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Plaintools

No upload. No account.

A utility shed that stays on your device.

Plaintools runs every converter and generator in the browser. Files, tokens, IBANs, and campaign URLs never leave the tab. Use it when you do not want another paste-bin with a login.

Live tools

SEO

UTM generator

Add source, medium, campaign, term, and content parameters to a URL you already own.

SEO

Slug generator

Turn a title into a lowercase URL slug, with stop words stripped and unicode transliterated.

Dev

JWT decoder

Read a JWT header and payload, with human timestamps and an expired flag. The token stays in the tab.

SEO

JSON-LD generator

Build live JSON-LD for FAQ, HowTo, Article, Product, LocalBusiness, Breadcrumb, and Organization.

Convert

HEIC converter

Convert iPhone HEIC/HEIF photos to JPEG or PNG in the browser.

Dev

Text diff checker

Compare two texts with a live line and word diff. Optional ignore-whitespace.

Checkers

IBAN validator

Check an IBAN checksum and country length. The number never leaves this tab.

Dev

Hash generator

Calculate SHA-256, SHA-384, SHA-512, and SHA-1 checksums for text or local files.

Dev

Timestamp converter

Convert Unix epoch timestamps in seconds or milliseconds to ISO 8601, UTC, and local time.

Dev

CSV to JSON converter

Convert CSV records to a JSON array of objects with header mapping and type detection.

Finance

Pool financing calculator

Calculate swimming pool loan monthly payments, interest, down payment, and amortization schedule.

Finance

XIRR calculator

Calculate annualized internal rate of return for irregular, dated investments and cash flows.

Build

Roof pitch calculator

Calculate roof pitch (x/12), slope angle in degrees, grade percentage, and common rafter length.

SEO

Open Graph generator

Generate Open Graph and Twitter Card meta tags with live social preview cards.

Dev

Subnet calculator

Calculate IPv4 network address, broadcast, usable range, subnet mask, and host capacity from CIDR.

SEO

Favicon generator

Generate multi-resolution favicon.ico, 16/32/48 PNGs, apple-touch-icon, and web manifest locally.

SEO

Robots.txt generator

Generate RFC 9309 robots.txt files with allow/disallow paths, bot groups, sitemaps, and crawl delays.

Shipping

Etsy fee calculator

Estimate Etsy listing fees, 6.5% transaction charges, payment processing, and net profit margins.

Dev

CIDR calculator

Calculate IPv4 CIDR blocks, network address, broadcast address, netmask, usable hosts, and wildcard mask.

SEO

Schema checker

Validate Schema.org JSON-LD syntax, @context, @type, and required fields for FAQ, HowTo, Article, and Product.

Convert

Image compressor

Compress JPEG, PNG, and WebP images with adjustable quality, scaling, and live file size preview.

Finance

Break-even calculator

Calculate break-even units, revenue, contribution margin, and target profit volume milestones.

Convert

GIF compressor

Compress animated and static GIFs in your browser by downscaling dimensions, quantizing colors, and dropping frames.

Text

Case converter

Convert text between lowercase, UPPERCASE, Title Case, Sentence case, camelCase, PascalCase, snake_case, and kebab-case.

Text

Readability checker

Calculate Flesch Reading Ease, Flesch-Kincaid Grade Level, Gunning Fog, and reading time estimates client-side.

Finance

Retirement corpus calculator

Calculate the required retirement corpus, future monthly living expenses adjusted for inflation, and required monthly savings.

Coming next

  • AVIF converter

    Same privacy model as HEIC: decode in the tab, download a JPG or PNG. Not shipped yet.

  • robots.txt checker

    Paste a robots file and a path; see which rules match. Parsing only, no crawl.

Browse by job: SEO · Dev · Text · Convert · Checkers · Finance · Build · Shipping.