Queendom Tools

Enter price, monthly rent, and annual expenses to get net operating income and cap rate instantly. Formula shown. Free, no signup, no email.

Accurately project investment growth using a compound interest calculator with monthly contributions.

Convert your dog's age to human years with the AVMA medium-dog curve (15, then 9, then 5 a year) plus the 16·ln(age)+31 epigenetic estimate.

Enter your teams and get a single round-robin schedule grouped by round — every team plays every other once, with automatic byes for odd counts.

Enter water and sugar to get finished syrup volume, °Brix and density. Sucrose adds 0.63 L per kg — 1 kg in 1 L water makes 1.63 L.

Enter your TV's diagonal and aspect ratio to get ideal seating distance for SMPTE 30° and THX 40° angles, in metres and feet.

Clean pasted text in your browser: strip HTML tags, replace typographic characters, trim lines, collapse spaces and remove blank or duplicate lines.

Create perfect CSS box-shadow values with live sliders, preview, and the full 6-value syntax for UI/UX designers.

Convert #RRGGBB hex codes to RGB, HSL, and instantly check WCAG 2.1 contrast ratios. Perfect for UI/UX designers and web developers.

Convert any text to the official NATO phonetic alphabet instantly. Encode callsigns & scripts accurately for aviation & support teams.

Convert pixels to rems instantly while adjusting root font size. Bidirectional tool for frontend developers.

Clean up your text lists quickly: dedupe case-insensitively, keep first occurrence, sort A-Z, Z-A or by length – ideal for marketers & analysts.

Enter mean, sigma, USL and LSL to get Cpk instantly, with Cpu and Cpl shown side by side so you can see which specification limit is limiting.

Compute GUM Annex H.5 one-way ANOVA variance components, F ratio and standard uncertainties of the mean from group means and standard deviations.

Apply a Kish grid in the field: pick the assigned table A–F, enter eligible members, and get the selected respondent number with the table row shown.

Enter sample size, proportion and confidence level to get the survey margin of error in percentage points and the confidence interval range, instantly.

Build a GUM uncertainty budget with standard and combined uncertainty, effective degrees of freedom, Student t coverage factors, and expanded uncertainty.

Normal tolerance interval k factors and limits from N, mean and s: two-sided Howe, one-sided Natrella and exact non-central t.

Enter each group's mean, SD and n to get the t-statistic, degrees of freedom and Welch or pooled method — no raw data needed.

Fit a two-parameter Weibull distribution to failures and suspensions using maximum likelihood. Calculate life, B-life, and reliability.

Compute X-bar and R chart control limits from the grand mean and average range. A2, D3, D4 and d2 for subgroup sizes 2–10, with estimated sigma.

Convert bioreactor gas flow and working volume to vvm and back, with superficial gas velocity from the vessel diameter and worked examples.

Exponential feed rate F(t) for a fed-batch culture held at constant specific growth rate, in L/h and mL/h, with biomass in the vessel.

Enter any three of initial amount, remaining amount, half-life, or elapsed time and get the fourth instantly, plus decay constant λ and percent remaining.

Quick conversion of pH, pOH, hydrogen ion, and hydroxide ion concentrations at 25 °C for chemistry students.

Calculate Rushton turbine impeller Reynolds number, power draw from the power number, or Po from measured shaft power, plus tip speed and P/V.

Enter reactant masses, molar masses and balanced coefficients to get the limiting reagent, theoretical yield in grams and leftover excess.

Estimate the volumetric oxygen transfer coefficient kLa of an aerated stirred tank with the Van't Riet correlation, plus the oxygen transfer rate.

Enter room volume, RT60 and source placement to get critical distance Dc in metres using Dc = 0.057 × √(Q × V / RT60). Free, no signup.

Calculates combined SPL from multiple noise sources. Instant SPL sum for acoustic technicians, summing up to 10 uncorrelated sound pressure levels.

Calculate the day-night average sound level Ldn from daytime Leq (07:00-22:00) and nighttime Leq (22:00-07:00) with the 10 dB night penalty.

Convert unweighted octave band levels from 31.5 Hz to 8 kHz into A-weighted band levels and the overall A-weighted level in dBA.

