Benchmark

Performance figures for fusion devices. Every gain value states what was counted as input, because without that a gain number does not mean anything.

Why denominators are not a detail

These two rows describe the same facility, on the same shot (N221204). They differ by a factor of 536 — entirely because of what each counts as energy in. Both are true. They answer different questions, and only one of them is the question a power plant has to answer. The smaller figure is itself an upper bound: its denominator is the laser capacitor bank, not the whole facility.

4.13 Q_target

Denominator
Laser energy delivered to the target, including hohlraum losses

1.5 Q_target

Denominator
Laser energy delivered to the target, including hohlraum losses

0.0077 Wall-plug gain

Denominator
Total facility grid energy drawn for the shot

Achieved

3 measurements

Measured on a shot, with a date. The only tier eligible for a leaderboard.

Achieved measurements
Device	Metric	Value	Unit	Date	Source
National Ignition Facility N221204	Q_target per laser energy delivered to the target, including hohlraum losses	1.5		2022-12-05	Achievement of Target Gain Larger than Unity in an Inertial Fusion Experiment
National Ignition Facility N221204	Fusion energy yield	3.1	MJ	2022-12-05	Achievement of Target Gain Larger than Unity in an Inertial Fusion Experiment
National Ignition Facility N221204	Laser energy on target	2.05	MJ	2022-12-05	Achievement of Target Gain Larger than Unity in an Inertial Fusion Experiment

Claimed

92 measurements

Asserted, not independently confirmed. Published and labelled, not treated as established.

