Free calculators for RF & antenna work.
Dimension resonant elements, calculate transmission line losses, match VSWR impedances, and analyze link budgets without installing software.
Start with a tool engineers open most
Half-Wave Dipole Calculator
Calculate exact resonant element lengths, end-effect shortening factors, and velocity factor corrections for any wire or tubing center-fed dipole.
VSWR & Return Loss
Voltage standing wave ratio, reflection coefficients, and mismatch loss.
Coaxial Cable Attenuation
Cumulative decibel attenuation over line length and power transfer.
Free Space Path Loss (FSPL)
Geometric spreading attenuation and link budgets across frequencies.
Quarter-Wave Vertical Ground Plane
Resonant radiator lengths and ground radial wire dimensions.
Find Your Calculator
RF toolsSearch RF and antenna calculators by name, keyword, or engineering domain.
Frequency to Wavelength Calculator
Frequency to Wavelength Calculator
Quarter-Wave Calculator
Half-Wave Calculator
Full-Wave Calculator
Antenna Length Calculator
Electrical Length Calculator
Velocity Factor Calculator
Effective Wavelength Calculator
Resonant Frequency Calculator
Antenna Diameter Calculator
Element Length Correction Calculator
The RF Engineering Workflow: From Feedpoint to Far-Field
Professional wireless engineering requires connecting multiple mathematical stages. Use this guided pipeline to progress logically from raw antenna wire cut lengths to link budget margins.
Antenna Dimensioning & Physical Resonance
Convert operating radio frequency into physical element lengths. Calculate end-effect velocity factors, conductor diameters, and quarter-wave or half-wave resonant geometries.
Transmission Line Selection & Attenuation
Determine conductor dielectric properties, characteristic impedance, and cumulative decibel attenuation over line length to ensure maximum power transfer from transmitter to feedpoint.
Impedance Matching, VSWR & Power Reflection
Analyze terminal mismatch. Calculate voltage standing wave ratio, reflection coefficients, return loss, and actual radiated RF power versus reflected thermal losses.
Over-the-Air Wave Propagation & Path Loss
Calculate geometric path loss as electromagnetic waves spread through the atmosphere. Check Fresnel zone ellipsoid clearance to avoid terrain and building diffraction losses.
System Link Budget & Fade Margin Analysis
Aggregate transmitter output power, feedline losses, antenna gains, and free-space path attenuation against receiver sensitivity thresholds to ensure reliable packet reception.
Radiation Safety & FCC OET-65 MPE Compliance
Calculate power density in milliwatts per square centimeter at operational distances. Verify compliance with occupational and uncontrolled public electromagnetic exposure limits.
Start from the kind of calculation you need
Categorized topical hubs covering every phase of RF design, propagation physics, transmission lines, and satellite downlinks.
Antenna Calculators
Design and dimension resonant antennas: Dipoles, Verticals, Yagi-Uda arrays, J-Poles, Moxon rectangles, and magnetic loops.
RF Power & VSWR Calculators
Convert power between Watts, dBm, dBW, calculate Voltage Standing Wave Ratio (VSWR), return loss, and reflection coefficient.
Transmission Line Calculators
Compute coaxial cable attenuation, velocity factors, electrical length, characteristic impedance, and matching stubs.
Link Budget & Path Loss Calculators
Calculate Free Space Path Loss (FSPL), Friis transmission link budgets, fade margins, and receiver sensitivity.
RF Propagation Calculators
Determine radio horizon distance, Earth curvature clearance, 4/3 k-factor refraction, and 1st Fresnel zone clearance.
Wi-Fi Range & RF Calculators
Estimate indoor/outdoor Wi-Fi coverage across 2.4 GHz, 5 GHz, and 6 GHz bands, EIRP regulatory limits, and channel frequencies.
LoRa & LPWAN Calculators
LoRa link budget, spreading factor SNR thresholds, time-on-air, and range predictions for 868 MHz & 915 MHz deployments.
Cellular & 5G Calculators
3GPP path loss models, LTE/5G band frequencies, base station EIRP, and RSRP signal level estimation.
Satellite & Dish Calculators
Calculate parabolic reflector antenna gain, 3dB beamwidth, aperture efficiency, G/T ratio, and look angles.
RF Engineering & Safety Calculators
FCC OET-65 Maximum Permissible Exposure (MPE) safe distance evaluations and microstrip patch antenna PCB designs.
