Curies Law Calculator - Susceptibility by Temperature

Use this curies law calculator to compute susceptibility and magnetization from Curie constant, kelvin temperature, and applied field.

Updated: June 24, 2026 • Free Tool

Curies Law Calculator

Use kelvins for the dimensionless susceptibility form.

Enter thermodynamic temperature in K, not degrees Celsius.

Use A/m for the SI M = χH form.

Controls rounding for the main outputs.

Results

Magnetization
0A/m
Susceptibility χ 0
Inverse susceptibility 0
Temperature check 0°C

What Is Curies Law Calculator?

A curies law calculator estimates how strongly a paramagnetic material responds to an applied magnetic field at a chosen absolute temperature. Use it when a homework problem gives a Curie constant, when a lab note needs a quick susceptibility check, when you want to compare two temperatures under the same field, or when you need a transparent magnetization estimate before plotting data. The calculator is built for the simple Curie-law regime, not for ordered ferromagnets or full material characterization.

  • Physics homework: Check χ = C/T and M = χH arithmetic without losing track of kelvin temperature.
  • Lab notebooks: Convert a trial Curie constant, temperature, and applied H field into a readable magnetization estimate.
  • Temperature comparisons: Hold C and H fixed while changing T to see the inverse-temperature trend.
  • Plot preparation: Use the inverse-susceptibility output as a quick check for 1/χ versus T work.

Curie’s law is most useful when a material behaves like a collection of weakly interacting magnetic moments. In that setting, heating the sample makes moment alignment harder, so susceptibility drops as temperature rises. The output should be read as an estimate from a model, not as proof that a real specimen follows the model over every temperature range.

A good use of the result is a narrow comparison: same material, same field convention, different temperatures. If a room-temperature row and a heated row use the same C and H, the lower susceptibility should belong to the hotter row. If the trend reverses, check whether Celsius was entered, whether C was copied from a different convention, or whether the data is outside the simple paramagnetic range.

Enter a Curie constant that matches the susceptibility convention being used. This page uses the SI teaching form M = χH, with H in amperes per meter and a dimensionless volume susceptibility χ. If the source gives magnetic flux density B in teslas instead, convert the field convention before comparing numbers.

If the material constant is the missing input, the Curie Constant Calculator helps estimate C before you apply this temperature relationship.

How Curies Law Calculator Works

The calculator applies Curie’s law in two short steps: first compute susceptibility from the material constant and temperature, then multiply by the applied magnetic field strength.

χ = C / T; M = χH = (C / T)H
  • χ: Magnetic susceptibility in the Curie-law model. It is dimensionless in this H-field version.
  • C: Curie constant for the material, entered in kelvins for this susceptibility convention.
  • T: Absolute thermodynamic temperature in kelvins. Celsius values must be converted first.
  • H: Applied magnetic field strength in amperes per meter.
  • M: Magnetization estimate in amperes per meter.

The inverse-susceptibility output is included because Curie-law data is often reviewed by plotting 1/χ against temperature. A simple Curie-law material gives a straight trend through the origin when the assumptions hold. If a measured inverse-susceptibility line has a shifted intercept, the Curie-Weiss model may be a better description.

The Celsius value is only a readability check. The formula itself uses kelvins because temperature appears in a denominator and must be measured from absolute zero.

For a quick reasonableness check, keep the proportional relationships in view. Doubling H doubles M but leaves χ unchanged. Doubling C doubles both χ and M at the same temperature. Doubling T halves χ and M when C and H stay fixed. These checks are often faster than redoing every arithmetic step.

Room-temperature example

Use C = 1.3 K, T = 293.15 K, and H = 1000 A/m.

χ = 1.3 / 293.15 = 0.004435; M = 0.004435 × 1000 = 4.435 A/m.

The calculator returns magnetization of about 4.435 A/m and inverse susceptibility of about 225.5.

At the same applied field, raising T would lower χ and therefore lower M.

According to Communications Physics, magnetic susceptibility relates magnetization to applied field by M = χH, and this linear relation is most valid at high temperatures and low fields.

