# All tools

Every 17x7 calculator and utility, grouped by who uses it. Each one runs in your browser and shows the arithmetic behind its answer.

## For online sellers

Marketplace fees, margins and the price you need to charge.

- [Etsy Fee Calculator](https://17x7.com/tools/etsy-fee-calculator/): Every Etsy fee on one order — listing, transaction, processing, Offsite Ads — and what you actually keep. (`6.5% + 3% + $0.25 + $0.20`)
- [Amazon FBA Calculator](https://17x7.com/tools/amazon-fba-calculator/): Size tier, fulfillment fee, referral fee and storage for one unit, with margin and ROI. (`tier(L×W×H, lb) → fee`)

## For contractors and DIY builders

Slopes, spans and material takeoffs, with the code limits that apply.

- [Roof Pitch Calculator](https://17x7.com/tools/roof-pitch-calculator/): Pitch from rise and run (or angle) plus degrees, slope, rafter length, squares and shingle bundles. (`atan(6 ÷ 12) = 26.57°`)
- [Deck Material Calculator](https://17x7.com/tools/deck-material-calculator/): Boards, joists, hangers and screws for a rectangular deck — cut-aware, with the least-waste board length. (`⌈144″ ÷ 5.6875″⌉ = 26 rows`)

## For developers and AI agents

The time zone and cron tools also answer over the JSON API and MCP; the JSON Schema, YAML and robots.txt tools run only in your browser.

- [Time Zone Converter](https://17x7.com/tools/time-zone-converter/): Convert one moment into up to 20 zones: DST gaps and repeats flagged, next clock changes, working hours, UTC math. (`UTC = local − offset`)
- [Cron Expression Generator & Explainer](https://17x7.com/tools/cron-expression/): Paste a cron expression for plain English, a field-by-field breakdown and next runs in any time zone, or build one. (`*/15 9-17 * * 1-5`)
- [JSON Schema Validator](https://17x7.com/tools/json-schema-validator/): Check JSON against a JSON Schema (2020-12, 2019-09, 07, 04): every error as a JSON Pointer, most specific first. (`valid(instance, schema)`)
- [JSON Schema Generator](https://17x7.com/tools/json-schema-generator/): Paste sample JSON and get a draft 2020-12 schema with types, required keys and formats, checked against your sample. (`{ "a": 1 } → "integer"`)
- [YAML to JSON Converter](https://17x7.com/tools/yaml-to-json/): Convert YAML to JSON and back in your browser, with line-numbered warnings where YAML 1.1 and 1.2 disagree. (`country: NO → false`)
- [Robots.txt Tester](https://17x7.com/tools/robots-txt-tester/): Paste a robots.txt and test any URL: verdict, deciding rule and line, plus ten search and AI crawlers at once. (`Allow: /a/b > Disallow: /a`)

## Reference pages

- [Roof Pitch to Degrees Chart](https://17x7.com/tools/roof-pitch-calculator/pitch-to-degrees/)
- [Etsy Price Calculator (target margin)](https://17x7.com/tools/etsy-fee-calculator/etsy-price-calculator/)

## What makes a 17x7 tool

Each calculator is built around one job that people do for real money or real materials — pricing an Etsy listing, checking whether an Amazon product still makes money after fees, ordering shingles, buying deck boards. We would rather do a handful of these properly than publish hundreds of thin converters.

Every page explains the formula, walks through a worked example, lists the limits of the method, and answers the questions people actually ask. Numbers that change — marketplace fees, code tables — carry a source and the date we last checked it.

Missing a calculator you need for work? [Tell us what it should do](https://17x7.com/contact/).

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Source: https://17x7.com/tools/ · Last updated: 2026-10-11