Density Calculator
Calculate density, mass, or volume. Enter any two of the three variables — get the third with material reference data for engineering, chemistry, and shipping.
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m³
Enter your values above to see the results.
Tips & Notes
- ✓Density depends on temperature. Water density: 0°C = 0.9998 g/cm³; 4°C = 1.0000 g/cm³ (maximum); 20°C = 0.9982 g/cm³; 100°C = 0.9584 g/cm³. Gasoline density varies from 0.71 to 0.77 g/cm³ with temperature and blend — always use the actual density at measurement temperature.
- ✓Identifying unknown materials by density: gold 19.3 g/cm³; lead 11.34; copper 8.96; steel 7.85; aluminum 2.70; glass 2.5; concrete 2.3; water 1.0; wood 0.5-0.9; foam < 0.1. If an object has density between 0.5 and 0.9 g/cm³, it is likely wood. Density alone cannot identify a material but can rule out many possibilities.
- ✓Volume by displacement: for irregular objects, submerge in water and measure volume displaced. A rock placed in a 500 ml graduated cylinder causes the water level to rise from 350 ml to 475 ml → volume = 475 - 350 = 125 ml = 125 cm³. If mass = 312.5 g → density = 312.5/125 = 2.5 g/cm³ (matches glass or granite).
- ✓Soil density matters for construction: dry bulk density of loose soil = 1,200-1,800 kg/m³; compacted soil = 1,600-2,000 kg/m³. For a 100 m² excavation 0.5 m deep = 50 m³ of soil: at 1,500 kg/m³ = 75,000 kg = 75 metric tons to remove. Proctor density test determines maximum compaction for foundation preparation.
- ✓Archimedes principle: buoyant force = ρ_fluid × g × V_submerged. An object floats when ρ_object < ρ_fluid. Seawater density = 1,025 kg/m³ (3.5% salt raises density). Ice density = 917 kg/m³ → ice floats with 917/1,025 = 89.5% submerged and 10.5% above water. This is why icebergs are almost entirely underwater.
Common Mistakes
- ✗Not specifying temperature with density — density is temperature-dependent. "Water density = 1.0 g/cm³" is only exactly true at 4°C. Saying "steel density = 7.85 g/cm³" implies room temperature (20°C). For precision chemistry or fluid mechanics, always note measurement temperature.
- ✗Confusing density with concentration — density (g/cm³ or kg/m³) is mass per unit volume for a pure material or homogeneous mixture. Concentration (g/L, mol/L) is the amount of solute per unit volume of solution. A 10% by mass NaCl solution has density ≈ 1.073 g/mL and concentration ≈ 107.3 g/L.
- ✗Using apparent density (with porosity) for solid material calculations — apparent (bulk) density of sand = 1,600 kg/m³; true grain density = 2,650 kg/m³. The difference is pore space. Use apparent density for calculating mass of bulk materials in containers; use true density for particle-level calculations.
- ✗Assuming density is always in SI units — density appears in many unit combinations: g/cm³ (chemistry), kg/m³ (engineering), lb/ft³ (US construction), lb/gal (liquid). 1 g/cm³ = 1,000 kg/m³ = 62.43 lb/ft³ = 8.345 lb/gal. Always verify which unit system is in use.
- ✗Dividing instead of multiplying (or vice versa) — mass = density × volume (multiply); density = mass / volume (divide); volume = mass / density (divide). A common error is computing density = volume / mass instead of mass / volume, giving a result 1/ρ² off for subsequent calculations.
Density Calculator Overview
Density (ρ = m/V) is the fundamental material property that links mass, volume, and composition. Whether identifying unknown materials, calculating structural loads, determining shipping costs, or understanding fluid behavior, density provides the bridge between what a material looks like (its volume) and how it behaves physically (its mass).