Convert a sound pressure level Lp measured at distance r to sound power level Lw with the free-field relation, including directivity factor Q.

Maximum A-weighted level Lmax of a single train passby at a receiver from locomotive and rail car SELref, train speed and closest distance.

Convert a close-by transit passby or stationary source measurement to the source reference SEL at 50 ft and 50 mph, with every term shown.

Compute Leq(1hr), Ld, Ln and Ldn at 50 ft for a stationary transit source from its reference SEL, event duration and event counts, with every step.

Calculate minimum exhaust CFM for a Type I commercial canopy hood from hood length, mounting type and appliance duty using IMC rates. Estimate only.

Enter up to five layers' thickness and conductivity to get each R value, total R, heat flux in Btu/hr-ft², and the temperature drop across every layer.

Calculate cooling tower evaporation, blowdown and makeup water in GPM from recirculation rate, range ΔT and cycles of concentration.

Instantly estimate the chilled water flow (GPM) needed for a CRAH unit based on cooling load (BTU/hr) and ΔT. Perfect for HVAC engineers.

Enter duct dimension and points per side (5, 6 or 7) to get ASHRAE 111 Log-Tchebycheff pitot insertion depths in inches for a rectangular duct traverse.

Calculate SMACNA allowable duct leakage in CFM from duct area, test pressure, seal class and shape using F = CL × P^0.65. CL 6/12/24 rect, 3/6/12 round.

Work out EIRP and ERP in dBm and watts from transmitter power, cable and connector loss and antenna gain. Handles dBm/W and dBi/dBd in one live view.

Free space path loss in dB from 20·log10(d) + 20·log10(f) + 32.44 — distance in km, frequency in MHz — then subtract TX and RX antenna gain.

Work out first Fresnel zone radius and the 60% clearance height for a wireless link from path length in km, frequency in GHz and obstacle position.

Compute parabolic dish gain in dBi from diameter, frequency and aperture efficiency. Shows wavelength and the G = 10·log10(η(πD/λ)²) equation.

Radar and visual horizon distance from antenna height plus optional target height, in feet or metres. Uses 1.22√h radar, 1.17√h visual; range in nm and km.

Calculate thermal noise floor (kTB) and receiver sensitivity from bandwidth, noise figure, temperature and required SNR. Anchored at −174 dBm/Hz at 290 K.

Size a horizontal flare knock-out drum using droplet settling, liquid holdup and residence time. Includes SI/US units and automatic sizing.

Estimate battery cell and pack heat generation with the Bernardi equation: Joule heat plus reversible entropic heat, for cooling system design.

Estimate heat recovered, fuel saved and annual cost avoided by returning hot condensate, using Q = m × 4.186 × (Tc − Tm) ÷ 3600 and boiler efficiency.

Size a fuel cell power plant from DC output, cell voltage and current density: total current, active cell area, number of cells and stacks.

Calculate low-pressure natural gas pipe flow capacity (CFH) using the official IFGC/NFPA 54 formula.

Instantly convert inverter apparent power (kVA) and power factor to real power (kW) and reactive power (kVAR) for battery storage system sizing.

Enter height difference, winter-solstice solar altitude and azimuth to get minimum inter-row spacing from D = H × cos(az) ÷ tan(alt).

Convert weight loss, area, time and density into corrosion rate in mm/y and mpy with the ASTM G31 formula CR = (K × W) / (A × T × D).

Bragg's law calculator: turn an XRD 2θ or θ peak position into d-spacing in Å and nm for order n, with Cu Kα1, Mo Kα or a custom wavelength.

Enter C, Mn, Cr, Mo, V, Ni, Cu, Si and B in wt % to get IIW CEV and Ito-Bessyo Pcm carbon equivalent side by side, with both formulas shown.

Compute the resistance to earth of one vertical cylindrical anode in uniform soil with the Dwight's equation. Soil resistivity table and worked case.

Blend three scrap or return charges and get the mass-weighted alloy wt% from Sum(Wi·Ci)/Sum(Wi), with total charge mass — for preliminary melt estimation.

Lime saturation factor calculator for cement clinker or raw meal: LSF from CaO, SiO2, Al2O3, Fe2O3, MgO correction, silica and alumina moduli.

