This fusion calculator estimates how much theoretical energy could be released from a deuterium-tritium (D-T) fuel mix, then converts that thermal energy into an electricity estimate based on your chosen efficiency. It is designed for education, concept planning, and intuition-building.
What this fusion calculator does
The model uses the well-known D-T fusion reaction: D + T → He-4 + n + 17.6 MeV. You enter the available fuel mass and two efficiency assumptions. The calculator then estimates:
- How many reactions can happen (limited by the smaller reactant amount).
- Total thermal fusion energy in joules.
- Equivalent electrical energy in kWh.
- Approximate TNT-equivalent thermal energy.
- Optional electricity value based on a market price input.
Input guide
1) Deuterium and tritium mass
The reaction consumes one deuterium nucleus and one tritium nucleus per fusion event. If one fuel is in short supply, it becomes the limiting reactant and caps total reactions.
2) Fuel burned (%)
Not all available fuel will react. Burnup captures this reality. If you set burnup to 80%, the calculator assumes only 80% of theoretically possible reactions actually occur.
3) Conversion efficiency (%)
Fusion initially releases thermal energy. Power plants convert only a fraction of heat into electricity. This input controls that step.
4) Electricity value ($/kWh)
This optional field multiplies electric output by price to estimate gross energy value. It does not include capital cost, maintenance, fuel processing, financing, or transmission losses.
How the math works
Under the hood, the calculator uses standard constants and basic stoichiometry:
- Molar mass of deuterium: 2.014 g/mol
- Molar mass of tritium: 3.016 g/mol
- Avogadro's number: 6.02214076 × 1023 particles/mol
- Energy per D-T reaction: 17.6 MeV
- 1 eV = 1.602176634 × 10-19 J
It calculates moles of each isotope, identifies the limiting side, scales by burnup, and then computes total energy. Finally, it converts joules to kWh by dividing by 3.6 million.
Interpreting your result responsibly
Fusion energy density is enormous, so even small input masses can produce very large theoretical numbers. That does not mean practical net-electric operation is easy. In real systems, a meaningful portion of generated energy supports plasma heating, magnet systems, cryogenics, pumping, fuel handling, shielding, and control systems.
Use this tool to compare scenarios, not to claim deployable plant economics.
Best use cases for this calculator
- Classroom demonstrations of fusion reaction scale.
- Early-stage educational research notes.
- Back-of-the-envelope comparisons with fission and fossil systems.
- Explaining limiting reactants in high-energy physics contexts.
FAQ
Why D-T fusion?
D-T has one of the most favorable reaction cross-sections at achievable plasma temperatures, making it the most studied near-term pathway.
Does this include Bremsstrahlung and transport losses?
No. Those losses are folded only indirectly into your burnup and conversion assumptions.
Is this calculator for weapon design?
No. It is a high-level educational estimator using publicly known constants and simplified power-conversion logic.
Final takeaway
Fusion is a fascinating blend of plasma physics, materials science, and power engineering. A simple calculator like this can sharpen intuition: tiny fuel masses can hold huge energy potential, but practical extraction depends on sophisticated and efficient reactor design.