TestTalkHQ — Free Calculators & Tools
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This is the index for TestTalkHQ calculators and interactive tools. Open a category hub below — welding, electrical, air, shop safety, machining & fabrication — or jump to export tools, the new HVAC ductulator foothold, and guides. No registration, no paywalls.
Calculators return sizing and settings. Interactive tools export PDFs, G-code, CSV, JSON, and symbols. Guides cover how-tos and troubleshooting. Each link below is the canonical place to maintain that list — not a second copy of every item.
Welding Calculators
MIG, TIG, Stick, Flux Core, heat input, gas, duty cycle, and weld cost calculators.
Open Hub →Electrical Calculators
NEC breaker, wire, conduit, voltage drop, EV, panel, motor, and load calculators.
Open Hub →Air Compressor Calculators
CFM sizing, per-tool CFM requirements, tank runtime, compressed-air cost, and related air-system tools.
Open Hub →Fall Clearance Calculator
Required fall-arrest clearance from free fall, deceleration, harness stretch, and safety factor vs available clearance. Starting point — verify OSHA 1926.502 / ANSI Z359.1.
Open Hub →Shop Safety Calculators
Grinder RPM, bolt torque, LOTO checklist, arc flash, fume CFM, noise, respirator, and shop safety tools.
Open Hub →Machining & Fabrication
Lathe, milling, drill, tap, chip load, press brake, CNC plasma pierce/cut speed, sheet metal bend, and tolerance tools.
Open Hub →Carpentry Calculators
Carpentry/framing vertical — stair stringer, deck stair, rafter length / roof pitch, board-foot, joist-span, deck post, and fence-line post spacing calculators, plus layout, troubleshooting, and IRC span tables.
Open Hub →Roofing Calculators
Roofing vertical — shingle squares, drip edge lineal, metal panels, gutters, ice & water, snow load, and pitch tools. Starting point, not a bid or permit.
Open Hub →Roofing Nail & Fastener Calculator
Squares or sq ft, 3-tab vs architectural, 4-nail vs 6-nail high-wind, waste, and nail length by 7/16, 1/2, or 5/8 in decking. Same 100 sq ft square as the shingle takeoff.
Open Hub →Snow Guard Spacing Calculator
The published vector force method: design snow load x sin(roof angle) x eave-to-ridge rafter x seam spacing gives the tributary force on every attachment, then the rows a tested-ultimate capacity covers at the MCA factor of safety of 2.0. Prints the prescriptive vendor spacing table beside it and says which governs.
Open Hub →Plumbing Calculators
Plumbing vertical — fixture units, water heater, expansion tank, drain slope, DWV vent, and water-supply pipe sizing. Starting point, not a plumber’s survey or local code.
Open Hub →Automotive Calculators
First automotive vertical — tire size vs speedometer error from two size codes (diameter %, true vs indicated speed, revs per mile, ±3% fitment flag). Starting point, not a load or rubbing certificate.
Open Hub →Tire Size & Speedometer Error Calculator
Compare original vs proposed tire sizes. Overall diameter %, speedometer error at a true speed, revolutions per mile, and a ±3% fitment flag.
Open Hub →Braking / Stopping Distance Calculator
Reaction plus braking distance from speed, reaction time, and road surface. Physics estimate under assumed conditions — not a guarantee of actual stopping distance.
Open Hub →Trip Fuel Cost Calculator
Gallons, total fuel cost, and cost per mile from trip distance, mpg, and pump price. Round-trip and multi-trip commute modes.
Open Hub →12V DC Wire Gauge Calculator
Minimum copper AWG from amp draw, one-way feet, 12V or 24V, and allowable voltage drop (default 3%). Actual volts, percent, and pass/fail.
Open Hub →Coolant Mix Ratio Calculator
Quarts or liters of antifreeze concentrate and distilled water for a target freeze/boil point (ethylene glycol, 15 psi). Fresh fill or top-off. Never exceed 70% concentrate.
Open Hub →Fixture Unit Calculator
Total WSFU from IPC 2021 Table E103.3(2) and DFU from Table 709.1, then take each number to supply, vent, and slope. Starting point for the plumbing vertical.
Open Hub →Water Heater Sizing Calculator
Recommended tank gallons and first-hour rating from household size, bathrooms, peak-usage scenario, and gas vs electric. DOE Energy Saver worksheet starting point.
Open Hub →Expansion Tank Sizing Calculator
Minimum potable expansion-tank gallons from heater volume, incoming pressure, PRV setting, and temperature rise. Boyle’s-law acceptance at 150 psig T&P. Starting point, not a hydronic boiler tank.
Open Hub →Copper Pipe Expansion Loop Calculator
How far a copper run grows between its anchors, and the developed length of coil or offset that absorbs it. Movement, loop length, coil radius, the Table 14.8 cross-check and support spacing, from the CDA Copper Tube Handbook.
Open Hub →Drain Pipe Slope Calculator
Minimum drop over a horizontal drain run from IPC 2021 Table 704.1 by pipe diameter and length — inches per foot, percent, UPC 708.1 comparison, and a joist-bay headroom flag. Prescriptive starting point, not local code.
Open Hub →DWV Vent Sizing Calculator
Minimum individual/branch vent diameter from IPC 2021 §906.2 by DFU load and developed length, plus UPC Table 703.2 comparison. Prescriptive starting point, not a wet vent or local code.
