What it means
The calculation starts with gross income, which is broader than most people assume. It includes wages, self employment profit, interest, dividends, rental income, capital gains, taxable retirement withdrawals and various other receipts, all added together before anything is taken off.
This total is what the tax system treats as your starting position. From that total you subtract a defined set of adjustments, often called above the line deductions because they appear above the AGI line on the return.
Typical items include deductible retirement contributions, the deductible portion of self employment tax, self employed health insurance premiums, health savings account contributions and student loan interest. The list is fixed by law, so you cannot subtract ordinary living costs or business expenses that belong elsewhere on the return.
The reason AGI matters more than its position on the form suggests is that dozens of other rules key off it. Eligibility for particular tax credits, the deduction limit on charitable giving, the threshold for medical expense deductions and the ability to contribute to certain retirement accounts are all tested against AGI or a close variant.
A few thousand dollars either side of a threshold can therefore be worth far more than the tax on that income alone. For a business owner the number is doubly important because it links personal and business planning.
A contribution to a retirement plan reduces AGI as well as providing for the future, and timing an invoice or a deductible expense across a year end can move AGI enough to preserve a relief. This is legitimate planning, not avoidance, provided the underlying transactions are genuine.
One point of confusion is worth clearing up early. AGI is not the same as taxable income, which is what you get after subtracting either the standard deduction or itemised deductions, and it is not the same as modified adjusted gross income, which adds certain items back for specific tests.
Anyone quoting an AGI threshold should be asked which of the three they actually mean.
In practice
Real-world examples.
Example
A software engineer earning $138,000 discovers that a particular education credit phases out just above his AGI. Increasing his pre tax retirement contribution by $6,000 pulls his AGI below the threshold and preserves a credit worth more than the deferred tax on the contribution.
Example
A couple applying for a mortgage are asked for their AGI rather than their gross salary, because the lender wants the figure the tax return actually reports. Their large deductible retirement contributions make their AGI noticeably lower than their combined pay, which affects the size of loan offered.
Example
A freelance photographer with $86,000 of business profit deducts her self employed health insurance and half of her self employment tax as above the line adjustments. Her AGI lands low enough that a portion of her medical expenses clears the deduction threshold, which is calculated as a percentage of AGI.
Think of it
“AGI is the abbreviation for Adjusted Gross Income-important tax figure.
Formula
Calculation
Adjusted gross income = total gross income - allowable above the line adjustments
Consider a marketing consultant who earns a $95,000 salary from an employer, makes $18,000 of profit from freelance work, and receives $2,000 of bank interest. Total gross income = $95,000 + $18,000 + $2,000 = $115,000.
Her allowable adjustments for the year are a $7,000 deductible retirement contribution, $3,000 of self employed health insurance premiums and $1,000 of student loan interest, giving $7,000 + $3,000 + $1,000 = $11,000 of adjustments. Adjusted gross income = $115,000 - $11,000 = $104,000.
That $104,000 is the figure her accountant will test against every threshold on the return, and it is also the number a lender or a college financial aid office will ask for. Her taxable income will be lower again once the standard deduction is applied.Case study
Seen in the real world.
The following is an illustrative and entirely fictional example. Delaney Craft Interiors, an invented two person design studio operating as a partnership, had a strong year with each partner reporting around $148,000 of profit. Neither partner had ever looked past the bottom line of their tax return, and both assumed that tax planning meant finding more expenses to claim.
Their fictional accountant took a different approach and modelled the effect of AGI thresholds. By establishing a solo retirement plan and contributing $24,000 each before the filing deadline, both partners moved below the level at which two separate reliefs began to phase out. The combined effect was roughly $9,600 of tax saved between them, on money that stayed in their own retirement accounts rather than leaving the business.
The wider lesson in this illustrative story was about sequencing. The partners had been making retirement contributions in whatever month suited their cash flow, with no reference to where the contributions left their AGI. Once the accountant tied contribution planning to a projected AGI figure each November, the same cash produced a measurably better result.
Watch out
Common mistakes.
- Using gross salary when a form asks for AGI, which overstates income and can cost eligibility for reliefs the taxpayer actually qualifies for.
- Confusing AGI with taxable income, and therefore expecting the standard deduction to have already been taken off.
- Assuming any business or personal expense can reduce AGI, when only the specific statutory list of adjustments applies above the line.
Questions
People also ask.
Where do I find my AGI from last year?
It appears on a designated line of your filed tax return, and tax software and the tax authority's online account both display it, often because it is needed to verify an electronic filing.
Does a higher AGI always mean more tax?
Not directly, since tax is charged on taxable income, but a higher AGI can push you past thresholds that remove credits and deductions, so the effective cost of extra income can be steeper than the headline rate.
What is modified adjusted gross income?
It is AGI with certain deductions and excluded income added back, and different rules define it slightly differently, so it is always worth confirming which version a particular test uses.
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