Six equipment calculators: select the calculation

Choose the quantity you need to calculate: generator demand, mixing oil, chain measurements, cord voltage drop, nozzle number or a covered production-code interpretation. Each tool shows its inputs and worked arithmetic. Verify the actual equipment specifications before acting on a result.

Choose a calculator

Calculation and approval are different steps

Result and verification
Tool	Verify afterward
Generator demand	Actual starting VA, concurrent starts, fuel and outlet limits
Fuel mix	Equipment-specified ratio and oil
Chain measurements	Approved family, bar, sprocket and kickback classification
Cord voltage drop	Complete cord and connector current ratings
Nozzle number	Approved orifice, angle, connector and pressure
Production code	Correct plate, model and covered format / era

For example, a 0.750-inch span across three rivets gives 0.375-inch pitch. That arithmetic does not distinguish 3/8-inch low-profile from full-size chain. Likewise, a voltage-drop result for 12 AWG cannot establish the rating of an unidentified cord assembly.

Results and saved inputs

With JavaScript, Calculate runs on the page. Without it, a submitted form receives a result from this site.

The response is not cached or stored as a profile. Optional My Equipment saving keeps entered values in this browser.

Version 1.1.0 identifies the reviewed formula behavior. A saved input can still be stale or belong to a different job: check units and conditions each time. See privacy details for local storage, contact and recall-search requests.

Tools

Calculators that show their working

These six tools each answer one question that owners get wrong in a predictable way, and each one shows its formula, its assumptions and a worked example on the same page as the answer. They are deterministic: the same inputs always produce the same result, there is no model guessing at anything, and each carries a version number so a result you noted last year still means what it meant then. They also refuse bad input instead of correcting it: enter a chain span in millimeters where inches are expected and you get an error naming the field, rather than a plausible-looking answer computed from a number that was quietly adjusted.

A calculator that hides that adjustment is worse than one that refuses.

The form, the methodology and the tests all come from one versioned definition, and a calculator whose vectors fail is not published at all.

CA-01
Generator sizing

Turns a load list into the two numbers a generator is sold on, continuous running watts and starting watts, and shows which of them decides your purchase.

Four inputs · two ratings out
CA-02
Two-stroke fuel mix

Oil quantity for any ratio and any volume, in both US fluid ounces and millilitres, with the exact figure rather than the rounded one printed on a bottle.

Three inputs · both unit systems
CA-03
Chainsaw chain identifier

Three measurements taken off the saw become the specification a chain is sold by. It also tells you when a measurement matches no standard pitch, rather than rounding quietly.

Three inputs · refuses to guess
CA-04
Generator extension cord gauge

The smallest copper cord that carries the current over the distance without dropping more voltage than you allow, checked against the cord’s own current rating as well.

Four inputs · two tests, both must pass
CA-05
Pressure washer nozzle size

The orifice size that matches a machine’s flow and working pressure, plus the cleaning-units figure that lets two machines be compared.

Two inputs · size and cleaning units
CA-06
Serial number date decoder

Applies a manufacturer’s own published serial-number or date-code convention, brand by brand, and says plainly when no such convention is public rather than guessing.

Nine brands · decodes six, declines three

How these are built

The six calculators show their input units, formulas and worked examples alongside the result. Test a measured value rather than substituting a larger advertised rating: pump flow is not nozzle orifice, running watts are not starting watts, and nominal battery voltage is not stored energy. Use the named model’s limit when a published specification governs the choice.

Inputs are validated rather than corrected. Enter a chain measurement in millimeters where inches are expected, or a pressure below anything a real machine produces, and you get an error naming the field, not a result computed from a number quietly nudged into range. That distinction matters more than it sounds, because a tool that turns an impossible input into a plausible output gives you no signal that anything happened.

