Date.toISOString() ISO format string
Last updated: 2026-09-09
Date.toISOString() ISO format string
toISOString returns an ISO 8601 string (YYYY-MM-DDTHH:mm:ss.sssZ) always in UTC.
| Category | Dates |
|---|---|
| ES version | ES5 |
📝 Syntax
const iso = date.toISOString();Returns：ISO 8601 format string.
Mutates the original：No (returns a new value)
▶ Example
Edit the code, press Run, and see the result in the output panel:
Output：
2026-09-09T07:01:00.940Z
2026-09-09💡 Tip toISOString().slice(0, 10) is the simplest YYYY-MM-DD.
⚠️ Warning Always UTC — local date may differ by hours. Format manually for local dates.
🌐 Browser support
| Browser |  Chrome |
 Edge |
 Firefox |
 Safari |
 Opera |
|---|---|---|---|---|---|
| Date.toISOString() | ✓ v1 | ✓ v12 | ✓ v1 | ✓ v1 | ✓ v1 |
| Supported by all modern browsers | |||||
🏷️ Related Items
💡 Related Cases
More case studies coming soon — check back later.
📚 Related Tutorials
❓ FAQ
QWhat are T and Z in ISO format?
AT separates date and time; Z means UTC timezone.
QDoes toISOString give local date?
ANo — always UTC. slice(0, 10) may be off by a day.
QWhat format for database serialization?
AtoISOString() — universally supported.
