Free Tools
Trade Exam Calculators
Free reference tools for every trade — the same calculators built into our exam prep apps, available free on the web.
Voltage Drop Calculator
NEC-compliant voltage drop for single and three-phase circuits. Checks compliance with NEC 210.19(A) for any wire gauge and run length.
NEC Wire Size Recommender
Enter load, distance, and voltage — get the minimum AWG or MCM that keeps voltage drop within NEC limits. Full table from 14 AWG to 500 MCM.
Ohm's Law Calculator
Solve for voltage, current, resistance, or power from any two known values. Includes all 12 Ohm's Law formulas.
Conduit Fill Calculator
Calculate NEC conduit fill percentage. Supports EMT, IMC, RMC, and PVC. THHN/THWN wires #14–4/0. Instant compliance check.
OSHA Fine Calculator
Estimate OSHA penalty amounts by violation type, gravity, and employer size. Updated with 2024 penalty limits.
Fire Alarm Battery Calculator
Calculate minimum battery Ah per NFPA 72 §10.6.7. Standby + alarm current with 20% derating factor. Occupancy presets for residential, commercial, high-rise, and healthcare.
Backflow PSID Calculator
Enter field test PSID readings for DC, RP, PVB, or SVB assemblies — instant pass/fail per USC and AWWA M14 criteria. Includes quick-reference threshold table for all assembly types.
NEC Box Fill Calculator
Calculate minimum cubic-inch box volume per NEC 314.16(B). Enter conductors by AWG, devices, grounding conductors, and clamps — see required fill and matching standard box sizes instantly.
EMT Drug Dose Calculator
Practice weight-based drug calculations for NREMT exam. Covers epinephrine, adenosine, amiodarone, naloxone, and more.
Hazmat Placard Lookup
Enter any UN number (e.g. UN1203) and get the DOT placard class, proper shipping name, packing group, and hazard description instantly.
Crane Load Ratio Calculator
Calculate load-to-capacity ratio and rigging weight. Know your working load limits before you lift.
Refrigerant Charge Calculator
Estimate refrigerant charge by system tonnage and refrigerant type. Covers R-410A, R-22, R-32, and R-134a.
Real Estate Commission Calculator
Calculate gross commission, agent split, and net proceeds for any home sale. Essential for real estate license exam math questions.
Glasgow Coma Scale (GCS) Calculator
Score a patient's GCS from eye opening, verbal, and motor responses. Instant severity classification — minor, moderate, or severe TBI.
OSHA Fall Clearance Calculator
Calculate total fall clearance distance for shock-absorbing lanyards and SRLs per OSHA 1926.502. Pass/fail based on anchor height and lanyard type.
Pipe DFU Calculator
Calculate total drainage fixture units and minimum drain pipe size per IPC 2021 Table 710.1. Select fixtures and quantities for instant pipe sizing.
Phlebotomy Order of Draw
Interactive blood draw tube sequence per CLSI GP41. Click any tube for additive, purpose, common tests, and required mix inversions.
Pool Chemical Calculator
Calculate pool volume in gallons, free chlorine dosing (liquid or granular), and pH adjustment with muriatic acid or soda ash. CPO and AFO exam prep.
Coinsurance Calculator
Calculate insurance payouts, coinsurance penalties, and out-of-pocket costs using the standard P&C formula. Includes step-by-step exam breakdown. Essential for the Insurance P&C license exam.
NMLS Mortgage Calculator
Four calculators in one: PITI monthly payment, front/back-end DTI ratios, LTV and PMI thresholds, and a full amortization schedule. The exact mortgage math scenarios on the NMLS SAFE Act exam.
Discount Points & Buydown Calculator
Compute the up-front cost of discount points (1 point = 1% of the loan) and the cost of a 2-1 or 3-2-1 temporary rate buydown. Permanent vs temporary rate reduction — a core NMLS SAFE Act exam distinction.
Per-Diem Interest Calculator
Calculate daily and prepaid mortgage interest collected at closing, using both the 360-day and 365-day methods. The exact per-diem math tested on the NMLS SAFE Act exam.