Density formula — solve for any variable:
ρ = m/V | m = ρ × V | V = m/ρ | Units: g/cm³ or kg/m³ (1 g/cm³ = 1,000 kg/m³)
EX: Unknown metal object: mass = 892 g, volume = 100 cm³ → ρ = 892/100 = 8.92 g/cm³ — matches copper (8.96) closely, likely copper alloy. Steel pipe 0.05 m³: M = 7,850 × 0.05 = 392.5 kg = 865.5 lbsBuoyancy and flotation:
Floats if ρ_object < ρ_fluid | Buoyant force = ρ_fluid × g × V_submerged | % submerged = ρ_object/ρ_fluid × 100
EX: Iceberg: ρ_ice = 0.917 g/cm³, ρ_seawater = 1.025 g/cm³. Fraction submerged = 0.917/1.025 = 89.5%. A 1,000 t iceberg has 895 t below water, only 105 t (10.5%) visible above surface.Density of common materials:
| Material | g/cm³ | kg/m³ | Comparison to water |
|---|---|---|---|
| Air (20°C, 1 atm) | 0.00120 | 1.204 | 830× less dense |
| Pine wood | 0.55 | 550 | Floats (55% submerged) |
| Ice | 0.917 | 917 | Floats (89.5% submerged) |
| Water (4°C) | 1.000 | 1,000 | Reference |
| Aluminum | 2.70 | 2,700 | 2.7× denser than water |
| Steel | 7.85 | 7,850 | 7.85× denser than water |
| Lead | 11.34 | 11,340 | 11.34× denser than water |
| Gold | 19.30 | 19,300 | 19.3× denser than water |
| Unit | Equivalent | Common Use |
|---|---|---|
| 1 g/cm³ | 1,000 kg/m³ = 1 kg/L | Chemistry, materials science |
| 1 kg/m³ | 0.001 g/cm³ = 0.0624 lb/ft³ | Engineering (SI) |
| 1 lb/ft³ | 16.018 kg/m³ = 0.01602 g/cm³ | US construction, HVAC |
| 1 lb/gal (US) | 119.83 kg/m³ = 0.1198 g/cm³ | Liquid fuels and chemicals |
Frequently Asked Questions
Density (ρ) = mass / volume. Use consistent units. Examples: a steel ball with mass 785 g and volume 100 cm³ → ρ = 785/100 = 7.85 g/cm³ (confirms steel). A liquid: 500 g of cooking oil in a 546 ml container → ρ = 500/546 = 0.916 g/cm³ (typical olive oil density). Water: 1,000 g in 1,000 cm³ (1 liter) → ρ = 1.000 g/cm³. To find volume: V = mass/density. To find mass: M = density × volume.
Densities (g/cm³): gases — air 0.00120, helium 0.000164, CO₂ 0.00184. Liquids — ethanol 0.789, water 1.000, seawater 1.025, honey 1.36-1.45, mercury 13.53. Solids — ice 0.917, wood (pine) 0.5, wood (oak) 0.75, concrete 2.3, glass 2.5, aluminum 2.70, titanium 4.51, steel 7.85, copper 8.96, lead 11.34, gold 19.30, osmium 22.59 (densest natural element). Reminder: materials with density less than 1.0 g/cm³ float in water; greater than 1.0 g/cm³ sink.
Method 1 — Water displacement: weigh the dry object (mass M). Fill a graduated cylinder with water to a known level (V₁). Submerge the object fully; record the new water level (V₂). Volume = V₂ − V₁. Density = M/(V₂−V₁). Method 2 — Archimedes (weight in air vs. water): weight in air = W_air (newtons). Weight submerged = W_submerged. Buoyant force = W_air − W_submerged. Volume = (W_air − W_submerged)/(ρ_water × g). Density = W_air / ((W_air − W_submerged)/ρ_water). Precise to ±0.1% for most solids.
Freight density determines shipping classification and pricing. Freight density = weight (lbs) / volume (cubic feet). NMFC (National Motor Freight Classification): Class 50 (density > 50 lbs/ft³) = cheapest rate; Class 500 (density < 1 lb/ft³) = most expensive. Dimensional weight (DIM weight) for express couriers: DIM weight = (L × W × H in cm) / 5,000 (in kg). If DIM weight > actual weight, DIM weight is billed. A 5 kg package in a 40 × 30 × 20 cm box: DIM weight = 40 × 30 × 20 / 5,000 = 4.8 kg — billed at 5 kg (actual). A 1 kg product in the same box: DIM weight = 4.8 kg — billed at 4.8 kg, not 1 kg.
Fluid density determines hydrostatic pressure: P = ρ × g × h, where h is depth. At 10 m depth in freshwater: P = 1,000 × 9.81 × 10 = 98,100 Pa ≈ 1 atm additional pressure. At 10 m in seawater (ρ = 1,025 kg/m³): P = 1,025 × 9.81 × 10 = 100,553 Pa (2.5% higher). Pipe flow: Reynolds number Re = ρVD/μ depends on density. Heat exchangers: heat transfer calculations require fluid density for mass flow rate (mass flow = density × volumetric flow). Pump selection: higher-density fluids require more power for the same flow rate.
Water has a unique density-temperature relationship: it is densest at 4°C (1.0000 g/cm³), less dense above and below this temperature. Ice at 0°C = 0.917 g/cm³ (less dense than liquid water — why ice floats). Water at 100°C = 0.9584 g/cm³. This property causes lake stratification: cold dense water sinks, warm water rises. For other liquids: ethanol density decreases approximately 0.001 g/cm³ per 2°C increase. Mercury changes about 0.00018 g/cm³ per °C. Gasoline: approximately 0.001 g/cm³ per 2°C — a factor in fuel mass calculations for aviation (aircraft fuel capacity is in mass, not volume).