Open Hub →Water Supply Pipe Sizing Calculator
Minimum trunk/branch diameter from IPC 2021 Table E104.1 by WSFU, developed length, and pressure, plus UPC Table 610.4. Prescriptive starting point, not a hydraulic calc or DFU.
Open Hub →Well Pump Sizing Calculator
TDH from well depth, fixture lift, pipe friction, and cut-out PSI; recommended 1/2–1.5 HP class and pressure-tank gallons. Starting point, not a pump curve. Not a sump pump.
Open Hub →Gas Pipe Sizing Calculator
Natural gas or propane Schedule 40 steel and CSST from IFGC Table 402.4 by BTU load, developed length, and fittings. Starting point — verify local fuel gas code.
Open Hub →Water Softener Sizing Calculator
Salt-based ion-exchange grain class from household size, hardness (GPG or ppm), and optional iron. 7-day cycle with a 25% reserve. Starting point, not a water test, not a salt-free conditioner.
Open Hub →Deck Stair Calculator
Exterior treated 2x12 stringers — step count, rise/run, length, 2 or 3 stringers, and a typical IRC flag (same 7.75 in / 10 in as interior unless local amendments differ).
Open Hub →Rafter Length & Roof Pitch Calculator
Common rafter length, pitch in degrees and X/12, plumb and birdsmouth angles. Span or run, pitch or rise, overhang. Commons only — not hip/valley.
Open Hub →Hip / Valley Rafter Length Calculator
Hip and valley length from common-rafter run and pitch. Diagonal run = run × 1.4142, then length, plumb, and seat. Regular 90° corners — starting point, not gospel.
Open Hub →Board Foot Calculator
Board feet per piece and total BF from nominal thickness, width, length, and quantity. Optional $/board-foot estimated cost.
Open Hub →Deck & Floor Joist Span Calculator
Maximum tabulated joist span from IRC 2021 tables by species, size, spacing, and floor vs deck. Starting point — verify local code and the grade stamp.
Open Hub →Deck Post Spacing Calculator
Maximum tabulated post spacing from IRC 2021 Table R507.5(1) by beam size, species, and joist span — the same cell as beam span, read as on-center post spacing.
Open Hub →Deck Ledger Board Fastener Calculator
On-center spacing for 1/2-inch lag screws or through-bolts from joist span, plus fastener count for the ledger length. Starting point — verify IRC Table R507.9.1.3(1).
Open Hub →Fence Post Spacing & Concrete Calculator
Fence-line post count, actual on-center spacing, and bagged concrete from type, height, run, and hole size. Not IRC deck beam posts.
Open Hub →Fence Post Spacing and Concrete Guide
How spacing changes by fence type, height, and wind, how to size the hole for frost, and how to calculate concrete per hole.
Open Hub →Common Fence Post Problems and Solutions
Leaning and heaving posts, rot at the grade line, frost heave, panel sag from over-wide spacing, and gate posts that walk.
Open Hub →Concrete vs Gravel vs Packed Dirt for Fence Posts
Cost, labor, drainage, climate, and long-term stability for each setting method. None of these always wins.
Open Hub →CNC Plasma Pierce Height & Cut Speed Calculator
Gantry pierce height, pierce delay, cut height, and IPM starting range from material, thickness, and 40–105A — distinct from handheld torch amps.
Open Hub →HVAC Duct Sizing
Equal-friction ductulator — round and rectangular sizing from known CFM, plus guide, troubleshooting, and round vs rectangular.
Open Hub →External Static Pressure Calculator
HVAC TESP from supply + return static vs the blower nameplate — high/low ESP, airflow notes, and companion measurement / CFM articles.
Open Hub →Duct CFM Calculator
CFM from anemometer velocity (FPM) × round or rectangular inside area — traverse average, not a center-point reading.
Open Hub →Superheat / Subcooling Calculator
Piston superheat or TXV subcooling from line temperature, gauge pressure, and R-410A / R-22 / R-32 — target range with overcharge, undercharge, and airflow flags.
Open Hub →Delta-T (Temperature Split) Calculator
HVAC return vs supply air split with a humidity-adjusted expected band (typical AC 16–22°F) — high split flags airflow, low split flags charge/coil.
Open Hub →Furnace Sizing Calculator
Heating BTU output from sq ft, climate zone, insulation, and ceiling height, then furnace input by AFUE and a round-up to 40k–120k. Starting point — not Manual J heat loss.
Open Hub →Ductless Mini-Split Sizing Calculator
Per-zone cooling BTU from climate, insulation, ceiling height, sun, and occupants — round up to common head sizes and total multi-zone system load. Starting point — not Manual J / Manual S.
Open Hub →HVAC Job Cost & Pricing Calculator
Quote an HVAC service call, repair, or change-out: loaded labor, equipment, refrigerant, ductwork, disposal, permit, overhead, and markup or margin.
Open Hub →Structural Fab Tools (New)
First structural-fab vertical on TestTalkHQ — steel beam span/size & deflection calculator, guide, troubleshooting, and check vs auto-select. Preliminary only; PE required for construction.
Open Hub →Office & Insurance Tools
Percentage math, coinsurance penalty, replacement cost, ACV vs RCV, umbrella threshold, and bundling discount estimators for agents and office use.
Open Hub →Interactive Tools
Export-oriented builders: PDF templates, G-code, CSV, JSON WPS drafts, weld symbols — plus the HVAC ductulator and the new structural steel beam calculator.
Open Hub →Guides & Troubleshooting
How-tos, charts, and troubleshooting articles — separate from calculators and tools.
Open Hub →