Claimed measurements
Device	Metric	Value	Unit	Date	Source
Joint European Torus	Fusion energy yield	69.26	MJ	2023-10	JET Tokamak’s Latest Fusion Energy Record Shows Mastery of Fusion Processes
JT-60U	nTτ	3.1 × 10²⁰	m⁻³·keV·s	—	Overview of JT-60U Results toward High Integrated Performance in Reactor-Relevant Regime
JT-60U	Ion temperature	21.5	keV	—	Overview of JT-60U Results toward High Integrated Performance in Reactor-Relevant Regime
JT-60U	Plasma density	4.2 × 10¹⁹	m⁻³	—	Overview of JT-60U Results toward High Integrated Performance in Reactor-Relevant Regime
JT-60U	Energy confinement time (τ_E)	0.344	s	—	Overview of JT-60U Results toward High Integrated Performance in Reactor-Relevant Regime
JT-60U	Equivalent D-T gain (extrapolated) per external heating power coupled into the plasma	0.185		—	Overview of JT-60U Results toward High Integrated Performance in Reactor-Relevant Regime
KSTAR	Ion temperature (sustained)	8.6	keV	2024-03	Green light on continuous fusion plasma operations technology
T-3 H_{z}=25 kOe, I_{z}=85 kA discharges	nTτ	2 × 10¹⁶	m⁻³·keV·s	1969	Continuing progress toward fusion energy breakeven and gain as measured against the Lawson criteria
T-3 H_{z}=25 kOe, I_{z}=85 kA discharges	Ion temperature	0.3	keV	1969	Continuing progress toward fusion energy breakeven and gain as measured against the Lawson criteria
T-3 H_{z}=25 kOe, I_{z}=85 kA discharges	Plasma density	2.25 × 10¹⁹	m⁻³	1969	Continuing progress toward fusion energy breakeven and gain as measured against the Lawson criteria
T-3 H_{z}=25 kOe, I_{z}=85 kA discharges	Energy confinement time (τ_E)	0.003	s	1969	Continuing progress toward fusion energy breakeven and gain as measured against the Lawson criteria
ST 12cm limiter	nTτ	2.4 × 10¹⁷	m⁻³·keV·s	1972	Continuing progress toward fusion energy breakeven and gain as measured against the Lawson criteria
ST 12cm limiter	Ion temperature	0.4	keV	1972	Continuing progress toward fusion energy breakeven and gain as measured against the Lawson criteria
ST 12cm limiter	Plasma density	6 × 10¹⁹	m⁻³	1972	Continuing progress toward fusion energy breakeven and gain as measured against the Lawson criteria
ST 12cm limiter	Energy confinement time (τ_E)	0.01	s	1972	Continuing progress toward fusion energy breakeven and gain as measured against the Lawson criteria
TFR Iconel limiter	nTτ	5.2 × 10¹⁸	m⁻³·keV·s	1981	Continuing progress toward fusion energy breakeven and gain as measured against the Lawson criteria
TFR Iconel limiter	Ion temperature	0.95	keV	1981	Continuing progress toward fusion energy breakeven and gain as measured against the Lawson criteria
TFR Iconel limiter	Plasma density	1.61 × 10²⁰	m⁻³	1981	Continuing progress toward fusion energy breakeven and gain as measured against the Lawson criteria
TFR Iconel limiter	Energy confinement time (τ_E)	0.034	s	1981	Continuing progress toward fusion energy breakeven and gain as measured against the Lawson criteria
PLT 22149-231	nTτ	3.2 × 10¹⁸	m⁻³·keV·s	1976	Continuing progress toward fusion energy breakeven and gain as measured against the Lawson criteria
PLT 22149-231	Ion temperature	1.54	keV	1976	Continuing progress toward fusion energy breakeven and gain as measured against the Lawson criteria
PLT 22149-231	Plasma density	5.2 × 10¹⁹	m⁻³	1976	Continuing progress toward fusion energy breakeven and gain as measured against the Lawson criteria
PLT 22149-231	Energy confinement time (τ_E)	0.04	s	1976	Continuing progress toward fusion energy breakeven and gain as measured against the Lawson criteria
Alcator A 8.7T discharge	nTτ	2.4 × 10¹⁹	m⁻³·keV·s	1978	Continuing progress toward fusion energy breakeven and gain as measured against the Lawson criteria
Alcator A 8.7T discharge	Ion temperature	0.8	keV	1978	Continuing progress toward fusion energy breakeven and gain as measured against the Lawson criteria
Alcator A 8.7T discharge	Plasma density	1.5 × 10²¹	m⁻³	1978	Continuing progress toward fusion energy breakeven and gain as measured against the Lawson criteria
Alcator A 8.7T discharge	Energy confinement time (τ_E)	0.02	s	1978	Continuing progress toward fusion energy breakeven and gain as measured against the Lawson criteria
Alcator C Multiple pellet injection	nTτ	1.2 × 10²⁰	m⁻³·keV·s	1984	Continuing progress toward fusion energy breakeven and gain as measured against the Lawson criteria
Alcator C Multiple pellet injection	Ion temperature	1.5	keV	1984	Continuing progress toward fusion energy breakeven and gain as measured against the Lawson criteria
Alcator C Multiple pellet injection	Plasma density	1.5 × 10²¹	m⁻³	1984	Continuing progress toward fusion energy breakeven and gain as measured against the Lawson criteria
Alcator C Multiple pellet injection	Energy confinement time (τ_E)	0.052	s	1984	Continuing progress toward fusion energy breakeven and gain as measured against the Lawson criteria
