ToolGrit: Free Industrial Calculators Built by Someone Who Actually Uses Them

I’ve spent more than to two decades working in industrial maintenance, research labs, and field operations. Mud logging in the Bakken, core analysis at a research facility, and now electrical and instrumentation planning at a sugar processing plant. One thing that never changed across all of those jobs: when you need a quick calculation, your options are either a $200 software license, a spreadsheet somebody built in 2003 and nobody remembers how it works, or doing the math on scratch paper next to your coffee.

That’s why most of my built effort recently has been focused on ToolGrit.

What It Is

ToolGrit is a collection of over 200 free online calculators covering trades and industrial work. Electrical, HVAC, agriculture, water treatment, machinist work, drilling, emissions, safety, and more. No login required. No ads. No app to download. You open the page, plug in your numbers, and get an answer.

Every tool runs right in your browser. There’s nothing to install, no account to create, and your inputs stay on your device. The calculators cover real tasks that tradespeople, operators, planners, and engineers deal with on a daily basis.

Who It’s For

If you’ve ever needed to figure out conduit fill, size a transformer, estimate concrete for a pad, calculate pump flow, or work out evaporation losses on a holding pond, these tools were built with you in mind. The target audience is the person standing in a control room, a shop, or out at a job site who needs a reliable answer without digging through a textbook.

Categories include:

• Electrical and NEC code calculators
• HVAC load and ductwork sizing
• Water treatment and municipal utilities
• Agriculture and grain storage
• Machinist and fabrication tools
• Emissions and environmental compliance
• Industrial safety and maintenance planning
• Geology and drilling calculations
• Residential estimating

Why I Built It

Most online calculator sites are either loaded with ads, limited to a handful of tools, or clearly built by someone who has never worked in the field. I wanted something that covered the range of calculations I’ve actually needed across different industries, with clean results and no nonsense.

The tools include PDF and CSV export so you can save your work or hand it to someone else. Many of them generate shareable URLs, so you can send a specific calculation to a coworker with all the inputs already filled in (this is done with a coded link not tracking). There’s also a Pro tier for $6, $15, and $200 a year if you want to support the project, but the core tools are free and staying that way.

Built Different

Every calculator gets checked against published references and known values before it goes live. The math matters. If a tool gives you the wrong wire size or the wrong pressure drop, that’s not just an inconvenience. I treat accuracy the same way I treat it at work: verify it, then verify it again.

New tools get added regularly. If you work in trades, maintenance, engineering, or operations, take a look. Odds are there’s something in there you’ll use this week.

If you don’t see what you want let me know. 

Free DuPont Schedule Generator – Simple 24/7 Shift Planning

I put together this DuPont Schedule Generator in Excel to make my own shift planning easier and since I don’t use it anymore, I’m sharing it here for anyone who might find it helpful.

The DuPont shift schedule is a rotating 12-hour system that provides continuous 24/7 coverage, with a nice bonus of a full week off every cycle. If you’re using this kind of rotation, this tool makes it easy to visualize your schedule at a glance.

How It Works:

Just open the file and enter a start date  the first day of a set of four consecutive workdays right before your week off. The rest of the year will auto-fill based on that start point.

What You’ll Get:

• A clear, color-coded layout

• A full-year overview at a glance

• No formulas to mess with — just plug in the date and go

It’s completely free to download and use. I built it for myself, but maybe it’ll save you a few headaches too.

Let me know if it comes in handy!