Did it go up 2% or 2 points? Percentage points vs. percent
Tell a change in percentage points from a change in percent, and calculate both for each branch's repeat purchase rate.
Free course. Your Maestro, an AI, .
La Ceiba has a loyalty card. Every year it tracks its repeat purchase rate: of the cardholders who bought something, what percentage bought again within 90 days. In 2024 it was 37.7%, and in 2025 it was 39.0%.
The sales director asks you for one sentence for the annual report. How much did it go up?
Check yourself: The chain's repeat purchase rate went from 37.7% to 39.0%. Which statement is correct?
Two ways to measure a change in a percentage
When the thing that changes is already a percentage, there are two correct numbers, and they say different things:
| The calculation | With the repeat purchase rate | |
|---|---|---|
| Percentage points | new − previous | 39.0 − 37.7 = 1.3 points |
| Percent (relative change) | (new − previous) ÷ previous × 100 | 1.3 ÷ 37.7 × 100 = 3.4% |
The points are the distance between the two percentages: how far the needle moved. The percent is the previous page all over again: the change compared with where you started, and the base is 37.7.
If you write "the repeat purchase rate rose 1.3%," readers will take it to mean it went from 37.7% to 38.2% (37.7 × 1.013). It's a small error in the number and a big one in trust: the day someone notices, they'll doubt your whole report.
Why the base matters so much
The same one-point increase can be a huge change or a tiny one, depending on where you start. Here's how much "one more point" is from four different starting points:
That's why people pick whichever number suits them. If you want a change to sound big, you quote the percent when the base is small ("billing errors up 50%!", from 2% to 3%). If you want it to sound small, you quote the points when the base is large. Neither number is false; each one hides the other half.
The rule for your reports: say from what to what, then give the change in points. Add the percent only if it helps, and spell out which one it is:
The repeat purchase rate rose 1.3 points, from 37.7% to 39.0%.
Billing errors went from 2% to 3% of invoices: one point more, which is 50% more than last year.
With both levels on the page, nobody has to guess.
If you report rates, margins or market shares at work, ask your Maestro how to write the change in one of them.
Try it
The query below calculates each branch's repeat purchase rate for both years and the difference in points. First it builds a helper table called tasas with two columns, r24 and r25: the rate for each year. Then it shows the rounded columns.
Your job is to add the cambio_pct column, the change in percent. The line that starts with -- has the recipe: the difference, divided by the 2024 rate, times 100. Delete the two dashes, add a comma at the end of the puntos line and write the calculation inside ROUND(..., 1).
If the query throws an error after you delete the dashes, ask your Maestro what's missing.
Add a cambiopct column after puntos, with the percent change in the repeat purchase rate, rounded to one decimal place: ROUND((r25 - r24) / r24 100, 1) AS cambiopct. Keep the same order. You're done when Ceiba Express is at the top with 3.8 points and 15.4%, and Centro shows 1.0
Your turn
Add a cambio_pct column after puntos, with the percent change in the repeat purchase rate, rounded to one decimal place: ROUND((r25 - r24) / r24 * 100, 1) AS cambio_pct. Keep the same order. You're done when Ceiba Express is at the top with 3.8 points and 15.4%, and Centro shows 1.0 points and 3.5%.
Tables: sucursales (sucursal, municipio, ventas_2024, ventas_2025, clientes_2024, recompraron_2024, clientes_2025, recompraron_2025)
sucursales · 24 rows
| Column | Type |
|---|---|
| sucursal Nombre de la sucursal. | VARCHAR |
| municipio Municipio (ficticio) donde está. | VARCHAR |
| ventas_2024 Ventas del año 2024, en pesos. | BIGINT |
| ventas_2025 Ventas del año 2025, en pesos. | BIGINT |
| clientes_2024 Clientes con tarjeta que compraron en 2024. | BIGINT |
| recompraron_2024 De esos clientes, cuántos volvieron a comprar en menos de 90 días (2024). | BIGINT |
| clientes_2025 Clientes con tarjeta que compraron en 2025. | BIGINT |
| recompraron_2025 De esos clientes, cuántos volvieron a comprar en menos de 90 días (2025). | BIGINT |
First rows
| sucursal | municipio | ventas_2024 | ventas_2025 | clientes_2024 | recompraron_2024 | clientes_2025 | recompraron_2025 |
|---|---|---|---|---|---|---|---|
| Centro | Ciudad Ceiba | 41200000 | 43800000 | 9800 | 2840 | 10400 | 3120 |
| Chapultepec | Ciudad Ceiba | 27900000 | 26100000 | 7100 | 2200 | 6900 | 2140 |
| Plaza Norte | Ciudad Ceiba | 9400000 | 10100000 | 2600 | 960 | 2750 | 1070 |
Every run starts from fresh copies of the course's tables, so try anything. Tab indents; to leave the editor, press Escape, then Tab.
Ready to run your query.
Take your time with the table. Centro rose one point, from 29.0% to 30.0%, and that's 3.5% more. Ceiba Express rose 3.8 points, which is 15.4% more, because it started at 25%. The small branches, which already had rates near 60%, rose between one and three points, and in percent that's 6% or less: on a high base, one point doesn't weigh much.
If someone tells you "Ceiba Express's repeat purchase rate rose 15%," now you know what to ask: 15% or 15 points? They're very different stories: one means going from 25% to 28.8%, the other from 25% to 40%.
One last question, about a number many offices check every month.