Complete RF Engineering Pillar Directory
Explore dedicated hubs organized across ten fundamental radio frequency and antenna calculation domains.
Antenna Calculators
Antenna calculators compute resonant element lengths, feed impedance, and gain for wire, vertical, and directive antennas from a given operating frequency. Enter frequency in MHz to receive physical dimensions in meters and feet, adjusted for velocity factor and end-effect capacitance.
RF Power & VSWR Calculators
RF power and VSWR calculators convert between power units (Watts, dBm, dBW) and compute voltage standing wave ratio, return loss, and reflection coefficient for radio frequency transmission systems.
Transmission Line Calculators
Transmission line calculators compute attenuation per unit length, characteristic impedance, velocity factor, and electrical length for coaxial cables, ladder lines, and striplines at a given frequency.
Link Budget & Path Loss Calculators
Link budget calculators determine whether a radio communication link is viable by summing transmitted power, antenna gains, free-space path losses, and comparing the total against receiver sensitivity and required fade margin.
RF Propagation Calculators
RF propagation calculators determine radio horizon distance, Fresnel zone clearance radius, and atmospheric refraction effects for point-to-point microwave and VHF/UHF wireless links.
Wi-Fi Range & RF Calculators
Wi-Fi RF calculators estimate indoor and outdoor coverage range, EIRP regulatory limits, and channel center frequencies for 802.11 a/b/g/n/ac/ax (Wi-Fi 4/5/6/6E) networks across 2.4 GHz, 5 GHz, and 6 GHz bands.
LoRa & LPWAN Calculators
LoRa calculators compute time-on-air for LoRaWAN packets, spreading factor sensitivity thresholds, and link budget range predictions for 868 MHz EU and 915 MHz US ISM band IoT deployments.
Cellular & 5G Calculators
Cellular RF calculators apply 3GPP-standard path loss models to estimate LTE and 5G NR coverage radius, base station EIRP limits, and RSRP received signal power at a given distance and frequency band.
Satellite & Dish Calculators
Satellite dish calculators compute parabolic reflector antenna gain, 3 dB half-power beamwidth, aperture efficiency, system G/T noise ratio, and azimuth/elevation look angles for geostationary and low Earth orbit links.
RF Engineering & Safety Calculators
RF safety and engineering calculators evaluate FCC OET-65 Maximum Permissible Exposure (MPE) safe distances for transmitting antennas and compute microstrip patch antenna physical dimensions for direct PCB fabrication.
Frequency Band Systems
Pre-configured, resonant antenna calculations tuned for popular amateur radio, satellite, LoRaWAN, Wi-Fi, and FPV bands.
VHF APT weather satellite reception from NOAA-15, NOAA-18, and NOAA-19 satellites.
Popular VHF amateur band for FM repeaters, simplex, and weak-signal SSB DXing.
Sub-GHz license-free telemetry, remote keyless entry, weather stations, and LoRa in Region 1.
UHF amateur radio band for FM repeaters, DMR, satellite uplinks, and mesh networking.
European standard license-exempt band for LoRaWAN, Sigfox, and smart metering IoT networks.
FCC Part 15 license-free ISM band for LoRaWAN, RFID, Meshtastic, and SCADA links in the Americas.
Commercial aircraft transponder broadcast frequency tracked by FlightAware / Flightradar24 receivers.
The 21cm astronomical radio window emitted by neutral interstellar hydrogen atoms across our galaxy.
Worldwide license-free band used for Wi-Fi 802.11b/g/n, Bluetooth, Zigbee, microwave ovens, and RC links.
High-throughput 5 GHz Wi-Fi channels and analog/digital drone FPV video transmitters.
Deterministic Mathematical Foundation
Every formula deployed on RFCalTool follows established physical models without empirical guessing, hidden approximations, or proprietary black boxes.
Antenna Terminology & Gain
Defines isotropic reference gain (dBi), dipole gain (dBd), radiation resistance, and directivity ratios.
End-Effect & Velocity Factors
Standard 0.95 end shortening for thin wire dipoles and verified physical transmission line dielectric matrices.
Free-Space Attenuation
Standard spherical wavefront expansion calculations matching international telecommunication models.
RF Exposure & MPE Limits
Controlled occupational and uncontrolled public power density thresholds evaluated across operational frequencies.
Every calculation script is peer-reviewed against canonical textbooks and open-source benchmark suites. Developed in partnership with framecipher.info.