ASDEX 23349-57	nTτ	7.2 × 10¹⁸	m⁻³·keV·s	1988	Continuing progress toward fusion energy breakeven and gain as measured against the Lawson criteria
ASDEX 23349-57	Ion temperature	0.8	keV	1988	Continuing progress toward fusion energy breakeven and gain as measured against the Lawson criteria
ASDEX 23349-57	Energy confinement time (τ_E)	0.12	s	1988	Continuing progress toward fusion energy breakeven and gain as measured against the Lawson criteria
Joint European Torus 26087	nTτ	6.1 × 10²⁰	m⁻³·keV·s	1991-11-02	Continuing progress toward fusion energy breakeven and gain as measured against the Lawson criteria
Joint European Torus 26087	Ion temperature	18.6	keV	1991-11-02	Continuing progress toward fusion energy breakeven and gain as measured against the Lawson criteria
Joint European Torus 26087	Plasma density	4.1 × 10¹⁹	m⁻³	1991-11-02	Continuing progress toward fusion energy breakeven and gain as measured against the Lawson criteria
Joint European Torus 26087	Energy confinement time (τ_E)	0.8	s	1991-11-02	Continuing progress toward fusion energy breakeven and gain as measured against the Lawson criteria
Tokamak Fusion Test Reactor 83546	nTτ	7.9 × 10²⁰	m⁻³·keV·s	1995-02-17	Continuing progress toward fusion energy breakeven and gain as measured against the Lawson criteria
Tokamak Fusion Test Reactor 83546	Ion temperature	43	keV	1995-02-17	Continuing progress toward fusion energy breakeven and gain as measured against the Lawson criteria
Tokamak Fusion Test Reactor 83546	Plasma density	6.6 × 10¹⁹	m⁻³	1995-02-17	Continuing progress toward fusion energy breakeven and gain as measured against the Lawson criteria
Tokamak Fusion Test Reactor 83546	Energy confinement time (τ_E)	0.28	s	1995-02-17	Continuing progress toward fusion energy breakeven and gain as measured against the Lawson criteria
JT-60U E31872	nTτ	5.6 × 10²⁰	m⁻³·keV·s	1998	Continuing progress toward fusion energy breakeven and gain as measured against the Lawson criteria
JT-60U E31872	Ion temperature	16.8	keV	1998	Continuing progress toward fusion energy breakeven and gain as measured against the Lawson criteria
JT-60U E31872	Plasma density	4.8 × 10¹⁹	m⁻³	1998	Continuing progress toward fusion energy breakeven and gain as measured against the Lawson criteria
JT-60U E31872	Energy confinement time (τ_E)	0.69	s	1998	Continuing progress toward fusion energy breakeven and gain as measured against the Lawson criteria
DIII-D 87977	nTτ	3.7 × 10²⁰	m⁻³·keV·s	1997	Continuing progress toward fusion energy breakeven and gain as measured against the Lawson criteria
DIII-D 87977	Ion temperature	18.1	keV	1997	Continuing progress toward fusion energy breakeven and gain as measured against the Lawson criteria
DIII-D 87977	Plasma density	8.5 × 10¹⁹	m⁻³	1997	Continuing progress toward fusion energy breakeven and gain as measured against the Lawson criteria
DIII-D 87977	Energy confinement time (τ_E)	0.24	s	1997	Continuing progress toward fusion energy breakeven and gain as measured against the Lawson criteria
START 35533	nTτ	6.1 × 10¹⁶	m⁻³·keV·s	1998	Continuing progress toward fusion energy breakeven and gain as measured against the Lawson criteria
START 35533	Ion temperature	0.2	keV	1998	Continuing progress toward fusion energy breakeven and gain as measured against the Lawson criteria
START 35533	Energy confinement time (τ_E)	0.003	s	1998	Continuing progress toward fusion energy breakeven and gain as measured against the Lawson criteria
MAST 14626	nTτ	4.5 × 10¹⁸	m⁻³·keV·s	2006	Continuing progress toward fusion energy breakeven and gain as measured against the Lawson criteria
MAST 14626	Ion temperature	3	keV	2006	Continuing progress toward fusion energy breakeven and gain as measured against the Lawson criteria
MAST 14626	Plasma density	3 × 10¹⁹	m⁻³	2006	Continuing progress toward fusion energy breakeven and gain as measured against the Lawson criteria
MAST 14626	Energy confinement time (τ_E)	0.05	s	2006	Continuing progress toward fusion energy breakeven and gain as measured against the Lawson criteria
NSTX 129041	nTτ	4.8 × 10¹⁸	m⁻³·keV·s	2009	Continuing progress toward fusion energy breakeven and gain as measured against the Lawson criteria
NSTX 129041	Ion temperature	1.2	keV	2009	Continuing progress toward fusion energy breakeven and gain as measured against the Lawson criteria
NSTX 129041	Plasma density	5 × 10¹⁹	m⁻³	2009	Continuing progress toward fusion energy breakeven and gain as measured against the Lawson criteria
NSTX 129041	Energy confinement time (τ_E)	0.08	s	2009	Continuing progress toward fusion energy breakeven and gain as measured against the Lawson criteria
