All free tools

Every free calculator, checker and planner on UnitedTechs, grouped by field. Tools that apply a rule or standard link to the official source. No sign-up needed.

Ham Radio

• HF Band Conditions
  Live HF band conditions from NOAA Space Weather Prediction Center and N0NBH / HAMQSL.com. Updated about once an hour. Free tool from UnitedTechs.
• Band privilege charts
  Interactive FCC band privilege chart for Technician, General, and Extra — frequencies and modes from 47 CFR §§ 97.301 and 97.305.
• License exam practice
  Free Technician, General, and Extra amateur radio exam practice from the public-domain NCVEC question pools. Progress stays in your browser only.
• Station ID timer
  Free browser station ID timer for any radio: a 10-minute countdown based on 47 CFR 97.119(a), with reset and an optional beep.
• Is IDMinder right for my station?
  A quick in-browser checker: does your station fit IDMinder for the Icom IC-7760 (Windows 10/11, USB, Voice TX Memories)?
• Can I transmit here?
  Type a frequency, pick your license class and mode, and see if you may transmit there, with the band segment, power limit and the 47 CFR 97.301/97.305 rule cited.
• Antenna Length Calculator
  Free ham antenna length calculator for half-wave dipoles and quarter-wave verticals, from the speed of light with the ARRL 468/f check, leg lengths and trim guidance.
• SWR to Return Loss Calculator
  Free SWR, return loss and reflection coefficient converter with mismatch loss and reflected power, with formulas and steps shown.
• Coax Loss Calculator
  Free coax loss calculator: scales your cable datasheet loss to your frequency, adds the extra loss from SWR, and shows the power reaching the antenna.
• RF exposure (MPE) calculator
  Free ham RF exposure (MPE) calculator: safe distance for neighbors and household, duty factor and time averaging, and the 1.1307 exemption check.
• Station ID builder
  Free ham station ID builder: your exact ID with /AG, /AE, special event or reciprocal indicators, phonetics or Morse, and when to ID under 47 CFR 97.119.

Drones

• Part 107 practice test
  Free FAA Part 107 practice questions by topic or a 60-question mock exam, with shuffled answers and cited explanations. Progress stays in your browser.
• Pre-flight checklist
  A printable drone pre-flight checklist built from 14 CFR 107.49 and related Part 107 sections, with FAA and eCFR links.
• Drone Flight Time Calculator
  Free drone flight time estimator from battery capacity and average current or power, with usable capacity and a landing reserve. Shows the formula and every step.
• Part 107 Limits Checker
  Free Part 107 limits checker: enter planned altitude, groundspeed, visibility, cloud clearance and weight; see each limit with its 14 CFR 107 section.
• Remote ID and registration checker
  Four questions: must your drone be registered and broadcast Remote ID, and which way to comply (standard Remote ID, a module or a FRIA). Cites 14 CFR 48 and 89.

Industrial & Electricians

• Electrician License Path Finder
  Compare electrician license levels, hours, exams and renewal rules by state, each fact linked to the official state board page. 26 states.
• Voltage Drop and Wire Size Calculator
  Free voltage drop calculator for copper and aluminum, single-phase, three-phase or DC. Every step shown, smallest size that meets your target, NEC sections cited.
• Conduit Fill Calculator
  Free conduit fill calculator: applies the NEC Chapter 9 Table 1 fill percentages and nipple rule, shows every step, and tells you how many more conductors fit.
• Ohm's Law and Power Calculator
  Free Ohm's law calculator: enter any two of volts, amps, ohms or watts and get the other two, with the formula and each step shown.
• Three-phase power calculator
  Free three-phase power calculator: amps to kW, kVA and kVAR, kW or kVA to amps, and motor hp to input kW, with power factor and every step shown.

IT & Networking

• Help-Desk Triage Card Builder
  Turn a symptom into an ordered troubleshooting checklist with built-in commands, mark each step's result, and copy a ready ticket note for the next tier.
• Subnet / CIDR Calculator
  Free IPv4 subnet calculator: network, broadcast, mask, wildcard and usable host range (/31 and /32 handled), address type, and a splitter for smaller subnets.
• VLSM subnet planner
  Free VLSM calculator: list subnets and host counts; get each network, mask, usable range and broadcast with the bit math shown. /31 links (RFC 3021) optional.
• Fiber optic loss budget calculator
  Free fiber loss budget: fiber, connections and splices at typical and TIA-568 maximum values, power margin from your optics and a pass/fail test limit.

Medical & Biomed

• CBET Path Finder
  Check CBET exam eligibility in seconds: full status vs candidate status by education and BMET experience, from AAMI's official CBET requirements.
• AEM eligibility check
  Can this equipment go on an alternate equipment management (AEM) program? Screen it against CMS S&C 14-07-Hospital and print the documentation checklist.
• Electrical Safety Test Record Sheet
  Free electrical safety test record sheet for biomed techs: enter your facility's limits and measured values, get pass/fail, print, CSV and history.
• FDA medical device recall quick-check
  Search FDA medical device recall records by product, firm or recall number. Free, from openFDA public data, with the recall class where FDA has published it.
• FDA device classification & product code lookup
  Look up an FDA medical device product code, device class, regulation number and submission type. Free, from openFDA public data, linked to FDA records.

Clinical Lab

• Lab Career & State Licensure Path Finder
  Does your state license clinical lab personnel, and which CLIA testing rules does your education meet? Each state fact links to the official page.

HVAC/R

• A2L Refrigerant Transition Checker
  New install, service or replacement? A cited checklist for R-410A, R-22, R-32 and R-454B jobs: 608 rules, the GWP 700 limit, no A2L drop-ins, codes.
• EPA 608 Type Picker
  Check the equipment you work on and see which EPA Section 608 certification you need: Core plus Type I, II or III, or Universal. Cited to 40 CFR 82.161.

Automotive

• xEV High-Voltage Safety Checklist
  Printable pre-work checklist for hybrid and EV high-voltage service: de-energize, lockout, live-dead-live check, one-hand rule. Cited to ASE and OSHA.
• ASE certification cost & path planner
  Pick your ASE tests and see the total fees, recertification cap, prerequisites and work experience you need. Every number copied from ASE.

All fields

• Credential Renewal Calendar
  Track tech credential renewals in one place: FAA Part 107, FCC amateur, ASE, AAMI CBET and more. Rules cited to official pages; .ics calendar export.