A
AiTechWorlds
AiTechWorlds
Visualize Radix Sort processing numbers digit by digit with stable counting passes, in linear O(nk) time.
def radix_sort(a):
mx = max(a)
exp = 1
while mx // exp > 0:
out = [0]*len(a); cnt = [0]*10
for x in a: cnt[(x//exp)%10] += 1
for i in range(1, 10): cnt[i] += cnt[i-1]
for x in reversed(a):
d = (x//exp)%10; cnt[d] -= 1; out[cnt[d]] = x
a[:] = out; exp *= 10Radix Sort sorts numbers digit by digit (least-significant first) using a stable counting sort per digit, achieving linear time for fixed-width integer keys.
| Best | O(nk) |
| Average | O(nk) |
| Worst | O(nk) |
| Space | O(n + k) |
| Stable | Yes |
| In-place | No |
The Radix Sort Visualizer animates how Radix Sort works: it sorts numbers digit by digit, from least-significant to most-significant, using a stable counting sort on each digit. Radix Sort runs in O(nk) time for k-digit numbers and is stable, but uses O(n + k) extra space. It is non-comparison based, so it can beat O(n log n) for fixed-width integer keys.
Generate an array
Click New Array or adjust the size slider for a random integer dataset.
Play the animation
Press Play to watch each digit pass redistribute the numbers.
Step and scrub
Step forward/back or drag the timeline to follow each digit placement.
Read the synced code
The highlighted pseudocode line tracks the digit loop; switch tabs for C++, Java, Python, or JavaScript.
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Last reviewed on June 14, 2026 by the AiTechWorlds Tools Team. All processing runs locally in your browser.