When your field data is reported through material permeability, the Magnetic Permeability Calculator gives the neighboring magnetic-property view before you enter H here.

Key Concepts Explained

These four ideas keep the result interpretable and help prevent common unit or model mistakes.

Paramagnetism

A paramagnetic material has magnetic moments that tend to align with an applied field, but thermal motion works against that alignment. Curie’s law describes this weak alignment in a simplified range.

Susceptibility

Susceptibility measures response per unit applied field. In this calculator, χ is C divided by absolute temperature, so it falls when T rises and C stays fixed.

Curie constant

The Curie constant summarizes the material side of the model. A larger C produces larger susceptibility at the same temperature, so the material magnetizes more strongly under the same H field.

Inverse plot

Many courses and labs plot 1/χ against T. Curie’s law predicts a linear relationship, which makes the inverse-susceptibility output useful for checking table entries.

The calculator does not infer the Curie constant from atomic structure. That is a separate task involving magnetic moments, number density, and unit conventions. Here, C is treated as an input so the temperature relationship and the magnetization response stay visible.

Be careful with symbol reuse. Some references write Curie-law magnetization with B in teslas and package the magnetic constant differently. This page uses H in A/m so that χ remains dimensionless in the displayed formula.

Also separate volume susceptibility from molar susceptibility. A chemistry table may quote a molar value, while a magnetism exercise may expect a dimensionless volume response. The symbols can look similar even when the units and scaling are not interchangeable.

For particle-level context behind a paramagnetic response, the Magnetic Moment Calculator connects the macroscopic susceptibility result to magnetic moment inputs.

How to Use This Calculator

Use the curies law calculator output as a model check: keep values in one unit convention, then read the result beside the assumptions.

  1. 1 Enter the Curie constant: Use the C value from your problem statement, data fit, or material note. For this page, use kelvins.
  2. 2 Enter absolute temperature: Type temperature in K. For room temperature, 20 °C becomes 293.15 K.
  3. 3 Enter applied field strength: Use H in A/m. If your instrument reports B in teslas, convert the field convention before using this model.
  4. 4 Set rounding: Choose enough displayed decimals to preserve small susceptibility values without making the result hard to read.
  5. 5 Compare scenarios: Change one input at a time, especially T, to see how the inverse-temperature dependence moves the magnetization result.

For C = 0.75 K, T = 300 K, and H = 500 A/m, the calculator gives χ = 0.0025 and M = 1.25 A/m. If the temperature is doubled while C and H stay fixed, χ and M are cut in half.

When copying results into a report, include the original inputs beside the output. A value such as M = 1.25 A/m is only meaningful when the reader can see C = 0.75 K, T = 300 K, H = 500 A/m, and the assumption that the calculation used the H-field susceptibility form.

When temperature is the part you are testing, the Boltzmann Factor Calculator shows how thermal energy changes state weighting in related physics problems.

Benefits of Using This Calculator

A focused Curie-law worksheet is useful because the arithmetic is simple but the interpretation is easy to mix up.

  • Keeps kelvin visible: The temperature conversion output helps catch accidental Celsius entries before they distort the denominator.
  • Separates χ and M: You can see whether a change comes from the material-temperature ratio or from the applied field value.
  • Supports lab tables: The inverse-susceptibility output gives a ready check column for 1/χ versus T plots.
  • Clarifies field convention: The input label uses H in A/m so the result can be compared with M = χH notes.
  • Speeds scenario checks: Changing only T, C, or H makes the proportional and inverse relationships obvious without rebuilding the formula each time.

Use the output to check arithmetic, choose sensible plot columns, or compare conditions in a controlled way. If the result is being compared with measured susceptibility, keep demagnetizing effects, sample shape, background diamagnetism, and instrument calibration outside this simplified calculation.

The calculator is also a useful teaching aid because it exposes the two separate ideas in Curie’s law: material response is bundled into C, while thermal agitation is represented by the inverse dependence on T.

