Articles
Practical guides for SmartPlusLab online tools.
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How to Calculate Age from Date of Birth
Learn how to calculate age from date of birth using step-by-step calendar rules, practical US date examples, and cutoff guidelines for any target date.
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How to Convert Time Durations Between Units
Enter a duration, choose its source and destination units, and review the converted number with its readable breakdown. Hours to minutes are selected by default, and other supported duration units can be chosen when they match your input.
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Plain Text to HTML: A Practical Formatting Guide
Enter plain text, choose the character and formatting options, and convert it to HTML. Paragraph and newline handling begin enabled, while matching HTTP or HTTPS text can become linked when you select that option.
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How to Check an SSL Certificate for a Hostname
Enter a hostname and optional port, then start the check to view available TLS certificate and connection details. An explicitly empty host returns error data, while an unconvertible port uses `443`.
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How to Generate an RSA Key Pair in PEM Format
Generate the corresponding RSA public and private key pair, then use the two returned PEM text blocks separately. The optional size starts at 2048 and also accepts 3072 or 4096.
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How to Check if a Network Port Is Open on a Host
Enter a host, selected comma-separated ports, and an optional timeout, then start the check. Read the per-port outcomes and completed summary to identify which supplied entries were recorded as open, closed, or affected by an error.
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How to Analyze HTTP Headers from Copied Text
Paste HTTP header text into HTTP Headers Info to have it parsed, normalized, and grouped into recognized, custom, and malformed entries. Leaving the input empty returns a no-header result with descriptions of common header names.
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How to Generate a .gitignore Template
Choose Python, Node, Java, Go, or Rust to generate its predefined `.gitignore` template. Leave the language input empty when Python should be selected by default.
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How to Validate a Cron Expression and Find the Next Runs
Enter a five-field cron expression to validate it and calculate its next five run times from the current UTC time. Successful results are returned as five UTC ISO-formatted date-time strings; valid schedules can still fail if no match occurs within ten years.
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How to Create a ZIP File from Multiple Text Files
Supply named text entries, create the ZIP archive, and review its base64 data, byte size, filename, and entry count. Without a file list, the tool uses its built-in example entry.
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How to Get YouTube Thumbnail URLs from a Video ID
Enter a YouTube video identifier or a supported video URL, select a thumbnail resolution, and run the tool to generate thumbnail URLs. It constructs HTTPS URLs rather than downloading thumbnail image files.
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How to Convert YAML to JSON
Enter YAML text, choose the JSON indentation setting and optional key sorting, then start the conversion. Empty input produces an empty JSON object, while malformed YAML produces an unsuccessful result.