Convert feed, concentrate and tailings assay grades into flotation recovery % using the two-product formula R = 100·c·(f − t) / (f·(c − t)).

Calculate weld heat input in kJ/mm from voltage, current and travel speed, with EN ISO 1011-1 arc efficiencies for SAW, SMAW, GMAW and GTAW.

Quickly compute soil resistivity in Ohm-cm using the Wenner 4-pin formula per ASTM G57 for CP groundbeds. Instant results for field surveyors.

Compute wet film thickness from dry film targets and volume solids. Instant tool for industrial painters to ensure coating specs meet cure requirements.

Enter wear coefficient K, load W in N, sliding distance L in mm and hardness H in MPa to get sliding wear volume V = K·W·L/H in mm³, live.

Fit the ASTM D341 Walther equation to two viscosity–temperature points and get kinematic viscosity in cSt at any target temperature, with the A and B…

Convert balance inertia (mg·cm²) and beat rate (18000, 21600 or 28800 vph) into balance spring stiffness in µN·m/rad using k = I(2πf)².

Enter wire diameter, mean coil diameter, active coils and shear modulus to get helical compression spring rate k in N/mm, with the formula shown.

Calculate force proving instrument calibration uncertainty per EURAMET cg-4: quadratic fit, wc, expanded U and W at each force step.

Convert driver and driven tooth counts plus input RPM and torque into gear ratio, output speed and output torque — inverse speed, direct torque.

Calculate minimum and central EHL film thickness for point and elliptical contacts using Hamrock–Dowson formulas, with units and validity warnings.

Compute Hertzian contact radius, maximum and mean pressure and elastic approach for a sphere on a flat, on a second sphere or in a concave socket.

Enter flow in L/min, pressure in bar and pump efficiencies to get required shaft power in kW from P = (Q * p) / (600 * η).

Compute permissible residual unbalance from balance grade G, rotor mass and max service speed — per plane, residual mass at radius, and centrifugal force.

Convert raw >4, >6 and >14 µm(c) particle counts per mL or per 100 mL into an ISO 4406 code X/Y/Z, using the scale limits from 0.01 to 2,500,000 per mL.

Per-point pressure gauge calibration error, hysteresis, standard and expanded uncertainty and error span in bar or MPa, per EURAMET cg-17.

Least-squares transmission factor through zero, point sensitivity, hysteresis and expanded uncertainty for a pressure transducer in bar and mV/V.

Estimate viscosity at EHL contact pressure with the Roelands equation and see the Barus exponential beside it.

Compute the Sommerfeld number S = (r/c)²μN/P and the Hersey number μN/P for a hydrodynamic journal bearing from radius, clearance, viscosity, rpm and load.

Calculate torque transducer calibration uncertainty per EURAMET cg-14: mean indication, repeatability, reproducibility, cubic fit and uncertainty.

Enter wheel teeth and pinion leaves to get beats per hour, frequency in Hz and fourth-wheel turns per hour — 18,000 vph example worked through.

Compute balance calibration error and expanded uncertainty per EURAMET cg-18 H1 option 2, using a Student t coverage factor.

Estimate injection molding clamping tonnage from projected area and cavity pressure. See the formula and the intermediate force in kN as you type.

Fluting medium length and weight for a length of corrugated board from the take-up factor: C-flute 1.44 (US EPA example) or your own mill factor.

Compute single-screw drag flow Q = 0.5·π²·D²·N·h·sin φ·cos φ from screw diameter, channel depth, rpm and helix angle — in cm³/s and kg/h.

Instantly compute how many meters of PLA, ABS, or PETG filament remain on a spool. Ideal for 3D printing hobbyists.

Estimate molded-part cooling time in seconds from wall thickness, thermal diffusivity, and melt, mold and eject temperatures. Formula shown.

Convert part and runner volume to shot weight in grams at solid density, plus the melt volume to dose at melt density with cushion. Preliminary estimate.

Estimate warp yarn weight in pounds from total ends, warp length in yards and Ne count using Weight = (Ends × Length) ÷ (840 × Ne).

Convert English cotton count Ne, metric count Nm, tex, decitex and denier in one pass. tex = 590.5 ÷ Ne, tex = 1000 ÷ Nm, denier = 9 × tex.