It also helps catch scale mistakes before they enter a graph. A susceptibility around 0.004 and an inverse susceptibility around 250 are consistent with each other; a table that shows both values moving in the same direction after a temperature change should be checked before plotting.

If the same lab report also tracks thermal behavior in gases, the Gas Laws Calculator keeps temperature-unit checks in a familiar physics workflow.

Factors That Affect Your Results

The result depends strongly on assumptions that are easy to overlook in real magnetic measurements.

Temperature scale

Use kelvins. Entering 20 instead of 293.15 for room temperature would make susceptibility far too large.

Field range

The linear relation M = χH is a weak-field approximation. Strong fields can push a material toward saturation.

Magnetic interactions

Curie’s law assumes weakly interacting moments. Strong ferro-, ferri-, or antiferromagnetic interactions can shift the behavior.

Material constant

The Curie constant must match the sample, molar or volume convention, and unit system used by the rest of the calculation.

Background signals

Measured susceptibility can include sample holder, core diamagnetism, or temperature-independent terms not represented here.

  • This calculator is not a Curie-Weiss fit and does not estimate an intercept temperature θ. Use it only for the θ = 0 Curie-law form.
  • It does not model saturation at low temperature or high applied field, so do not use it to predict maximum magnetization.
  • It does not replace experimental corrections for sample geometry, demagnetizing fields, or instrument background.

If a measured 1/χ line is not close to linear, the issue may be physical rather than arithmetic. Interactions, mixed phases, orbital terms, or a poor temperature range can all make a simple Curie-law calculation look inconsistent with data.

For classroom work, record the convention beside every number: C in K for this page, T in K, H in A/m, χ without units, and M in A/m. That short note prevents most comparison errors.

For experiments, treat the output as a starting estimate. Sample holders, diamagnetic backgrounds, calibration drift, and demagnetizing fields can change a fitted Curie constant. The simple calculation is still useful, but it should not be the final evidence for a material assignment.

According to Encyclopaedia Britannica, Curie’s law states that magnetic susceptibility is inversely proportional to absolute temperature, χ = C/T.

According to BIPM, the kelvin, symbol K, is the SI unit of thermodynamic temperature and is defined through the fixed numerical value of the Boltzmann constant.

When the assigned problem uses a dipole model instead of bulk susceptibility, the Magnetic Dipole Moment Calculator keeps that microscopic quantity separate from this Curie-law estimate.

curies law calculator showing susceptibility and magnetization from temperature
curies law calculator showing susceptibility and magnetization from temperature

Frequently Asked Questions

Q: What does this Curie law calculator calculate?

It calculates magnetic susceptibility from χ = C/T and then estimates magnetization from M = χH. The inputs are Curie constant, absolute temperature in kelvins, and applied magnetic field strength H in amperes per meter.

Q: What is the formula for Curie’s law?

The calculator uses χ = C/T for susceptibility and M = χH for magnetization. C is the Curie constant, T is absolute temperature, H is applied field strength, χ is susceptibility, and M is magnetization.

Q: Why does the temperature input use kelvins?

Curie’s law divides by absolute thermodynamic temperature. Kelvin starts from absolute zero, so it is the correct temperature scale for this formula. A Celsius entry would make the denominator physically wrong.

Q: Does Curie’s law use B or H for the magnetic field?

Textbooks commonly write the SI susceptibility relation as M = χH. Some calculator examples use B in teslas with a different bundled constant. This page uses H in A/m so χ remains dimensionless.

Q: When is Curie’s law a poor approximation?

It can fail at low temperatures, strong applied fields, near magnetic ordering transitions, or when magnetic moments interact strongly. Those cases may need saturation models, Curie-Weiss fitting, or direct experimental analysis.

Q: How is Curie’s law different from Curie-Weiss law?

Curie’s law uses χ = C/T. Curie-Weiss law uses χ = C/(T - θ), adding an intercept temperature that represents magnetic interactions. If θ is not near zero, this simpler calculator is not enough.