Experimental Advanced Superconducting Tokamak 56933	nTτ	9.6 × 10¹⁸	m⁻³·keV·s	2015	Continuing progress toward fusion energy breakeven and gain as measured against the Lawson criteria
Experimental Advanced Superconducting Tokamak 56933	Ion temperature	2.1	keV	2015	Continuing progress toward fusion energy breakeven and gain as measured against the Lawson criteria
Experimental Advanced Superconducting Tokamak 56933	Plasma density	8.5 × 10¹⁹	m⁻³	2015	Continuing progress toward fusion energy breakeven and gain as measured against the Lawson criteria
Experimental Advanced Superconducting Tokamak 56933	Energy confinement time (τ_E)	0.054	s	2015	Continuing progress toward fusion energy breakeven and gain as measured against the Lawson criteria
KSTAR 7081	nTτ	9.6 × 10¹⁸	m⁻³·keV·s	2014	Continuing progress toward fusion energy breakeven and gain as measured against the Lawson criteria
KSTAR 7081	Ion temperature	2	keV	2014	Continuing progress toward fusion energy breakeven and gain as measured against the Lawson criteria
KSTAR 7081	Energy confinement time (τ_E)	0.1	s	2014	Continuing progress toward fusion energy breakeven and gain as measured against the Lawson criteria
C-Mod 1160930033	nTτ	7.4 × 10¹⁹	m⁻³·keV·s	2016	Continuing progress toward fusion energy breakeven and gain as measured against the Lawson criteria
C-Mod 1160930033	Ion temperature	2.5	keV	2016	Continuing progress toward fusion energy breakeven and gain as measured against the Lawson criteria
C-Mod 1160930033	Plasma density	5.5 × 10²⁰	m⁻³	2016	Continuing progress toward fusion energy breakeven and gain as measured against the Lawson criteria
C-Mod 1160930033	Energy confinement time (τ_E)	0.054	s	2016	Continuing progress toward fusion energy breakeven and gain as measured against the Lawson criteria
ASDEX UPGRADE 32305	nTτ	2.2 × 10¹⁹	m⁻³·keV·s	2016	Continuing progress toward fusion energy breakeven and gain as measured against the Lawson criteria
ASDEX UPGRADE 32305	Ion temperature	8	keV	2016	Continuing progress toward fusion energy breakeven and gain as measured against the Lawson criteria
ASDEX UPGRADE 32305	Plasma density	5 × 10¹⁹	m⁻³	2016	Continuing progress toward fusion energy breakeven and gain as measured against the Lawson criteria
ASDEX UPGRADE 32305	Energy confinement time (τ_E)	0.056	s	2016	Continuing progress toward fusion energy breakeven and gain as measured against the Lawson criteria
GLOBUS-M2 37873	nTτ	1.4 × 10¹⁸	m⁻³·keV·s	2019	Continuing progress toward fusion energy breakeven and gain as measured against the Lawson criteria
GLOBUS-M2 37873	Ion temperature	1.2	keV	2019	Continuing progress toward fusion energy breakeven and gain as measured against the Lawson criteria
GLOBUS-M2 37873	Energy confinement time (τ_E)	0.01	s	2019	Continuing progress toward fusion energy breakeven and gain as measured against the Lawson criteria
ST40 10009	nTτ	6.3 × 10¹⁸	m⁻³·keV·s	2022	Continuing progress toward fusion energy breakeven and gain as measured against the Lawson criteria
ST40 10009	Ion temperature	9.6	keV	2022	Continuing progress toward fusion energy breakeven and gain as measured against the Lawson criteria
ST40 10009	Plasma density	5.5 × 10¹⁹	m⁻³	2022	Continuing progress toward fusion energy breakeven and gain as measured against the Lawson criteria
ST40 10009	Energy confinement time (τ_E)	0.012	s	2022	Continuing progress toward fusion energy breakeven and gain as measured against the Lawson criteria
Joint European Torus 42976	Q_plasma per external heating power coupled into the plasma	0.63		1997-10-31	Continuing progress toward fusion energy breakeven and gain as measured against the Lawson criteria
Tokamak Fusion Test Reactor 76778	Q_plasma per external heating power coupled into the plasma	0.28		1994-05-27	Continuing progress toward fusion energy breakeven and gain as measured against the Lawson criteria
National Ignition Facility N250406	Q_target per laser energy delivered to the target, including hohlraum losses	4.13		2025-04-07	Continuing progress toward fusion energy breakeven and gain as measured against the Lawson criteria
OMEGA 103952	Q_target per laser energy delivered to the target, including hohlraum losses	0.03		2022-04-14	Continuing progress toward fusion energy breakeven and gain as measured against the Lawson criteria
National Ignition Facility N221204	Wall-plug gain per total facility grid energy drawn for the shot	0.0077		2022-12-05	Power Conditioning System
Tokamak Fusion Test Reactor	Ion temperature	5.1 × 10⁸	K	—	Tokamak Fusion Test Reactor
Wendelstein 7-X	nTτ	6 × 10²⁶	K·m⁻³·s	2018-06	Wendelstein 7-X attains world record for fusion product
Wendelstein 7-X	Ion temperature	4 × 10⁷	K	2018-06	Wendelstein 7-X attains world record for fusion product
Wendelstein 7-X	Plasma density	8 × 10¹⁹	m⁻³	2018-06	Wendelstein 7-X attains world record for fusion product

