Ham Radio

Translate one explicitly ordered four-band resistor marking, preserve its source and orientation, and optionally compare a complete measured resistance interval without identifying or approving the component.

Calculate equivalent resistance for two resistors in series or parallel. Free series and parallel resistance calculator for circuit design, hobby electronics.

Calculate output voltage from a two-resistor voltage divider. Free voltage divider calculator for circuit design, hobby electronics, and prototyping.

Size the series resistor for safe LED operation. Free led current limiting resistor calculator for circuit design, hobby electronics, and prototyping.

Estimate covered in-network costs from confirmed plan terms, or reconcile EOB patient responsibility with payments, credits and a provider statement.

Apply entered in-network deductible, coinsurance, copays, and out-of-pocket maximum terms to an entered allowed-charge scenario, plus premiums.

Calculate a user-entered heart-rate-reserve percentage range with the Tanaka age-estimated maximum. Shows formula and limits; never prescribes training zones.

Budget actual prescription fill payments and compare two pharmacy quotes by supply days, full-fill costs and fees. Save locally and export assumptions.

Calculate dipole and quarter-wave vertical antenna lengths from frequency. Free online ham radio calculator with instant, accurate results.

Calculate standing wave ratio from forward and reflected power. Free online ham radio calculator with instant, accurate results.

Calculate half-wave dipole and quarter-wave vertical antenna element length from frequency. Includes velocity factor correction for wire type.

Calculate reflection coefficient and L-network Q for impedance matching. Free online ham radio calculator with instant, accurate results.

Convert antenna gain between dBi and dBd and estimate beamwidth. Free online ham radio calculator with instant, accurate results.

Calculate standard or Farnsworth Morse timing, including every gap. Time actual text and repeated copies, choose the final gap, and export a complete report.

Convert frequency to wavelength in meters and feet. Essential ham radio tool for planning, budgeting, and project optimization.

Calculate voltage, current, power, and impedance relationships. Free online ham radio calculator with instant, accurate results.

Convert between watts, milliwatts, dBm, and dBW. Essential ham radio tool for planning, budgeting, and project optimization.

Convert RF power between watts, dBm, and dBW. Calculate power density and link budget components for ham radio and wireless.

Calculate DC current draw from RF output power and supply voltage. Free online ham radio calculator with instant, accurate results.

Estimate coax cable attenuation at frequency and length. Free online ham radio calculator with instant, accurate results.

Calculate coaxial cable RF signal loss in dB from cable type, run length, and frequency. Estimate transmit power delivered to your antenna.

Calculate RF link budget from transmit power, gains, and losses. Free online ham radio calculator with instant, accurate results.

Estimate VHF/UHF repeater coverage from antenna heights and ERP. Free online ham radio calculator with instant, accurate results.

Calculate free-space path loss using the Friis transmission equation. Free online ham radio calculator with instant, accurate results.

Calculate Effective Isotropic Radiated Power from TX power and antenna gain. Free online ham radio calculator with instant, accurate results.

Calculate SNR in dB from signal and noise power levels. Free online ham radio calculator with instant, accurate results.

Estimate HF propagation distance for a band and solar conditions. Free online ham radio calculator with instant, accurate results.

Calculate filter cutoff frequency for RC or LC designs. Free online ham radio calculator with instant, accurate results.

Estimate occupied bandwidth by modulation type and parameters. Free online ham radio calculator with instant, accurate results.