By job
Self-hosted business apps 34
Open-source business software you run on your own server: failed-payment recovery, cancellation flows, MRR and revenue recognition, lifecycle email, referrals…
Marketplace seller tools 117
Price a listing, a fee change, or a program before you opt in — with your own cost of goods in the arithmetic.
Trade & contractor bids 189
Bid a job the way the trade does — materials, crew hours, burden, overhead, and what the extras really cost — then print the customer a proposal with the scope…
Getting paid & job margin 57 Cleaning, restoration & insulation 31 Roofing, siding & gutters 13 Windows, doors & garage 9 HVAC, plumbing & electrical 20 Interior finishes & remodels 24 Concrete, masonry & site work 14 Landscape, deck & pool 21
Restaurant, bar & food truck pricing 69
What a plate, a pour, or a booked event actually earns once food cost, waste, and the hours behind it are in the arithmetic…
Service business pricing & quotes 197
Price a visit, a route, a booking, or a licence — for the service businesses that quote work without bidding a construction job.
Logistics, freight & cloud cost 36
Normalise a quote, audit a bill, or size a transfer window before you sign for it.
Compliance checks & evidence records 118
Produce a dated record of what you checked. Observations you act on — never a determination made on your behalf.
UK tax, pay & benefits 56
Take-home pay, Self Assessment, dividends, IR35, VAT, pensions, statutory pay and the 100k trap — worked with HMRC rates for the current tax year, in your browser.
Back-office money & contracts 216
Cash timing, contract terms, and the break-even behind a price change — the arithmetic that happens after the job is won.
CI checks & developer gates 177
Audit a GitHub Actions workflow for injection, over-broad permissions, unpinned actions and cache poisoning; tell a starved runner from a real failure…
Creator & solo earner income 95
What one person actually earns from their own work — a print, an ad slot, a delivery shift, a repo, a job application. Priced or checked before you commit to a number.
Research algorithms & ML 3
Methods from published research papers, run on your own data in your browser and cited: changepoint detection, conformal prediction intervals…
Learning & practice 5
Learn a language or a technical skill by doing it: hands-free speaking drills, graded audio stories, and project-first engineering lessons, free in your browser.
Open hardware, robots & house plans 4
Things you can build, change and sell: MIT-licensed robot CAD with laser-cut and 3D-print files, firmware…
More free tools 5
Everything else that runs entirely in your browser.
By type
Self-hostable apps 67
Business software that runs as your own server: deploy a copy to your own cloud account with your own keys, and you own the data.
Self-hosted business apps 33 Marketplace seller tools 8 Trade & contractor bids 3 Restaurant, bar & food truck pricing 2 Service business pricing & quotes 3 Logistics, freight & cloud cost 3 Compliance checks & evidence records 2 UK tax, pay & benefits 2 Back-office money & contracts 8 Creator & solo earner income 3
Command-line tools 192
Checks that run in a terminal or a CI pipeline; each page explains what it looks for and how to install it.
Marketplace seller tools 9 Trade & contractor bids 14 Restaurant, bar & food truck pricing 5 Service business pricing & quotes 11 Logistics, freight & cloud cost 2 Compliance checks & evidence records 9 Back-office money & contracts 17 CI checks & developer gates 114 Creator & solo earner income 6 Research algorithms & ML 3 Open hardware, robots & house plans 1 More free tools 1
By trade or business
Roofers 12
Free roofing bid calculators: asphalt, metal and flat roofs, gutters, gutter guards, siding and skylights. Price the job, print the proposal, keep the margin.
HVAC contractors 10
Free HVAC pricing tools: furnace, boiler and mini-split bids, maintenance agreements, repair price tiers, duct cleaning and heat pump vs furnace comparisons.
Plumbers 10
Free plumbing pricing tools: flat-rate pricing, water heaters, sewer lines, hydro-jetting, sump and well pumps, septic pumping and french drains.
Electricians 8
Free bid calculators for electricians: panel upgrades, EV chargers, standby generators, solar PV, landscape lighting and security camera installs.
