How is primer Tm estimated?

For sequences under 14 nucleotides, the calculator uses the Wallace rule. For 14–50 nucleotides, it uses a basic salt-adjusted empirical equation. These estimates do not replace nearest-neighbor assay-design software.

How do you calculate a physical melting point?

Melting points of pure elements and compounds are experimentally measured physical constants rather than calculated from a simple formula. Mixtures and alloys usually melt over a solidus-to-liquidus range.

What is the difference between melting point and melting temperature?

Melting point and melting temperature refer to the same physical property: the temperature at which a solid transitions to a liquid at standard atmospheric pressure (1 atm). For pure elements and compounds, it equals the freezing point.

How accurate are the values in this table?

Values are taken from standard chemistry references (NIST, CRC Handbook). Melting points can vary slightly due to purity, pressure, and measurement method, so treat them as reference values rather than exact laboratory measurements.

How do I convert Celsius to Kelvin?

Add 273.15 to the Celsius value. For example, 0 °C = 273.15 K, and 1064 °C (gold) = 1337.15 K. The tool performs this conversion automatically.

Why do metals have such high melting points compared to organic substances?

Metals are held together by metallic bonds — a "sea" of delocalized electrons — which require a lot of energy to break. Organic substances like wax or sugar are held by weaker intermolecular forces, so they melt at much lower temperatures.

Can I look up alloys in this tool?

Yes. The table includes common alloys such as steel, brass, bronze, solder, and several aluminum and titanium alloys, alongside pure elements and compounds.

Does atmospheric pressure affect the melting point?

Yes, but only significantly at very high pressures. For most practical purposes at or near 1 atm, the values listed are accurate. Ice is a notable exception — its melting point decreases slightly under high pressure.

Melting Temperature Calculator

Calculate DNA primer melting temperature, GC content and an annealing-temperature starting point, or switch to the metals and substances melting-point reference.

Primer sequence

DNA sequence (ACGT only) Monovalent salt concentration (mM)

For oligos under 14 nt, the Wallace rule is used. For 14–50 nt, this tool uses a basic salt-adjusted empirical formula. It does not model Mg²⁺, primer concentration, mismatches or secondary structure; use validated assay software for final PCR conditions.

Primer metrics

Enter a DNA primer sequence to calculate metrics.

Search Substances

Showing all 82 substances

Display Unit

Quick Converter

Enter temperature in °C

Fahrenheit

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Kelvin

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Melting Point Reference Table

°C

Substance	Category	Melting Point (°C)

Reference values are approximate at 1 atm. Alloys, waxes and mixtures commonly melt across a range, while some compounds may decompose before a clean phase transition. Confirm a supplier specification or SDS for safety-critical work.

Summary

Calculate DNA primer melting temperature, GC content and an annealing-temperature starting point, or switch to the metals and substances melting-point reference.

How it works

Choose DNA / Primer Tm or the Substances & Metals reference.
For a primer, enter a 5′ to 3′ ACGT sequence and the monovalent salt concentration.
For a substance, search the reference table and select a row for unit conversions.
Use the unit buttons or custom converter to switch between °C, °F, and K.

Use cases

Estimate primer Tm and an initial PCR annealing-temperature starting point.
Verify a reference melting point before machining or casting.
Compare melting temperatures of different alloys side by side.
Convert a literature melting point from Celsius to Fahrenheit or Kelvin.
Quick reference for chemistry homework or lab prep.
Identify which substances stay solid or liquid at a given process temperature.
Educational demos of the wide range of melting points across the periodic table.

Frequently Asked Questions

Last updated: 2026-09-22 · Reviewed by Nham Vu