Engineering Toolbox
Free calculators and reference tables for steel fabricators, mechanical engineers, and designers.
Pressure & Stress
Pa · kPa · MPa · bar · psi
Length
mm · in · ft · thou · μm
Force & Mass
N · kN · lbf · kgf
Temperature
°C · °F · K · °R
Universal Constants
NIST 2018 CODATA
| Constant | Symbol | Value | Unit |
|---|---|---|---|
| Gas constant | R | 8.31446 | J·mol¹·K¹ |
| Boltzmann constant | k_B | 1.38065 × 10²³ | J/K |
| Standard gravity | g | 9.80665 | m/s² |
| Speed of light | c | 299,792,458 | m/s |
| Stefan-Boltzmann | σ | 5.67037 × 10⁻&sup8; | W·m⁻²·K⁻&sup4; |
| Avogadro number | N_A | 6.02214 × 10²³ | mol⁻¹ |
| Atmospheric pressure | P₀ | 101,325 | Pa |
| Planck constant | h | 6.62607 × 10⁻³&sup4; | J·s |
Young's Modulus & Elastic Properties
E · G · ν · σ_y
| Material | E (GPa) | G (GPa) | ν | σ_y (MPa) |
|---|---|---|---|---|
| Structural steel S275 | 205 | 80 | 0.30 | 275 |
| Structural steel S355 | 210 | 81 | 0.30 | 355 |
| Stainless 304 | 193 | 74 | 0.29 | 215 |
| Stainless 316 | 200 | 77 | 0.30 | 205 |
| Cast iron (grey) | 110 | 41 | 0.26 | 130 |
| Aluminium 6061-T6 | 68.9 | 26 | 0.33 | 276 |
| Aluminium 7075-T6 | 71.7 | 27 | 0.33 | 503 |
| Titanium Ti-6Al-4V | 114 | 44 | 0.34 | 880 |
| Inconel 625 | 208 | 79 | 0.31 | 490 |
| HDPE | 0.8 | 0.3 | 0.45 | 23 |
Thermal Expansion
ΔL = α · L₀ · ΔT
ΔL = α × L₀ × ΔT
—
Density & Specific Gravity
| Material | ρ (kg/m³) | SG |
|---|---|---|
| Mild steel | 7850 | 7.85 |
| Stainless 316 | 8030 | 8.03 |
| Aluminium 6061 | 2700 | 2.70 |
| Copper | 8960 | 8.96 |
| Titanium | 4510 | 4.51 |
| Cast iron | 7150 | 7.15 |
| Concrete | 2400 | 2.40 |
| HDPE | 960 | 0.96 |
Hardness Conversion
HRC · HB · HV · tensile
ASTM E140 approximate conversion — enter any value
Beam Deflection
—
Elastic theory · verify critical designs with FEA and codes
Area Moment of Inertia
Ixx · Zxx · r
Bolt Torque
T = K · F · d
T = K · F · d
—
K: dry 0.20–0.22 · oily 0.15–0.18 · greased 0.12–0.15
Section Weight
SHS · RHS · CHS · flat bar
—
Plate & Bar Weight
plate · round bar · hex bar
—
Ohm's Law
V = IR · P = IV
Enter any two — remaining solved automatically
Voltage Divider
Vout = Vin · R2 / (R1+R2)
Vout = Vin × R2 / (R1 + R2)
—
Find R2 for target Vout
—
E-Series Nearest Value
E12 · E24 · E48 · E96
ISO Fits
H7/g6 · tolerance limits
—
| Type | Example | Use |
|---|---|---|
| Close running | H7/g6 | Precision sliding |
| Easy running | H7/f7 | Bearings, bushings |
| Push (trans.) | H7/k6 | Located, removable |
| Press fit | H7/p6 | Driven, semi-permanent |
| Force fit | H7/s6 | Tight press, no movement |
GD&T Symbol Reference
ISO 1101 / ASME Y14.5
Tap Drill Size Chart
metric coarse · tap drill · clearance drill
| Thread | Pitch (mm) | Tap drill (mm) | Close fit (mm) | Free fit (mm) |
|---|---|---|---|---|
| M2 | 0.40 | 1.60 | 2.20 | 2.40 |
| M2.5 | 0.45 | 2.05 | 2.70 | 2.90 |
| M3 | 0.50 | 2.50 | 3.20 | 3.40 |
| M4 | 0.70 | 3.30 | 4.30 | 4.50 |
| M5 | 0.80 | 4.20 | 5.30 | 5.50 |
| M6 | 1.00 | 5.00 | 6.40 | 6.60 |
| M8 | 1.25 | 6.80 | 8.40 | 9.00 |
| M10 | 1.50 | 8.50 | 10.50 | 11.00 |
| M12 | 1.75 | 10.20 | 13.00 | 13.50 |
| M14 | 2.00 | 12.00 | 15.00 | 15.50 |
| M16 | 2.00 | 14.00 | 17.00 | 17.50 |
| M18 | 2.50 | 15.50 | 19.00 | 20.00 |
| M20 | 2.50 | 17.50 | 21.00 | 22.00 |
| M22 | 2.50 | 19.50 | 23.00 | 24.00 |
| M24 | 3.00 | 21.00 | 25.00 | 26.00 |
| M27 | 3.00 | 24.00 | 28.00 | 30.00 |
| M30 | 3.50 | 26.50 | 31.00 | 33.00 |