Painters 8
Free painting estimate calculators: interior and exterior painting, cabinet refinishing, deck staining, epoxy floors, drywall and popcorn ceilings.
Cleaning businesses 14
Free quote calculators for house cleaning, janitorial contracts, carpet, window and duct cleaning, pressure washing, junk removal and Airbnb turnovers.
Landscapers 16
Free bid calculators for landscapers: lawn care, aeration, sod, irrigation, pavers, retaining walls, fences, tree work, snow removal and landscape lighting.
Pool & hot tub pros 6
Free pricing tools for pool service companies: weekly route pricing, openings and closings, plaster and vinyl liner replacement, and hot tub installs.
Auto detailing & repair 10
Free pricing calculators for mobile detailing, window tint, vehicle wraps, auto glass, dent repair, towing and a repair shop's effective labour rate.
Etsy sellers 5
Free Etsy seller tools: fee and profit calculator, Etsy Ads ROI, monthly statement profit, a listing CSV check and statement-to-bookkeeping export.
eBay sellers 5
Free eBay seller tools: fee calculator, Promoted Listings ROI, transaction report analysis, File Exchange check and payouts to bookkeeping entries.
Amazon sellers & KDP authors 10
Free Amazon seller tools: FBA fee and profit calculator, PPC search terms, aged inventory fees, reimbursement claims, KDP royalties and settlements.
Shopify stores 12
Free tools for Shopify stores: fee calculator, payout profit, discount leakage, inventory reorder planning and product, customer and inventory CSV checks.
Resellers 15
Free fee calculators for resellers on Poshmark, Mercari, Depop, Grailed, Whatnot, StockX and Reverb, plus a where-to-sell comparison and thrift picker.
Landlords & hosts 27
Free landlord tools: rent increases, renewals, security deposit returns, rent rolls, DSCR, cap rate, Schedule E, and Airbnb pricing, cleaning fees and payouts.
Freelancers 40
Free freelancer tools: rate and retainer calculators, proposals, contracts, invoices, late payers, tax set-aside, self-employment tax and SEP-IRAs.
Photographers & videographers 7
Free tools for photographers and videographers: wedding and real estate shoot profit, commercial licensing fees, photo booth quotes and batch editing.
Wedding & event pros 19
Free tools for event businesses: DJ gigs, florists, officiants, venues, mobile bars, photo booths, bounce house and tent rentals, and seating charts.
Restaurants, cafes & bars 21
Free tools for restaurants, cafes, bars and breweries: recipe costing, menu engineering, pour cost, tip pools, labour, delivery fees and catering.
Pet businesses 15
Free tools for pet businesses: dog grooming prices and profit, dog walking routes, boarding and daycare pricing, pet sitting fees and vet pricing.
Creators 18
Free creator tools: YouTube RPM, sponsorship and brand deal rates, UGC rates, media kits, and Patreon, Substack, Twitch and Gumroad payouts.
Childcare providers 5
Free tools for childcare businesses: tuition pricing, break-even for a centre, enrollment mix by age group, and nanny tax for families employing a carer.
Tutors & teachers 11
Free tools for tutors and instructors: package pricing, effective hourly rate, weekly schedules, music studio profit, driving lessons and courses.
Truckers & owner-operators 9
Free trucking tools: owner-operator cost per mile, load chaining, per diem, IFTA fuel tax, detention pay, LTL freight class and broker load margin.
Farms & homesteads 18
Free tools for small farms: crop mix, CSA share pricing, farmers market booths, cattle margins, hay prices, custom farm rates and cottage food pricing.
Therapists & clinics 10
Free tools for private practices: payer mix, the therapy 8-minute rule, good faith estimates, ABA authorizations, dental PPO write-offs and more.
Salons & beauty pros 8
Free tools for salons and beauty pros: booth rent vs commission, barber chair profit, lash and esthetician pricing, nail booth rent and tattoo pricing.
Reading
Guides: the explainers written beside each tool. Comparisons: products compared side by side. Research: the open research portfolio.