44 engineering calculators, from cable sizing to arc flash, with reports styled your way
Cables, fault levels, arc flash, motors, transformers, earthing, pumps and conveyors, to AS/NZS, IEEE, NEC and CEC. Results update as you type, every equation prints with your numbers, and the PDF comes out in any of eight report styles or your own stylesheet, A5 to A3, portrait or landscape. Free to use, no account needed. Sign in to save and export.
No sign-up to calculate Edit any input and the whole report updates. Sign in only when you want to keep it.
- calculate44 calculators
- category9 categories
- lock_openFree, no account needed
- fact_checkValidated against published worked examples
- AS/NZS 3008.1.1:2017
- AS/NZS 3000:2018
- IEEE 1584-2018
- IEEE Std 80
- IEEE 519
- NEC 2020
- CEC 2024 / CSA C22.1:24
- IEC 62305
- IEC 60909
- AS/NZS 60076
How it works
From a blank calculator to a report you can hand over, in three steps. The first two need no account.
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Step 01
Pick a calculator
Choose from the catalogue below and it opens straight away, no sign-up, with sensible defaults already filled in.
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Step 02
Edit the inputs, the report updates live
Change a load, a length or an installation method and every equation, check and result on the page recalculates as you type.
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Step 03
Sign in to save and export
A free account keeps the calculation in your library with its calc number and revision, and exports it as PDF or Excel.
The calculators
Every calculator opens free, with no account. Click one to start.
Cable Sizing 15
- Cable Voltage Drop (AC3) Calculate voltage drop for three-phase cable runs per AS/NZS 3008.1.1.2017 standard
- Motor Cable Sizing Comprehensive motor cable sizing with four critical checks (CCC, VD, SC, EFL)
- Lighting Circuit Voltage Drop Calculate voltage drop in parallel-connected lighting circuits with sequential cable runs
- AC Light Circuit Voltage Drop Calculate voltage drop in parallel-connected single-phase AC lighting circuits with cumulative analysis
- DC Cable Sizing Calculator Calculate conductor size and voltage drop for DC cables in solar PV, battery, and DC distribution systems
- HV Cable Sizing Calculator Three-phase high voltage cable sizing with Nexans Olex data (3.3kV-33kV)
- NEC Cable Sizing Comprehensive NEC cable sizing with continuous load, ambient, bundling corrections, and voltage drop
- CEC 2024 Canadian Cable Sizing Balanced LV three-phase general-load and motor cable sizing to CSA C22.1:24
- Load Cable Sizing Comprehensive load cable sizing with four critical checks (CCC, VD, SC, EFL)
- Cable Size Range Range of standard cable sizes that conform for a given load and installation (CCC, VD, SC, EFL, overload coor…
- Cable Permissible Load Largest load and protective device a cable may carry for its installation (CCC, VD, SC, EFL, overload coordin…
- Motor Cable Selection Chart Max cable length and loading chart across motor ratings and cable sizes for one installation (AS/NZS 3008.1.1…
- Load Cable Sizing (1-Phase) Single-phase load cable sizing with four critical checks (CCC, VD, SC, EFL)
- Motor Cable Sizing (1-Phase) Single-phase motor cable sizing with four critical checks (CCC, VD, SC, EFL)
- Cable Volt Drop Table Maximum cable length matrix based on running voltage drop per AS3008
Power & Voltage 3
- Three-Phase V-I-P Calculator Calculate voltage, current, power, and impedance for 3-phase electrical systems
- Single-Phase V-I-P Calculator Calculate voltage, current, power, and impedance for single-phase electrical systems
- Power-Motor Calculator (AC3) Calculate electrical parameters for three-phase AC motors including current, apparent power, reactive power, …
Protection & Fault Analysis 8
- Earth Fault Loop Calculator Calculate earth fault loop impedance for electrical safety analysis and protection
- Arc Flash Hazard (IEEE 1584-2018) Calculate arcing current, incident energy, arc flash boundary, and PPE requirements
- Short-Circuit Current Three-phase short-circuit current calculations using Bussmann point-to-point method
- NEC Short Circuit Analysis Calculate fault currents and equipment interrupting ratings per NEC 110.9, 110.10, and 408.6
- CB Overload Protection Overload protection coordination per AS/NZS 3008.1 Clause 2.5.3
- Earth Fault Loop Impedance Calculate Zs including source impedance, cable impedance and standard checks
- Lightning Risk Assessment Lightning risk assessment per IEC 62305-2 for R1 (loss of human life)
- Protection Coordination TCC Time-Current Characteristic curve generation and coordination analysis
Motors & Drives 2
Equipment Sizing 5
- CT Selection & Sizing Current Transformer selection and sizing with burden, saturation, and ALF checks
- Generator Sizing Calculator Calculate required generator capacity based on connected loads, diversity factors, and motor starting require…
- MV Capacitor Bank Sizing Comprehensive MV capacitor bank sizing with power factor correction, harmonic analysis, reactor design, and e…
- UPS Selection & Battery Sizing Size UPS systems and battery banks for backup power with runtime calculations
- Transformer Sizing & Specification Comprehensive transformer sizing and specification per AS/NZS 60076
Load & Distribution 5
- Maximum Demand Calculator Calculate maximum demand for residential electrical installations per AS/NZS 3000:2018
- Commercial Panel Maximum Demand Calculate maximum demand for commercial/industrial panels per AS/NZS 3000 Table C2/C3
- Load Flow Analysis (Gauss-Seidel) Multi-bus power system load flow analysis using Gauss-Seidel iterative method
- NEC Distribution Panel Sizing Size three-phase distribution panels per NEC Article 220, 430, and 310 standards
- Switchroom Heat Load Calculate HVAC cooling requirements for switchrooms and control buildings
Earthing 2
Mechanical 3
- Positive Displacement Pump Calculator Calculate duty point and suction safety for reciprocating positive displacement pumps
- Centrifugal Pump System Calculate TDH, NPSH, and slurry settling for pump selection
- Belt Conveyor Design Complete mechanical design for belt conveyors: capacity, belt sizing, tensions, power, and drive selection
Inspection checksheets and forms, built on an A4 page
Drag widgets onto A4 pages to build inspection checklists, test records and data collection sheets. Share a link so the sheet can be filled in on site from a phone, keep every submission, and print the same layout to PDF. Open and print the templates without an account; sign in to save your own.
