How to make a Sankey diagram of your debt payoff.

The year we start from

Three loans, as the year-end statements print them: what each balance was on the first of January, what the year's payments and interest added up to, and what is owed now.

The seven steps

1. 1

   Start from the statements you already have

   Each loan's year-end statement, or the loan page in your banking app, carries everything the diagram needs: the balance you started the year with, what you paid in, the interest charged, and what is left. Nothing else. No spreadsheet, no tracking app, no account anywhere.

   One calendar year is the right window. It is long enough for the shape of the payoff to show, and it matches the statements you will be handed anyway.

2. 2

   Give every loan a name you would say out loud

   The loan names become the columns of the diagram. Credit card, car loan, student loan — not the issuer's product code. If you are paying down five cards, name the one you are killing first by what it is: the department store card, the old card.

   Three to six loans keep every ribbon readable. Group the small ones into one node if you have more.

3. 3

   Flow the starting balances in

   One line per loan: the source, the amount, the loan. Starting debt, amount, loan name. These three lines are the left edge of the diagram — the debt as it stood on day one.

   Use one shared source, starting debt, so the three loans are comparable from the first pixel. Separate sources would draw three disconnected pictures.

4. 4

   Let interest arrive on top

   Here is the step that makes a payoff diagram honest. Over the year, each loan accrues interest, so more money goes through the loan than the starting balance alone. Draw it: interest accrued, the amount, the loan.

   That single extra stage on the left is what turns the interest bill from a footnote into a ribbon. The wider the interest-accrued ribbons sit against the principal-paid ones, the more of your year went to the lender.

5. 5

   Flow the year out, and let a paid-off loan end

   Every dollar that entered a loan leaves it three ways: principal paid, interest paid, or remaining balance. One line each. The statements split principal and interest for you; the remaining balance is the starting balance minus the principal paid.

   A loan you killed has no remaining balance line at all — the credit card in the example ends at principal and interest, and the missing node is the whole point of the picture.

   The year, as flow lines

   • Starting debt [$3,800] Credit card
   • Starting debt [$7,400] Car loan
   • Starting debt [$12,300] Student loan
   • Interest accrued [$810] Credit card
   • Interest accrued [$620] Car loan
   • Interest accrued [$860] Student loan
   • Credit card [$3,800] Principal paid
   • Credit card [$810] Interest paid
   • Car loan [$2,600] Principal paid
   • Car loan [$620] Interest paid
   • Car loan [$4,800] Remaining balance
   • Student loan [$1,900] Principal paid
   • Student loan [$860] Interest paid
   • Student loan [$10,400] Remaining balance
6. 6

   Snowball or avalanche — the diagram does not judge

   Snowball pays the smallest balance first; avalanche pays the highest rate first. In the worked example the credit card is both, so the two strategies agree and the diagram is the same either way.

   When they disagree, draw the year twice, once per ordering. The interest-accrued ribbons answer the argument better than any forum thread: the ordering that thins those ribbons fastest is the one that costs you less.

7. 7

   Export, and next year paste the new balances

   Theme, ribbon curve and export size are controls beside the canvas, and each redraws the diagram as you move it. Square suits the image post; deck size, 1600 by 900, suits a document.

   A watermarked PNG download is free, with no account. Clean PNG and SVG come with a Pass. Next January, replace the amounts in the same lines and the two years compare honestly.

What those lines draw

Nothing was retyped for this picture. It is the 14 lines above, drawn at square size, which suits the image post this diagram is usually made for.

Read it once with the interest in mind: $2,290 of the year went to interest, and the smallest balance — the card — is the only node with no remaining-balance line.

The same year, with one extra $190 a month

This is the argument the diagram settles best. The same three loans, the same year, with $2,280 more paid in across the twelve months.

The interest ribbon thins from $2,290 to $2,170, and the debt carried into next January drops from $15,200 to $12,800 — the car from $4,800 to $2,800, the student loan from $10,400 to $10,000. Same loans, same rates — the acceleration does the work.

Paying debt down is one half of the same picture — the other half is where the paycheque goes. That diagram is in how to make a Sankey diagram of your take-home pay.

Where it goes wrong

• Drawing the payments, not the balances

  A diagram whose source is this month's $800 payment shows the instalment, not the debt. Start from the starting balances — the payment is what the middle of the diagram spends, not what it is about.

• One line per payment

  Twelve months across three loans is 36 hairline ribbons. The statements already sum the year; so should the lines. One line per loan, per destination.

• Leaving interest out

  Without the interest-accrued stage, the loan nodes pay out more than they took in and the arithmetic visibly does not close. Worse, the diagram stops being able to show the thing a payoff is a fight against.

• Forgetting the remaining balance

  The balance that is left is a destination like any other. Omit it and the diagram implies the year's payments erased the debt, which flatters nobody by next January.

Questions

How do I make a Sankey diagram of my debt payoff?

Flow each loan's starting balance from one shared source into the loan, add an interest-accrued line per loan, then flow out principal paid, interest paid and remaining balance per loan. Paste the lines into the studio — the template opens with a year already drawn.

Where do I get the principal and interest split?

Your statements make it. Every year-end loan statement, and most loan portals, report interest paid for the year; the principal paid is the rest of what you paid. The remaining balance is the starting balance minus the principal paid.

Why does interest flow into the loan instead of out of it?

Because the loan costs more than its starting balance over the year. Drawing interest as an input keeps every loan node balanced and puts the interest bill on the diagram as a ribbon instead of in a footnote.

Can the diagram show snowball versus avalanche?

Yes, by drawing the year twice, once per payoff ordering. The difference shows up in the interest-accrued ribbons and in which loans still have remaining-balance nodes at the end of the year.

Can I use this for a mortgage?

You can, but a mortgage year is almost all interest and one hairline of principal, which is a true and rather demoralising picture. It works best alongside the other loans, where the contrast is the message.

What does it cost?

Building, styling and a watermarked PNG are free, with no account. A Pass is $12 for a week, $39 for a quarter or $99 for a year, paid once, and buys saving, re-running and clean PNG or SVG export.

Other starting points

• Debt payoff Sankey templateBalances in, interest on top, and the year out as principal, interest and what is left.
• Sankey diagram of your take-home payOne payslip, one month of transactions, the buckets they group into.
• Personal budget Sankey templateTake-home pay split into rent, living costs, savings and investments.
• Sankey diagram from Excel dataCopying a range straight into the flows, without retyping a thing.

Passes are paid once: $12 for a week, $39 for a quarter, $99 for a year. A Pass buys saving, re-running, saved themes and clean PNG or SVG export.