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Short, practical how-tos for everyday jobs: UPI QR codes, GST invoices, PDF and photo upload limits, JSON errors, cron schedules and JWTs. Each one links to a free tool that does the work.
How to make a UPI QR code for payments
Get paid by Google Pay, PhonePe, Paytm and BHIM with your own QR code.
Read the guideCommon JSON errors and how to fix them
Trailing commas, quotes, comments and the other mistakes that break JSON.
Read the guideHow to compress a PDF to under 100 KB
Get scans and documents under upload limits without making them unreadable.
Read the guidePassport and visa photo sizes: a practical guide
Sizes, framing and backgrounds that get accepted, and how to print them.
Read the guideHow to resize a photo and signature for online forms
Hit exact pixel and KB limits for photos, signatures and thumb impressions.
Read the guideGST invoice format: what a tax invoice must include
Every field a GST tax invoice needs, with numbering and tax rules.
Read the guideCron expressions explained, with examples
Read and write cron schedules, with copy-ready examples.
Read the guideWhat is a JWT? Decoding and verifying JSON Web Tokens
How JSON Web Tokens work, and how to read and verify them safely.
Read the guideHow to calculate EMI for a home, car or personal loan
The EMI formula with a worked example, and what really changes your total interest.
Read the guideHow to calculate GST: add, remove and split GST
Add GST, take it out of an inclusive price, and split it into CGST, SGST or IGST.
Read the guideHow a SIP works: the formula, an example and step-up SIPs
Rupee-cost averaging, compounding and the maths behind a monthly SIP.
Read the guideHow to calculate percentage: formulas, increase and discount
Every everyday percentage formula in one place, each with a worked example.
Read the guideWhat is Base64? Encoding and decoding explained
How Base64 works, where you meet it, and the one thing it is not: security.
Read the guideJPG vs PNG vs WebP: which image format to use
Pick the right format for photos, logos and web pages, and keep files small.
Read the guideHow to make an ATS-friendly resume that gets read
A layout and wording that both software and recruiters can read in seconds.
Read the guideSalary slip format: what a payslip must show
Earnings, deductions, PF, ESI and net pay: the fields a good payslip carries.
Read the guideEXIF data: what your photos reveal and how to remove it
Photos can carry your location and device. See what is inside and strip it.
Read the guideUnix timestamps explained: seconds, milliseconds and time zones
What epoch time is, how to read it, and the mistakes that shift dates.
Read the guideHow to merge PDF files into one, in the right order
Combine PDFs and scans into one file, reorder pages and keep the size small.
Read the guideHow to password protect a PDF, and remove the password
Lock a PDF with a password on your own device, and remove it when you know it.
Read the guideRegex cheat sheet: patterns you will actually use
Character classes, quantifiers, groups and copy-ready patterns, explained briefly.
Read the guideHow to make a strong password you can actually manage
Length, uniqueness and a manager: the three habits that matter most.
Read the guideJSON vs YAML: differences, when to use each and how to convert
Which format to pick for config and APIs, and how to switch between them.
Read the guideFree for everyone, kept free by you.
No paywall, no sign-up and no watermarks. If a tool saved you time, you can chip in any amount by UPI to keep Nova Free Tools running.