Three kinds of number, labeled differently

What kind of authority each figure in these tools carries.
Kind	Worked example	How much weight it deserves
Specified	The copper conductor resistances in the cord calculator, from the National Electrical Code conductor-properties table.	It is the published value. The result is that value applied to your numbers.
Convention	The nozzle-size definition, flow at 4,000 PSI, and the four standard chain pitches.	Universally used across the industry, and not mandated by anyone. Reliable, but the machine in front of you wins.
Planning assumption	The motor start-factor multipliers in the generator calculator, and the 3% and 5% voltage-drop targets.	Chosen so the tool has somewhere sensible to start. Where you have a measured figure, locked-rotor amps from a nameplate, use it instead.

What a result is not

None of these is a certification, a quote, an electrical design or a legal opinion. They do not know the condition of your machine, the state of your cords, the temperature you are working in or what a previous owner changed.

Where a result and a plate on the equipment disagree, the plate wins. Where it disagrees with your manual, the manual wins: it describes a machine we cannot see. And where a calculation touches a building's wiring, an electrician's judgement governs, not ours.

National Electrical Code, Chapter 9, Table 8: Conductor Properties (DC resistance at 75 °C) : National Fire Protection Association, NFPA 70, Chapter 9, Table 8.
Standard Specification for Automotive Spark-Ignition Engine Fuel : ASTM International, ASTM D4814.
Outdoor Power Equipment, Internal Combustion Engine-Powered Hand-Held Chain Saws, Safety and Environmental Requirements: Outdoor Power Equipment Institute / ANSI, ANSI/OPEI B175.1-2012 (with A1-2014).

Calculators that show their working: questions

Are these calculators accurate and where do the numbers come from?

A result depends on the stated formula and input range. Published standards and planning assumptions are distinguished in the explanation, and a measured value can replace an assumption when available. Compare the printed example with the machine’s plate, manual or component marking before treating a numerical result as a purchase or operating instruction.

Do these calculators send my data anywhere?

The usual calculator runs in your browser. If you submit the fallback form, its entered values are sent to this site’s calculation endpoint and the server returns the result.

No account is required for either route. The privacy policy explains request processing; browser calculation and submitting a form are different data flows.

Saved machine records and saved calculator values use this browser’s local storage through the optional save feature; see My Equipment. Those records are separate from a fallback calculation request sent to the server.

With JavaScript unavailable, the form can still submit supported inputs and return an HTML result. The printed formula, assumptions and worked examples also let you check the arithmetic by hand.

Can a calculator remember my numbers for next time?

Yes, if you choose to. Every result offers a "Save these numbers" prompt that stores them, in this browser only, against a machine you name at My Equipment. The next time you open a calculator that asks for one of the same figures, it offers to prefill it from what you saved.

Skip the prompt and nothing changes: the calculator behaves exactly as it always has.

What are the three kinds of number these calculators use?

Specified values, taken directly from a published standard, such as the National Electrical Code conductor resistances in the cord calculator; conventions, universally used across the industry but not mandated by anyone, such as the four standard chain pitches; and planning assumptions, chosen so the tool has somewhere sensible to start, such as the motor start-factor multipliers in the generator calculator. Each is labeled differently because each deserves a different amount of trust against a measured figure from your own equipment.

Are any of these six calculators a certification, a quote, or a legal opinion?

No: none of the six is a certification, a quote, an electrical design, or a legal opinion. Each is deterministic arithmetic against a stated formula, useful for planning a purchase or a task, but not a substitute for a licensed professional's judgement where one is legally or practically required.

Which calculator should I use first if I'm buying a generator?

Generator sizing, to get your running-watt and starting-watt totals from your own load list: then the extension cord calculator, since the cord you'll need depends on the load and distance you settle on once the generator is sized.

Do these calculators account for altitude, temperature, or other environmental factors?

Not directly: each formula works from the inputs described on its own page (load, ratio, measurement, current, or flow and pressure), and none adjusts for altitude, ambient temperature, or other site conditions. Where those factors matter for a specific machine, the manufacturer's own documentation is the source to check.

Do I need to create an account or provide an email to use these calculators?

None of the six tools requires an account, email address or registration to calculate a result. Browser calculation can run locally, while the fallback form sends its inputs to this site’s server.

Saving values in My Equipment is optional and uses browser storage. Read the privacy policy for request-processing details rather than assuming every interaction has the same data flow.