Estimate single-pulse laser ablation depth from penetration depth δ = 1/α and fluence with the Beer-Lambert model: Depth = δ × ln(F/F_th).

Calculate thin-orifice molecular conductance in L/s from area, molar mass and temperature with C = A√(RT/2πM). Flags wall thickness over 0.1× diameter.

Compute Rayleigh length, depth of focus, beam radius at distance z and half-angle divergence from waist radius, wavelength and M² for Gaussian laser beams.

Hertz–Knudsen calculator: enter pressure, temperature, molar mass and sticking coefficient to get impingement flux and monolayer formation time for a…

Estimate viscous-flow tube conductance in L/s from diameter, length, average pressure and gas viscosity — with a Kn < 0.01 validity check.

Convert latitude and longitude to Hotine Oblique Mercator x, y and point scale factor k for a line through two points (Snyder alternative A).

Lambert azimuthal equal-area projection, oblique ellipsoidal aspect: convert latitude and longitude to x and y (Snyder eqs. 24-17 to 24-20).

Lambert conformal conic forward calculator: latitude and longitude to x, y and scale factor k, two standard parallels, ellipsoid or sphere.

Convert latitude and longitude to x, y and point scale factor k with the oblique stereographic projection on the ellipsoid (Snyder, USGS PP 1395).

Convert latitude and longitude to x, y and scale factor k on the north polar azimuthal equidistant projection (ellipsoid), after Snyder 1987.

Compute composite gutter flow from spread or spread from flow for a curbed street gutter with a depressed section, using the Izzard form of Manning.

Compute curb-opening inlet length for total interception, efficiency, and bypass flow on grade with HEC-22 Eq. 7.10 and 7.13. Enter Q, SL, Sx, n and L.

Instantly calculate how many 4x8 drywall sheets you need for your project. Includes automatic 10% waste margin for cuts and errors. Free contractor tool.

Calculate roof drain flow in GPM from roof area and rainfall rate using the IPC 1106 rule: 1 in/hr on 96 sq ft ≈ 1 GPM, with drain sizing notes.

Convert Superpave gyratory trial-blend data into estimated binder content, VMA, VFA and density at 4.0% air voids using the FHWA workbook method.

Compute mean, standard deviation, coefficient of variation and skew of an annual peak flow series, with a table of normalized deviations.

Estimate the daily total ammonia nitrogen (TAN) your fish produce from feed, the load your biofilter must nitrify, using P_TAN = F × PC × 0.092.

Darcy-Weisbach head loss and pressure drop from pipe diameter, length, roughness, density and viscosity — friction factor from 64/Re or Swamee-Jain.

Compute Kr, Ke, Kc = Kcb + Ke, ETc and top-soil depletion De with the FAO-56 dual crop coefficient method, for one day or a run of drying days.

Convert EC (µS/cm or mS/cm) to TDS ppm on the 0.5 NaCl, 0.64 Eutech and 0.7 442 scales at once — see all three readings and the formula.

Estimate shear stress, critical size Dc and the degradation depth Ys at which an armor layer could form on a coarse, well graded bed (HEC-20).

Water, brake and input horsepower, input kW, kWh per 1,000 gallons and overall pumping plant efficiency from flow, head and three efficiencies.

Compute pressure wave speed (Korteweg), Joukowsky surge ΔP = ρ·a·ΔV in Pa, bar and psi, and the critical closure time 2L/a for your pipe.

Compute LSI and Ryznar RSI from pH, TDS, temperature, calcium hardness and alkalinity in mg/L as CaCO3 — with the full pHs formula shown.

Calculate daily FAO-56 reference evapotranspiration from weather, sunshine or measured radiation, with transparent formulas and optional crop ET.

Estimate annual runoff, evaporation and infiltration for a retention pond and see the net water budget in ft³/yr, per FHWA HEC-22 Example 10.13.

Get allowable depletion, gross application depth, irrigation interval and required sprinkler capacity in gpm from crop water use, root zone and soil data.

Theis drawdown calculator for a confined aquifer: u, W(u), drawdown, Cooper-Jacob check and time to reach a target drawdown.

Calculate TR-55 peak discharge with NRCS rainfall types, curve number, time of concentration, and pond adjustment in US or SI units.