Simple, Precise & Blazing-Fast Calculators
No pop-ups. No paywalls. Just instant calculations to simplify your logistics, technical workflows, and daily math.
Our Calculator Suite
Professional-grade tools built for speed and accuracy. Pick a category below.
Streamline your supply chain operations and calculate shipping configurations instantly.
Smart sizing estimation tools for household management, hardware, and engineering projects.
Estimate quarterly taxes, deductions, and self-employment liabilities for freelancers and 1099 contractors.
Instant Results
All calculations run locally in your browser. No server round-trips, no waiting.
Precise & Accurate
Built with industry-standard formulas and regularly validated against real-world data.
100% Free
No hidden fees, no premium tiers, no account required. Just open and calculate.
Which Calculator Do You Need?
Most people arrive here with a specific number they need to produce for a carrier, a supplier, or an installer. Below is a short guide to picking the right tool the first time.
Shipping and freight planning
Freight pricing depends on which mode you are shipping. For LTL carriers in North America, rates are driven by NMFC freight class, which is derived from your shipment's density — the freight class calculator works that out from dimensions and weight. Parcel carriers instead bill on whichever is greater, actual or dimensional weight, which the DIM weight calculator computes using your carrier's divisor. For ocean freight and container utilisation, the CBM calculator converts carton dimensions into cubic metres and estimates how many fit in a 20ft or 40ft container.
Before any of those, it usually pays to know how your cartons stack. The pallet calculator shows how many boxes fit on a standard 48x40 GMA pallet or a custom footprint, and how much of the deck area you are actually paying to move. Poor pallet utilisation is one of the most common sources of avoidable freight spend.
Power, backup, and off-grid sizing
Sizing electrical equipment is mostly a question of separating running watts from starting watts. Motor-driven appliances like air conditioners, well pumps, and refrigerators draw a large surge on startup, and a generator that only covers the running load will stall. The generator size calculator accounts for both and adds a safety margin, whether you are sizing for a home standby unit, an RV, or a job site.
For battery-backed systems, the battery runtime calculator estimates how long a UPS or battery bank will carry a given load, factoring in depth of discharge and inverter efficiency rather than assuming the full nameplate capacity is usable. If you are planning a rooftop array, the solar panel calculator works back from your monthly kWh consumption and local peak sun hours to a panel count and system size.
Self-employment and contractor finances
Freelancers and 1099 contractors are responsible for both halves of self-employment tax and for paying it quarterly rather than through withholding — which is where most first-year contractors get caught short. The 1099 tax calculator estimates self-employment tax, federal income tax, and the quarterly instalments to set aside, so you can budget from net rather than gross income.
Frequently Asked Questions
Which calculator should I use for a shipping quote?
It depends on which number your carrier is asking for. For LTL freight in North America you need a freight class, so start with the Freight Class Calculator. For parcel carriers like UPS or FedEx, billing is based on dimensional weight — use the DIM Weight Calculator. For ocean freight and container loading, use the CBM Calculator. If you are working out how much fits on a single pallet before any of that, start with the Pallet Calculator.
Are these calculators really free?
Yes. Every calculator on LetUsCalc is free to use with no account, no trial period, and no usage limit. There is no premium tier holding back features, and we do not gate results behind an email signup.
Is my input data stored or sent to a server?
No. All calculations run entirely in your browser using JavaScript on your own device. Your dimensions, weights, income figures, and load details are never transmitted to us and never written to a database. Closing the tab discards everything.
How accurate are the results?
Each calculator implements the standard published formula for its domain — NMFC density brackets for freight class, carrier divisors for dimensional weight, and standard electrical load math for generator sizing. Results are accurate for planning and estimation. For binding quotes, regulatory filings, or tax returns, confirm the figures with your carrier, licensed electrician, or accountant.
Do the calculators work on mobile?
Yes. Every tool is responsive and built to work on phones and tablets as well as desktop. Because the math runs locally, the calculators also keep working if your connection drops after the page has loaded.
Why Bookmark LetUsCalc?
At LetUsCalc.com,we build native, single-page web applications that execute mathematical formulas instantly on your device. Whether you are scaling commercial shipping freight palettes across the United States or sizing backup generator power margins for your home, our platform strips away complex steps to save you valuable operational time.
Every calculator is optimized for mobile and desktop, works offline after initial load, and respects your privacy - we never store your input data. Bookmark us once, use us whenever you need quick, reliable calculations.