Format times and dates with pattern letters in Pine Script

TL;DR
Combine pattern letters with str.format() so any timestamp can be rendered exactly the way your indicator or alert needs.

At a Glance


Difficulty	Beginner
Time to implement	10-15 min
Category	Strings

Quick Actions

Quick Start

//@version=5
indicator("Pattern letter demo", overlay=false)

fmt = str.format(
    "Session starts {0,date,EEEE d MMM yyyy} at {0,time,HH:mm:ss}",
    time("D")
)

label.new(bar_index, close, fmt)

Why It Matters

Indicators and alerts rarely want timestamps in the default US format. Pattern letters let you define your own output: 24-hour time, ISO dates, day names, shortened months, you name it. With them, you can create consistent UI copy, logs, and alert messages that match your audience or trading journal.

What You’ll Learn

The difference between format specifiers and pattern letters
How to combine pattern letters inside str.format() placeholders
Common patterns for dates, times, and combined strings
Handling literal text and whitespace inside placeholders

Quick Reference

Call	Purpose
`str.format(template, value...)`	Builds strings from placeholders that can include pattern letters.
`str.format_time(timestamp, timezone, pattern)`	Formats timestamps for specific time zones using pattern letters.
`time(resolution)`	Supplies the timestamp you want to format.
`time("D")`	Returns the start of the current exchange day—handy for date labels.
`label.new(...)`	Displays formatted timestamps on the chart.

Popular Pattern Letters

Letter	Meaning	Example
`y`	Year	`yyyy` → `2025`
`M`	Month in year	`MMM` → `Feb`
`d`	Day in month	`dd` → `05`
`E`	Day of week	`EEEE` → `Tuesday`
`H`	Hour (24h)	`HH` → `18`
`h`	Hour (12h)	`hh` → `06`
`m`	Minutes	`mm` → `09`
`s`	Seconds	`ss` → `32`
`a`	AM/PM marker	`a` → `PM`
`z`	Time zone short name	`zzz` → `EST`

Implementation Blueprint

Choose the timestamp you want to format
Decide whether to use the bar time (time), session start (time("D")), or a request to another resolution.
```
barStart   = time
sessionOpen = time("D")
```
Compose pattern letters inside a placeholder
Pattern letters appear after the date or time specifier inside the {index,type,pattern} placeholder.
```
isoString = str.format(
    "{0,date,yyyy-MM-dd}T{0,time,HH:mm:ss}",
    barStart
)
```
Render the formatted string in your UI or alerts
Display the result on chart elements or use it inside alertcondition() messages.
```
label.new(bar_index, high, isoString, style=label.style_label_up)
alertcondition(true, "ISO timestamp", isoString)
```

Example Playbook

//@version=5
indicator("Timestamp formatter", overlay=true)

fmtIso = str.format(
    "{0,date,yyyy-MM-dd} {0,time,HH:mm:ss}",
    time
)

fmtFriendly = str.format(
    "{0,date,EEEE, MMM d} at {0,time,h:mm a zzz}",
    time("D")
)

label.new(bar_index, high, fmtIso, style=label.style_label_down, textcolor=color.white, bgcolor=color.new(color.green, 65))
label.new(bar_index, low, fmtFriendly, style=label.style_label_up, textcolor=color.white, bgcolor=color.new(color.blue, 65))

Why this works.

Pattern letters give you ISO-style and reader-friendly formats without manual string slicing.
Whitespace inside the placeholder is preserved exactly—control spacing inside the pattern.
Literal text wrapped in single quotes remains untouched (`'Session'` prints the word instead of interpreting letters.

Pro Tips & Pitfalls

Wrap literal text in single quotes inside the placeholder: {0,time,'Session starts at' HH:mm}.
Combine date and time placeholders if you want to mix language-specific day names with numeric times.
Use str.replace() if you need to localise month names or adjust punctuation after formatting.
For consistent time zone output, prefer str.format_time(timestamp, "exchange", pattern) or specify a time zone explicitly.

Troubleshooting & FAQ

My placeholder returns an error

Ensure you include a format type (date or time) before the pattern letters, e.g. {0,time,HH:mm}. Omitting it throws a run-time error.

Why does whitespace disappear?

Whitespace outside the pattern letters is significant—" {0,time,HH:mm} " keeps spaces, but inside the pattern you must add spaces explicitly (' at ').

Key Takeaways

Pattern letters let you define custom date and time strings in Pine Script.
Place pattern letters after date or time specifiers inside str.format() placeholders.
Use literal quotes and whitespace intentionally to keep output readable.
Combine str.format() and alertcondition() for rich, informative notifications.

Keep Going

Open AI Editor to apply the pattern with guided assistance
Browse Strategy Examples for ready-to-run templates
Connect to Live Trading when you are ready to automate

Adapted from tradingcode.net, optimised for Algo Trade Analytics users.