Planned

10 measurements

Design targets and roadmap goals. Never ranked against the figures above — a 2030 target and a 2022 measurement are not comparable quantities.

Planned measurements
Device	Metric	Value	Unit	Date	Source
ITER	Q_plasma per external heating power coupled into the plasma	10		—	The machine
SPARC Projected	nTτ	6.2 × 10²¹	m⁻³·keV·s	—	Continuing progress toward fusion energy breakeven and gain as measured against the Lawson criteria
SPARC Projected	Ion temperature	20	keV	—	Continuing progress toward fusion energy breakeven and gain as measured against the Lawson criteria
SPARC Projected	Plasma density	4 × 10²⁰	m⁻³	—	Continuing progress toward fusion energy breakeven and gain as measured against the Lawson criteria
SPARC Projected	Energy confinement time (τ_E)	0.77	s	—	Continuing progress toward fusion energy breakeven and gain as measured against the Lawson criteria
ITER Projected	nTτ	7.4 × 10²¹	m⁻³·keV·s	—	Continuing progress toward fusion energy breakeven and gain as measured against the Lawson criteria
ITER Projected	Ion temperature	20	keV	—	Continuing progress toward fusion energy breakeven and gain as measured against the Lawson criteria
ITER Projected	Plasma density	10²⁰	m⁻³	—	Continuing progress toward fusion energy breakeven and gain as measured against the Lawson criteria
ITER Projected	Energy confinement time (τ_E)	3.7	s	—	Continuing progress toward fusion energy breakeven and gain as measured against the Lawson criteria
SPARC	Q_plasma per external heating power coupled into the plasma	2		—	SPARC: Proving commercial fusion energy is possible \| Commonwealth Fusion Systems

Device design parameters

Major radius, plasma current, magnetic field and pulse length are properties of how a machine was built, not results it achieved. 338 such figures are recorded across 78 devices and are compared on the devices page, deliberately kept off this one.

The gain metrics

There is no general “gain” field in this dataset. It exists only in these denominated forms, so an undenominated figure cannot be recorded at all.

Target gain (Q_target): Out: Total fusion energy yield of the implosion · In: Laser energy delivered to the target, including hohlraum losses
Equivalent D-T gain (extrapolated): Out: Modelled D-T fusion power · In: External heating power coupled into the plasma
Plasma gain (Q_plasma): Out: Fusion power produced · In: External heating power coupled into the plasma
Wall-plug gain: Out: Total fusion energy yield · In: Total facility grid energy drawn for the shot