Articles
Practical guides for SmartPlusLab online tools.
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How to Calculate Percentage Change
Learn how to calculate percentage change step by step using the exact mathematical formula, understand positive and negative shifts, and avoid common errors.
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How to Calculate Percentage
Learn how to calculate percentages, find percentage ratios, and measure percentage change using step-by-step instructions and verified examples.
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How to Add a Watermark to Every Page of a PDF
Provide PDF data whose decoded bytes begin with `%PDF-`, enter 1 to 200 characters, choose an opacity from 0.05 to 1.0, and run the operation. A successful result places gray text around the vertical midpoint of every page over its existing content.
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How to Unlock a Password-Protected PDF
Learn how to unlock a password-protected PDF online by providing the correct password. Remove encryption while preserving page count, metadata, and formatting.
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How to Extract Text from a PDF
Provide a PDF, leave page selection empty for the default scope, or enter comma-separated one-based page numbers for a narrower result. The returned text is accompanied by page markers when pages are selected and by total-page and selected-page counts.
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How to Split a PDF into Separate Pages or Ranges
Provide a PDF, choose page-by-page splitting or range mode, and run the operation. The result contains separate split files plus counts and parsed-range information for checking the extraction.
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How to rotate selected pages in a PDF
Use the PDF rotator to turn every page or only selected one-based pages by a chosen angle. It returns a processed PDF with the normalized angle and page counts.
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How to Redact Sensitive Text in a PDF
Submit a valid base64-encoded PDF with a non-empty search value to apply redactions to matching searchable page text. A successful response includes a redacted base64-encoded PDF and counts for processed pages and matched occurrences.
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How to Add Page Numbers to a PDF
Provide a valid PDF as strict Base64-encoded data, choose a supported position and starting number, then apply a page-number format such as `{page}`. A successful run produces modified PDF data with the numbers applied.
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How to Inspect PDF Metadata
Provide a PDF to inspect its page count, byte size, encryption state, version details, and readable metadata values. The reviewed behavior reports inspection data; it does not establish that an edited PDF is produced.
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How to merge multiple PDF files into one
Put at least two Base64-encoded PDF files into the order you want, then process the list to receive one combined PDF. A successful response also includes the number of files combined and pages processed.
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How to Convert PDF Colors to Grayscale
Provide a valid PDF, choose a render resolution from 72 to 200 DPI or use the 120 DPI default, and start the conversion. The successful result is an encoded grayscale PDF with the source page count and effective resolution reported.