Free checkers and calculators for the rules that changed in 2026
Each tool runs in your browser on your own numbers or your own file — free, no account. The full version is a one-time licence.
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Most used right now
Shop by who you are
Online sellers
See all 26Fees, payouts and margins on Etsy, eBay, Shopify, TikTok Shop, Amazon KDP and other marketplaces.
Traders and investors
See all 8Trading journals, wash-sale and capital-gains checks for this tax year.
Landlords and real estate
See all 9Rental yield, rent rules and deal numbers.
Creators and designers
See all 11Post plans, design kits, LUTs and the numbers behind sponsorships and platform payouts.
Self-employed and small business
See all 80Payroll, tax and invoice numbers with this year's rates and deadlines.
Developers and compliance teams
See all 267Checks of code, files and sites against a dated rule — each finding names the article and the line.
More tools
See all 47Everything else that stands today.
Start from your side
By rule and country
Most installed
Oracle JDK License Gate
VS Code extension
Finds the Java lines in your build that Oracle now bills for, and the free line that replaces each one
VS Code Marketplace: 693 installs
Free in the browser · full version $29 once
pypdf Migration Check - PyMuPDF AGPL Licence Gate
VS Code extension
Map every fitz / PyMuPDF line to its pypdf, pdfplumber or pypdfium2 replacement
VS Code Marketplace: 147 installs
Free in the browser · full version $29 once
Conda License Lint: Anaconda defaults channel
VS Code extension
Finds every environment.yml and .condarc line that pulls from Anaconda's licensed repository
VS Code Marketplace: 37 installs
Free in the browser · full version $29 once
Python Upgrade Lint: Removed Stdlib 3.12-3.14
VS Code extension
Find every import and call that Python 3.12, 3.13 or 3.14 removed before you leave Python 3.10 (end of life October 2026). 43 rules.
VS Code Marketplace: 36 installs
Free in the browser · full version $29 once
Firmware Release Gate for sdkconfig and prj.conf
VS Code extension
Finds the build-config lines that ship an ESP-IDF or Zephyr device with secure boot off, a debug port open, unsigned images or plaintext…
VS Code Marketplace: 23 installs
Free in the browser · full version $29 once
pyproject.toml Release Gate (PEP 639)
VS Code extension
19 date-aware checks on the [project] metadata that decides whether your next release uploads
VS Code Marketplace: 22 installs
Free in the browser · full version $29 once
Python 3.10 End of Life — Pin Check & Fix
VS Code extension
Python 3.10 end of life was 2026-10-01 (3.10.22 final, no more security patches).
VS Code Marketplace: 21 installs
Free in the browser · full version $29 once
Coverage Gate Lint
VS Code extension
Finds the coverage gates in your repo that can never fail a build
VS Code Marketplace: 20 installs
Free in the browser · full version $29 once
Maven Central Publish Gate
VS Code extension
Read a pom.xml the way the Central Portal reads it, before you burn a release tag
VS Code Marketplace: 15 installs
Free in the browser · full version $29 once
Open VSX Publish Gate - vsce & ovsx preflight
VS Code extension
package.json and publish-workflow check for VS Code extension authors: every vsce and Open VSX blocker with its line and fix
VS Code Marketplace: 12 installs
Free in the browser · full version $29 once
WCAG 2.2 CSS Lint - Focus & Target Size
VS Code extension
Reads your stylesheet and names the success criterion each rule breaks, including the three WCAG 2.2 added that WCAG 2.1 linters never…
VS Code Marketplace: 12 installs
Free in the browser · full version $29 once
Linker Map Auditor - FLASH & RAM budget for GNU ld map files
VS Code extension
Read the .map your linker already wrote and see, in exact bytes, which object file is spending your FLASH and RAM - and by how much you…
VS Code Marketplace: 12 installs
Free in the browser · full version $29 once
Newest
Project Management Theme: Obsidian Fixed-Fee Budget Board
Obsidian theme
For freelancers and agency PMs on fixed-fee client work: a contrast-checked light and dark theme plus a project board that flags hours…
Free in the browser · full version $29.90 once
Recruiting Workflow Template for n8n: UK, US and Germany Candidate Retention Dates
UK rejection window now 6 months (from 2026-10-01). 6 n8n workflows run your pipeline in your own Google Sheet and stamp a delete-by date…
Free in the browser · full version $199 once
Inventory Management Template — Reorder Point & Safety Stock
Spreadsheet calculator
Reorder at 224 units, not 120: in the worked example a supplier running 14 days instead of 10 while sales hit 16 a day leaves 104 units…
Free in the browser · full version $21 once
Building Product Compliance Checklist 2026: EU CPR Sales-at-Risk Check
Spreadsheet calculator
For EU construction product manufacturers and importers under CPR 2024/3110: split your EU sales by declaration route (hEN, ETA, no DoP).
Free in the browser · full version $21 once
Startup Financial Model Template: 2026 US Payroll Runway
Spreadsheet calculator
Your runway is shorter than salaries say: every 2026 US hire also costs 6.2% Social Security up to the 184,500 wage base, 1.45% Medicare,…
Free in the browser · full version $21 once
Project Management UI Kit — Kanban Board, Task Status & Milestone Components with WCAG 2.2 AA States (Figma + Sketch)
Figma kit
Project management UI kit for SaaS product designers who sell to US federal agencies (Section 508) or EU public buyers (EN 301 549): a…
Free in the browser · full version $168 once
Mobile Lightroom Presets for Real Estate Listing Photos
LUT pack
22 presets for real estate agents who shoot listings on a phone, one per light: tungsten rooms, mixed window light, LED bathrooms, overcast…
Free in the browser · full version $44 once
Cold Email Laws by Country: Client List Consent Calculator
Spreadsheet calculator
Writing cold outreach for clients in several countries? US and UK company contacts run on opt-out rules; Canada (CASL, up to $10 million…
Free in the browser · full version $21 once
Chart of Accounts Template: Schedule C Meals & Entertainment
Spreadsheet calculator
Split one lumped Meals & Entertainment account the way IRC §274 does: meals 50%, entertainment 0%, gifts $25 per person.
Free in the browser · full version $21 once
PostgreSQL 17 Upgrade Map: Azure Extended Support
VS Code extension
Finds Azure PostgreSQL 11-14 version pins in Terraform, with the monthly Extended Support bill and the version = "17" line
Free in the browser · full version $29 once
Nexus Repository Pricing: Verdaccio Migration Map
VS Code extension
Verdaccio, Reposilite and Pulp lines for every Sonatype Nexus Repository URL before Community Edition's 40,000-component cap
Free in the browser · full version $29 once
conda-forge PyTorch Channel Migration Check
VS Code extension
Flags -c pytorch, pytorch:: prefixes, pytorch-cuda, cpuonly and torch pins below 2.6.0 in environment.yml, Dockerfiles and CI YAML, with…
Free in the browser · full version $29 once
Subscriptions and team keys
Every linter — annual keyTeam key — $149 onceAll prices