How many PDF files can I merge at once?
The Merge PDF page documents a maximum of 20 PDF files per batch and 50 MB per PDF. Large batches can still run into browser memory limits. See /pdf/merge-pdf for the full limitations.
Which image formats can Resize Image handle?
Resize Image accepts JPG/JPEG, PNG, WebP, and GIF, with a documented maximum of 25 MB for one image.
Does Compress PDF preserve selectable text and links?
No. The documented compression workflow renders PDF pages as images, so selectable text, interactive form fields, annotations, and links are not preserved. Open the downloaded result and check it before sharing.
Does the Regex Tester support Python or PCRE patterns?
The Regex Tester uses JavaScript's RegExp engine. Syntax and behavior can differ from Python, PCRE, and .NET regular expressions.
What should I do if JSON formatting fails?
Check for strict JSON syntax such as double-quoted keys and strings, and remove trailing commas. The JSON Validator can help locate parsing errors.
Can I resize an animated GIF and keep the animation?
No. Resize Image keeps a single frame of a GIF, so the animation is lost.
Do the tools upload my file to a Vertex server?
No. The published tool engines do not post your file or calculator input to a Vertex server. Compress PDF, PDF to JPG, and PDF to Word download a PDF.js worker from unpkg.com. Remove Background downloads a model from staticimgly.com. Google Analytics on the page is separate from that processing.
Which calculator should I use for a loan payment?
Use the mortgage calculator when the term is in years and you want principal and interest only. Use EMI when the tenure is already in months. Use loan payoff when you already know the monthly payment and want the number of months. Taxes, insurance, and PMI are not included.
Does the Pakistan GST calculator know the current FBR rate?
No. You type the rate. The page is for PKR amounts and tells you to confirm the rate on the Federal Board of Revenue site. The sales tax calculator uses the same inclusive and exclusive math without the Pakistan label.
What is the difference between compound interest, simple interest, CAGR, and inflation?
Compound interest projects a future value on a compounding schedule. Simple interest uses I = P × R × T with no compounding. CAGR is the annualized rate between a start value and an end value you already know. Inflation applies a constant rate to purchasing power. None of them is a market forecast.
Comparisons with examples: which calculator do you need. Processing detail: how your data is processed.