Free Converters & Engineering Calculators
31 instant tools for engineers, machinists and buyers — units, metal weights, threads, valve flow and pump hydraulics. All calculations run in your browser: fast, private, free.
Unit Converters
📏
Length
mm · cm · m · km · in · ft · yd · mi
⚖️
Weight & Mass
g · kg · ton · oz · lb · stone
🟩
Area
m² · ha · ft² · acre
🧊
Volume
L · m³ · gal · barrel · ft³
🌡️
Temperature
°C · °F · K · °R
🏃
Speed
km/h · mph · m/s · knot · SFM
🧯
Pressure
MPa · bar · psi · kgf/cm² · atm
🔩
Torque
N·m · kgf·m · lbf·ft
💪
Force
N · kN · kgf · lbf · tf
⚡
Energy
J · kJ · cal · kWh · BTU
🔋
Power
W · kW · hp · PS · BTU/h
💧
Flow Rate
m³/h · L/min · GPM · bbl/d
⏱️
Time
ms · s · min · h · day · year
📐
Angle
° · rad · gon · arcmin
💾
Data Storage
bit · B · KB · MB · GB · TB
Metal & Weight
🔩
Metal Weight Calculator
6 shapes × 12 materials
⬜
Steel Plate Weight
per plate & per m²
🛢️
Pipe Weight
OD × wall × length
⭕
Round Bar Weight
D²/162 steel formula
🔼
Square Tube Weight
SHS hollow sections
⬡
Hex Bar Weight
across-flats hex stock
📊
Metal Density Chart
25+ alloys, g/cm³ · lb/in³
Threads & Fasteners
🪛
Tap Drill Calculator
metric + UNC/UNF chart
🌀
Metric Thread Chart
M1.6–M64 full dimensions
🧵
UNC / UNF Chart
unified inch threads
🔧
Bolt Torque Calculator
8.8 / 10.9 / 12.9 / A2-70
📐
Three-Wire Measurement
M value & best wire size
Fluid & Pump
Geometry
📐
Triangle Calculator
area · angles (SSS)
⭕
Circle Calculator
area · circumference
🛢️
Cylinder Calculator
volume · surface
⚪
Sphere Calculator
volume · surface
🍦
Cone Calculator
volume · slant height
📦
All 16 Shapes →
2D & 3D geometry
Machining
Daily Life
🥤
Cups to mL
cooking volume
⚖️
Oz to Grams
kitchen weight
👟
Shoe Size Converter
US · UK · EU · cm
⛽
MPG ↔ L/100km
fuel economy
📅
Date Duration
days between dates
💪
BMI Calculator
body mass index
🎂
Age Calculator
exact age
📏
CM to Feet
height converter
Physics
🧊
Density
ρ = m / V
🏎️
Kinetic Energy
KE = ½mv²
🪂
Free Fall
time & impact speed
🔌
Ohm's Law
V · I · R · P
🎯
Projectile Motion
range · apex · time
🎈
Ideal Gas Law
PV = nRT
💡
Energy Cost
watts → kWh → $
🎱
Momentum
p = mv
Tolerances & Machining
💎
Hardness Converter
HRC · HBW · HV · HK · HS
📐
ISO IT Tolerance
standard grade bands
🔩
H7 Shaft Fit
clearance · interference
🪚
Chip Load
feed per tooth
⚒️
Cutting Force
Fc = kc·ap·f
⚡
Machining Power
kW at the spindle
🧴
Grit to Micron
abrasive chart
Most Popular Conversions
| Conversion | Formula | Example |
|---|---|---|
| 1 meter to mm | 1 m = 1000 mm | 2.5 m = 2500 mm |
| 1 inch to mm | 1 in = 25.4 mm | 2 in = 50.8 mm |
| 1 kg to lb | 1 kg = 2.20462 lb | 10 kg = 22.046 lb |
| 1 MPa to psi | 1 MPa = 145.038 psi | 5 MPa = 725.19 psi |
| 1 bar to MPa | 1 bar = 0.1 MPa | 16 bar = 1.6 MPa |
| 1 N·m to lbf·ft | 1 N·m = 0.73756 lbf·ft | 50 N·m = 36.88 lbf·ft |
| Kv to Cv | Cv = 1.156 × Kv | Kv 25 = Cv 28.9 |