Free calculators
The calculators I built for my own desk.
Freight quotes, packaging weight, kitchen conversions. A few hundred everyday sums, free, no signup, formula shown on every page.
What this site is
Stack Frame is the set of calculators I kept rebuilding in a spreadsheet, so I turned each one into a page and stopped rebuilding. Freight and packaging figures come from work. Kitchen conversions, pet portions and plant arithmetic came from the weekend, which is why the mix looks odd.
Every page states the formula it uses, where that formula came from, and the assumption your result depends on. Nothing needs an account or an upload, and the figures you type in never leave your browser. Treat a result as an estimate to check, not an answer to act on.
The five areas
Most of these are things I needed myself at least once, which is the only reason they exist.
Business & Trade
96 calculatorsFreight class, pallet loading, air and sea cargo costs, and the arithmetic behind a campaign.
- Freight Class Calculator
- Pallet Density Calculator
- Air Cargo Cost Calculator
- Container Load Planner
- CPC Calculator
- LTL Freight Class Calculator
Lifestyle
50 calculatorsKitchen conversions, pet and plant arithmetic, and hobbies that turn out to need a formula.
- Cooking Conversion Calculator
- Dog Food Calculator
- Espresso Shot Volume Calculator
- Litter Box Cleaning Frequency Calculator
- Knitting Cast-On Stitch Calculator
- Flower Pot Drainage Layer Calculator
Legal
14 calculatorsCost estimators for the processes where the price normally shows up too late.
- Attorney Contingency Fee Calculator
- Family Law Mediation Cost Estimator
- Freedom of Information Request Cost Calculator
- Non-Compete Clause Value Estimator
Environment
19 calculatorsWaste, packaging weight and emissions estimates, with the working shown.
- Food Waste Calculator
- Per Capita Emissions Calculator
- Grid Carbon Intensity Calculator
- Paper Straw vs Plastic Straw Impact Calculator
Gaming
19 calculatorsBuild and progression maths for the games I actually play.
- Boss Fight Damage Requirement Calculator
- Mythic Dungeon Keystone Level Calculator
- PvP Rating Floor Calculator
- Alliance War Points Calculator
How the numbers are made
No black box. This is the whole method, and it applies to every page on the site.
- Formulas from published sourcesStandards, carrier rules, official documentation and textbooks. Where an answer depends on a convention, or on a year, the assumption is printed on the tool page.
- Checked against a worked exampleEach calculator is run against an example worked out by hand, and that example is kept so a later change can be re-checked against the same case.
- Reference values moveRules, thresholds and published indices change over time. When one changes and I notice, the page is updated and the date is recorded on this site.
- Corrections are the pointEmail what looks wrong and I will re-derive the formula, fix the page and say what changed. A correction is a better outcome than a confident wrong answer.
Before you use a number
Four habits that catch most of the mistakes these tools produce.
Keep the units consistent
Most wrong answers are unit errors rather than formula errors. Mixing kilograms with pounds, or cubic metres with cubic feet, gives a figure that looks plausible and is far out. Write the unit next to every value you enter, and check the unit the tool is expecting before you press anything.
Round at the end
Rounding halfway through a multi-step calculation drifts. Carry the full value through the working and round once, at the end, to the precision the decision actually needs. A freight class or a container count is a whole number. A cooking ratio is not.
Run a case you already know
If you know the answer to one example, put that in first. A calculator that reproduces the case you can verify is one you can reasonably use on the case you cannot.
Read the assumption line
Every tool page lists what the formula assumes about your situation. If an assumption does not match your case, the result does not apply to it, however precise the number looks on screen.
Guides
Longer write-ups for the calculations that need context, a worked case, or a rule explained properly.
- Freight density and LTL reclassificationWhy density decides the class, and how a shipment ends up reclassified.
- FCL shipping cost worksheetA full container priced from a real China to US lane, line item by line item.
- Customer support cost per ticketCost per ticket split by channel and by how difficult the case is.
- Cloudflare bandwidth figures, and why they misleadWhat the dashboard counts, and why the reduction it reports is not what you get.
Missing something?
Tools get added when somebody actually asks for one. Send the calculation you need, or a result that looked wrong, and I will work through it.
None of this is professional advice, and I do not hold a licence in the fields these tools touch. Every result depends on the figures you type in. The disclaimer and the story behind the site explain the rest.