- dashboard_customize Build a checksheet Checklists, yes/no lists, input lists, tables, images, metrics and charts, placed on one or many pages.
- phone_android Fill in from any device Every checksheet has a form link that opens on a phone or tablet, so it can be completed in the field.
- inbox Track submissions Completed sheets are kept with who filled them in and when, and can be compared side by side.
- widgets Your own widget templates Define reusable widget types for your team and share finished checksheets as public designs.
What the report looks like
First pages of real reports, straight from the PDF export. Every equation is printed with your numbers substituted, so a reviewer can follow the working.
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Load cable sizing to AS/NZS 3008.1.1 — A4 portrait, standard style 1 / 4 chevron_right -
The same calculation in A4 landscape with multi-column layout 2 / 4 chevron_left chevron_right -
Cable size range — a results table across every conductor size 3 / 4 chevron_left chevron_right -
Cable permissible load — maximum load against length for a chosen cable 4 / 4 chevron_left
Report and output features
- functions Equations with your numbersEvery formula is printed with the values substituted, not just the answer.
- picture_as_pdf PDF in any page sizeA5, A4, A3, Letter and Legal, portrait or landscape, one to six columns.
- palette Eight built-in styles, plus your ownPick a report style or write your own stylesheet.
- table_view Excel for every calculatorInputs, intermediate values and results as a workbook you can keep working in.
- show_chart SVG diagramsPower triangle, phasor, time–current curves, torque–speed, load-flow and conveyor profile, drawn from your inputs.
- draw Signatures, logo and QR codePrepared-by and checked-by signatures, your company logo and a QR code back to the calculation.
- tag Calc number, tag, revision and projectThe document-control fields a reviewer expects, on every page.
Deterministic engines, not a model's guess
Every calculator is a conventional engineering engine: the same inputs always give the same answer, with the clause and table it relied on named in the report. There is no AI between your inputs and the result.
The engines are validated against published worked examples from the standards and textbooks, and the validation report lists every case with its expected and computed values.
The same calculators, as MCP tools
Claude, ChatGPT, Cursor and any other MCP client can call the same deterministic engines. Every result comes back with its governing constraint, checks, clause references, assumptions and hashes, so an agent's answer can be reproduced and checked.
500 calls/day with a free key. Endpoint http://fast.engineer/mcp.
Claude Code
claude mcp add --transport http fast-engineer http://fast.engineer/mcpOther clients, the anonymous tier, agent keys and the signed-in workspace are on the agents page.
Human certification of AI work
Post your calculation or document, whether you or an agent produced it, and get fixed-fee quotes from registered Australian engineers to review it, take it into responsible charge and sign it off. Agents request it over MCP; people use the web wizard. Same engineers, same documented review protocol, same signed package.
The reviewer panel is being assembled now, and requests posted today are matched as registered engineers come on board.
The agent's tool chain
fe_market_review_request_create— open the request with its AI-provenance declarationfe_market_document_add— attach the calculations and drawingsfe_market_request_submit— registered engineers for that state and discipline quotefe_market_certification_get— fetch the signed certification package and its hash chain
- ruleA documented review, not a stamp. A review-time floor, mandatory checklist items and attached calculation checks.
- badgeRegistered for the project's state. RPEQ, NSW DBP, VIC PER, ACT, WA DEMIRS, NER / CPEng, with PI insurance tracked.
- percent1% commission, plus payment processing at cost. The engineer quotes a fixed fee in AUD and keeps it, less the commission and the card fee passed through with no markup.
AI inside the tools is optional
The calculators never use AI. Where a tool offers an AI assist, it is off until you turn it on, and you can bring your own API keys so the billing is yours.
More on fast.engineer
- architecture Drawing digitization PDF, CAD and scanned drawings into symbols, wiring and an editable diagram.
- verified Sign-off marketplace Registered Australian engineers quoting fixed fees for review and certification.
- terminal MCP server, technical page Endpoints, the live tool list and copy-paste client configuration.
- menu_book Calculator help A worked example and the method behind every calculator.
Start calculating
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