Sort CSV Files Online
Sort CSV files by any column, ascending or descending, directly in your browser.
How to sort CSV files
- Drop your file onto the upload area. It is loaded into the in-browser engine and the first 200 rows are shown.
- Choose the first column in the Sort by row and set it to Ascending or Descending.
- Click + Add sort key to add a Then by row for breaking ties. You can use up to four keys, and ✕ removes one.
- Click Sort. The preview shows the first 200 rows in their new order.
- Click Download to save the sorted file in the same format you uploaded.
Your file is processed locally in your browser and is never uploaded. The free limit is 50 MB per file; larger files work if your device has the memory for them.
Worked example
A teacher has exam results for two classes and wants each class grouped together, with the highest score at the top of each group. One student has no score yet.
Input (CSV)
student,class,score,submitted
Priya,B,88,2026-05-12
Tom,A,72,2026-05-11
Lena,A,91,2026-05-12
Omar,B,,2026-05-13
Jae,A,85,2026-05-10Settings
- Sort by: class, Ascending
- Then by: score, Descending
Result
| student | class | score | submitted |
|---|---|---|---|
| Lena | A | 91 | 2026-05-12 |
| Jae | A | 85 | 2026-05-10 |
| Tom | A | 72 | 2026-05-11 |
| Priya | B | 88 | 2026-05-12 |
| Omar | B | NULL | 2026-05-13 |
Rows are first ordered by class, so all of class A comes before class B. Inside each class, the second key orders scores from high to low. Omar has no score, and empty values always go last, whether the direction is ascending or descending. That is why he stays at the bottom of class B.
Working with CSV files
Sort order depends on the type each CSV column gets when the file is loaded. A column of whole numbers sorts numerically, so 9 comes before 10. A column that mixes numbers with text such as "n/a" loads as text and sorts character by character, which puts "10" before "9". ISO dates like 2026-05-12 are detected and sort by date. Codes with leading zeros, such as 00501, stay as text and keep their zeros. Times without a date, such as 09:30, are detected as a time type and sort by clock time.
Text sorting is case-sensitive and uses character codes, so all capitalised values come before lowercase ones: "Zeta" sorts ahead of "apple". Run Convert Case first if that matters. Blank cells load as NULL and end up at the bottom in both directions. The downloaded CSV keeps the header row and comma delimiter, and fields containing commas, quotes or line breaks are quoted. Rows that tie on every sort key have no guaranteed order between them, so add a tie-breaker such as an ID column if the order must be repeatable.
Frequently Asked Questions
Why does my CSV sort put 100 before 20?
The column was loaded as text, usually because one cell holds a non-numeric value such as "n/a" or "1,200". Text sorts character by character. Clean or cast the column to a number first, then sort again.
Where do blank CSV cells end up after sorting?
At the end. Empty fields are read as NULL, and NULLs are placed last for both ascending and descending sorts.
How many columns can I sort by?
Up to four. The first key decides the main order, and each Then by key only breaks ties left by the keys above it.
Where do empty values go?
NULL values are always placed last, in both ascending and descending order.
Is the text sort case-sensitive?
Yes. Values are compared by character code, so uppercase letters sort before lowercase. Convert the column to one case first if you want "apple" and "Apple" side by side.
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