Learning tool · T1 personal tax

How a tax return actually works.

A line-by-line walk-through of a Canadian T1 summary — structured the way your accountant formats it, with stacked bars showing how each section breaks down.

Sample T1 summary · 2026 tax year Single BC taxpayer · anonymized example

Why the math works the way it does

How marginal tax brackets work

Canadian tax isn't a flat percentage of income. Each bracket of income above a threshold is taxed at a higher rate — but only the dollars inside that bracket pay the higher rate.

So someone with $123,000 of taxable income doesn't pay 38% on all of it. They pay 19.6% on the first $50,363, 21.7% on the next slice, 28.2% on the next, and only hit 38.3% on the dollars above $117,045.

This taxpayer is in the 38.3% bracket. Every extra dollar earned would be taxed at this rate — which is why RRSP contributions are so valuable here. A $1,000 RRSP contribution saves ~$383 in tax for someone in this bracket.

The table on the right shows the combined federal + BC marginal rate on ordinary employment / interest income for 2026.

Taxable income	Federal	BC	Combined

Rows marked with a chevron expand — click to see the RRSP planning angle for that boundary.

Combined federal + BC marginal rates for ordinary income, 2026. Eligible dividends and capital gains are taxed at lower combined rates (not shown). Source: taxtips.ca.

Where RRSPs deliver the most value

The two highlighted boundaries above are among the steepest jumps in BC's marginal-rate schedule — crossing them adds 5 to 6.5 percentage points in tax on the next dollar earned. They're also the boundaries where an RRSP contribution does the most work.

Because RRSP contributions reduce taxable income dollar-for-dollar, a contribution that drops you below one of these thresholds saves tax at the higher rate — right up until you cross the line.

$58,523 boundary (21.7% → 28.2%): a dollar above pays 28.2¢ in tax; a dollar below pays 21.7¢. An RRSP dollar that crosses the threshold saves the full 6.5pp difference.
$117,045 boundary (32.8% → 38.3%): this is where our sample taxpayer lives. A $1,000 RRSP contribution saves $383. Contributing the full $5,955 above the threshold drops taxable income to exactly $117,045 — the highest-yield contribution at this rate. Beyond that, the rate steps down to 32.8%.

The takeaway: when RRSP room is limited, prioritize using it to clear these big jumps. When it's plentiful, contributions still help — just at progressively lower rates as you step down through the brackets.

For learning only. This tool uses generic round numbers for illustration. Actual tax credits phase out at certain income levels, brackets are indexed each year, and BC has its own credit calculations that affect the provincial-tax line. Numbers shown are illustrative and won't match your specific situation. For advice on your own return, please book a chat.

Plain-English glossary

The terms most people get tripped up on, in one place.

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