel realized gains, and up to $3,000 a year can offset ordinary income. And wash-sale rules forbid claiming the loss if you buy the same investment back within 30 days. Harvest in December, but respect the 30-day window.

Asset location is the idea that different accounts should hold different investments. Put tax-inefficient assets — bonds, REITs, anything throwing off ordinary income — inside tax-advantaged accounts (401(k), IRA), where the tax drag disappears. Put tax-efficient assets — stock index funds you rarely sell — in taxable accounts, where long-term gains get the preferential rate anyway.

The hierarchy from LP-102 already does most of this automatically: max the match, fund the IRA, fund the HSA, then the taxable account. But within those accounts, the placement matters too. A bond fund in a taxable account bleeds taxes every year; the same fund in a Traditional IRA compounds untouched. Same investment, different account, different outcome.

The final habit is the least glamorous and the most valuable: keep records. Every tax move in this lesson — deductions, credits, harvested losses, HSA receipts (LP-102), charitable gifts — only works if you can prove it. The IRS does not accept "I think I donated that."

The system can be simple: one folder (physical or digital) per tax year, with subfolders for income documents, deductions, and investment records. Save every 1099, every donation receipt, every HSA medical receipt. Keep tax returns and supporting documents at least three years — seven if you underreported income by a lot, which you will not, because you keep records.

Good records also make professional help cheaper. If you ever hire a CPA, organized records cut their hours — and their bill. The boring superpower compounds just like money does.

Taxes close out the core Retirement and Long-Term Planning school. LP-108 "Estate Planning Basics" continues the school with beneficiaries, wills, trusts, and the legacy checklist — making sure everything you built goes where you intend.