Weathering Rate Calculator

Measure dissolution using lab masses or stream chemistry. Choose units, correct temperature, and compare scenarios. Download tables, keep notes, and share clear outputs today.

Calculator

Pick the measurement approach you have.
Geometric area in contact with water or air.
Multiplies geometric area to estimate reactive area.
Measurement interval for your experiment or observation.
Optional correction for comparing rates at one temperature.
Temperature during the observation.
Common choice: 25 °C.
Typical ranges: 30–80 kJ/mol (varies by system).
Starting dry mass of the specimen.
Ending dry mass after exposure.
Subtract non-weathering loss (handling/cleaning).
Use solute concentration above background if applicable.
Needed for mg/L → mol/L conversion.
Flow rate through the reacting volume or outlet.
Mineral moles per solute mole (default 1).
Measured lowering or recession over the interval.
Used to estimate mass loss from thickness change.

Example data table

Method Area Time Key input Example output
Mass-loss 0.10 m² 7 days 100 g → 98.2 g ~9.386 g/m²/yr
Solute-flux 2.00 m² 1 day 25 mg/L, 1.2 L/s ~0.0000025 mol/m²/s
Retreat 1.00 m² 2 years 0.35 mm, 2.65 g/cm³ ~0.175 mm/yr

These are illustrative examples. Use your own measurements for meaningful results.

Formula used

Effective reactive area: Aeff = A × frough

Mass-loss method: Loss = (minitial − mfinal) − mblank, Rate = Loss ÷ (Aeff × t)

Solute-flux method: Fluxsolute = C × Q, Rate = (Fluxsolute × s) ÷ Aeff where s is a stoichiometric factor.

Thickness retreat method: Rateretreat = Δh ÷ t, mass rate uses ρ: Ratemass = (ρ × Δh) ÷ t.

Arrhenius normalization (optional): k(Tref) = k(T) × exp( −Ea/R × (1/Tref − 1/T) ) (temperatures in kelvin).

How to use this calculator

  1. Select the method that matches your measurements.
  2. Enter surface area, roughness factor, and duration.
  3. Fill in the method-specific fields shown below.
  4. Optional: enable Arrhenius normalization to a reference temperature.
  5. Press Calculate to display results above the form.
  6. Use the download buttons to export CSV or PDF.

Why weathering rate is tracked

Weathering rate links mineral breakdown to water chemistry, soil evolution, and carbon cycling. It is also used to evaluate nutrient release and contaminant mobility from solids exposed to water. In laboratories it supports tests for stone, glass, and slags. In catchments it helps compare lithologies and climate regimes. A consistent rate metric lets you benchmark interventions, detect anomalies, and communicate uncertainty to stakeholders.

Choosing a measurement pathway

This calculator supports three common pathways. Mass-loss uses before-and-after dry masses and a blank correction to isolate true material removal. Include replicate coupons when possible to quantify variability and handling losses. Solute-flux converts dissolved concentration and discharge into a molar release rate, then scales by reactive area. Thickness retreat uses measured surface lowering and density to estimate an equivalent mass loss per area, which is useful for polished surfaces and field tablets.

Area handling and unit discipline

Rates are normalized by effective reactive area, not only geometric area. The roughness factor approximates extra microscopic surface created by pores, etch pits, or fractured grains. Use conservative factors when data are limited, and document the choice. Unit conversions are applied automatically so you can enter cm², mm², or m² and obtain comparable outputs. Time is converted to years and seconds to keep both field and lab intervals consistent.

Temperature normalization for comparability

Weathering reactions are temperature sensitive. When you enable Arrhenius normalization, the tool scales measured rates to a chosen reference temperature using an activation energy. This supports side-by-side comparison of experiments performed at different temperatures or seasonal field observations. Choose reference temperature based on your reporting convention and keep it fixed across studies. Use literature values when available, and treat the normalized output as a scenario, not a direct measurement.

Interpreting outputs and reporting

The result table provides multiple units such as g/m²/yr, mg/cm²/day, and mol/m²/s, plus reference-temperature variants. Choose the unit that matches your dataset and reporting standards, then keep the others for cross-checking. Review sign and magnitude to confirm physically plausible loss or flux. Record assumptions: blank loss, stoichiometric factor, molar mass basis, density, and roughness. Exporting CSV and PDF helps preserve inputs and ensures reproducible documentation.

FAQs

What does the roughness factor mean?

It scales geometric area to approximate reactive surface area. Use 1.0 for smooth coupons, and higher values for porous, fractured, or etched surfaces. Document how you estimated it.

When is the solute-flux method appropriate?

Use it when you have dissolved concentration and flow rate for a steady outlet, reactor, or stream reach. Subtract background concentration if needed, then normalize by effective area.

Which molar mass should I enter for mg/L inputs?

Enter the molar mass for the reporting basis of your concentration. For example, use 60.08 for SiO2-as-silica, or 28.085 for Si-as-elemental. Keep the basis consistent.

What is the stoichiometric factor used for?

It converts solute release into mineral equivalents. Set 1.0 if one mole of solute represents one mole of mineral dissolution, or adjust for reaction stoichiometry and chosen tracer species.

How should I use temperature normalization?

Enable Arrhenius normalization to compare rates at a fixed reference temperature. Choose a reference, enter measured temperature and activation energy, and report both measured and normalized values.

Why did the mass-loss rate become zero?

If final mass is higher, or blank correction exceeds loss, the corrected loss becomes negative. The calculator floors loss at zero to avoid misleading rates. Recheck drying, deposits, and blank measurements.

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Important Note: All the Calculators listed in this site are for educational purpose only and we do not guarentee the accuracy of results. Please do consult with other sources as well.