03 // Bidirectional STEM Calculators // PHYSICSΔL = (α × 10⁻⁶) × L₀ × ΔT

Thermal Linear Expansion (ΔL = αL₀ΔT) Calculator

Linear thermal expansion predicts the fractional change in length ΔL of a solid structural member of initial length L₀ subjected to a temperature change ΔT: ΔL = α × L₀ × ΔT.

ΔL = (α × 10⁻⁶) × L₀ × ΔT

Pick which value you want to calculate (or type into any field):Solving for: ΔL — Length Expansion

Length ExpansionCalculated

Change in length in meters (switch unit to mm for precision readout)

1.0000e-610

Expansion Coefficient (μm/m·K)

Coefficient of linear thermal expansion in parts per million per °C/K

0.5200

unit

Original Length

Baseline span length at initial temperature in meters

0.15,000.00

Temperature Change

Temperature rise (T_final - T_initial) in °C or Kelvin

11,000.00

deg

Calculated Result · Length Expansion (ΔL)

0.0144m

Converted units:

Step-by-Step Calculation

01Canonical Law: ΔL = (α × 10⁻⁶) × L₀ × ΔT

02Given Inputs (Base Units): α (10⁻⁶/K) = 12, L₀ = 30 m, ΔT (°C or K) = 40

03Solve for ΔL (Length Expansion): ΔL = 0.0144 m

Linear thermal expansion predicts the fractional change in length ΔL of a solid structural member of initial length L₀ subjected to a temperature change ΔT: ΔL = α × L₀ × ΔT.

Real-World Reference Values

Structural Carbon Steel (A36)α = 11.7 – 12.2 × 10⁻⁶ /K

30m bridge girder expands 14.4 mm over ΔT = 40 °C

Aluminum 6061-T6 Alloyα = 23.1 × 10⁻⁶ /K

Nearly double the expansion rate of steel

Invar 36 / Fused Quartzα = 1.2 / 0.55 × 10⁻⁶ /K

Ultra-low thermal drift metrology materials

20-Row Comparison Table

Length Expansion (ΔL) · Expansion Coefficient (μm/m·K) (α (10⁻⁶/K))

Compare across:

Thermal Linear Expansion (ΔL = αL₀ΔT) Calculator — Expansion Coefficient (μm/m·K) → Length Expansion
#	Expansion Coefficient (μm/m·K) (α (10⁻⁶/K))	Length Expansion (m)	Δ %
01	0.5	0.0006 m	-95.83%
02	2.549	0.003059 m	-78.76%
03	4.598	0.005518 m	-61.68%
04	6.647	0.007976 m	-44.61%
05	8.6961	0.010435 m	-27.53%
06	10.7451	0.012894 m	-10.46%
07	12 Current	0.0144 m	0.00%
08	14.8431	0.017812 m	+23.69%
09	16.8921	0.020271 m	+40.77%
10	18.9411	0.022729 m	+57.84%
11	20.9901	0.025188 m	+74.92%
12	23.0391	0.027647 m	+91.99%
13	25.0882	0.030106 m	+109.07%
14	27.1372	0.032565 m	+126.14%
15	29.1862	0.035023 m	+143.22%
16	31.2352	0.037482 m	+160.29%
17	33.2842	0.039941 m	+177.37%
18	35.3332	0.0424 m	+194.44%
19	37.3822	0.044859 m	+211.52%
20	39.4313	0.047318 m	+228.59%

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Frequently Asked Questions

How do I read ΔL directly in millimeters?+

Switch the inline unit dropdown on ΔL from Meters (m) to Millimeters (mm). The default 0.0144 m displays immediately as 14.4 mm.

Is ΔT the same in Celsius and Kelvin?+

Yes. Because Celsius and Kelvin have identical degree increments, a temperature change ΔT of 40 °C equals 40 K.

What happens if a heated beam is rigidly clamped at both ends?+

Preventing thermal expansion ΔL induces compressive thermal stress σ = E × α × ΔT, which can buckle rails or fracture concrete.