ARM Adjustment Calculator
Find the fully-indexed rate (index + margin) and apply initial, periodic, and lifetime caps to determine an adjustable-rate mortgage's new rate at adjustment. Core ARM math for the NMLS exam.
TRID Timeline Calculator
Compute TRID disclosure deadlines: Loan Estimate (3 business days after application), Closing Disclosure (3 before consummation), the 7-day waiting period, and the 3-day right of rescission on refinances.
One-Rep Max Calculator
Estimate your 1-rep max from any set with the Epley and Brzycki formulas, plus training-load percentages. Core programming math for the NASM, ACE, and ISSA personal trainer exams.
GRM & Cap Rate Calculator
Compute gross rent multiplier, capitalization rate, and implied value with the income-approach formulas. Essential math for the real estate appraisal exam.
Broker Math Calculator
Total commission, seller's net proceeds, and the net-to-list price needed to net a target. The high-frequency math on the real estate broker license exam.
Forklift Load Center Calculator
See how a longer load center derates a truck's safe capacity and check a load against limits. A core stability concept on the OSHA forklift certification exam.
Earned Value (EVM) Calculator
Compute CPI, SPI, CV, SV, EAC, ETC, and TCPI from BAC, PV, EV, and AC — the core earned-value formulas tested on the PMP and CAPM exams.
Process Sigma / DPMO Calculator
Convert defects, units, and opportunities into DPMO, yield, and a process sigma level (with the 1.5σ shift). A staple of Six Sigma Green and Black Belt exams.
Pharmacy Dosage & IV Rate Calculator
Weight-based dosing, IV pump mL/hr, drip rate gtt/min, and days supply — the everyday pharmacy math on the PTCB/PTCE exam.
Markup vs Margin Calculator
Convert between markup and margin from cost and price — the pricing math contractors miss on the business & law exam.
Hair Color Developer Ratio Calculator
Mix color to developer by ratio (1:1, 1:2, and more) and get exact developer and total amounts for the cosmetology exam and salon.
Engine Displacement Calculator
Calculate engine displacement in CID, liters, and cc from bore, stroke, and cylinder count — a core ASE engine-measurement concept.
Weld Heat Input Calculator
Weld heat input in kJ/in and kJ/mm from amperage, voltage, and travel speed — a Part B calculation on the AWS CWI exam.
Weld Symbol Decoder
Build any AWS A2.4 welding symbol and read it in plain English — arrow side vs. other side, dimensions, contour, and supplementary symbols for the CWI exam.
Fillet Weld Size Calculator
Convert fillet weld leg size to theoretical throat and back — equal and unequal legs. The leg-vs-throat relationship the AWS CWI exam tests.
Carbon Equivalent Calculator
IIW carbon equivalent from steel chemistry with weldability and preheat-risk guidance — the metallurgy behind CWI preheat questions.
Bridge Cam Gauge Guide
What a bridge cam gauge measures — prep angle, reinforcement, undercut, fillet leg and throat, misalignment — and how to read each. A CWI Part B reference.
Weld Discontinuity Map
Interactive weld cross-section showing where porosity, undercut, cracks, and other discontinuities occur — with causes and how each is inspected.
NDE Methods Compared
VT, PT, MT, RT, and UT side by side — what each detects, material limits, cost, and records. The NDE trade-offs the CWI exam tests.
Density Altitude Calculator
Density altitude from field elevation, altimeter setting, and temperature — a performance concept for FAA Part 107 remote pilots.
Pesticide Mix Rate Calculator
Total product and product-per-tank from application rate and area — the mixing and calibration math on the pesticide applicator exam.
Chlorine Dosage Calculator
Chlorine feed rate in lbs/day (the pounds formula) and dose from demand plus residual — core math for the water treatment operator exam.
Coming Soon
Cooling Load Timer
2-stage cooling timer based on FDA requirements — tracks 135°F→70°F in 2 hrs and 70°F→41°F in 4 hrs for food safety compliance.
New Tools
Get notified when new tools launch
Drop your email and we'll let you know the moment a new trade calculator goes live.
Don’t see your trade?
Tell us what certification you’re studying for and we’ll notify you when we launch a new app.