We know that (in the TNG era) Starfleet's photon torpedoes are warp capable warheads, which upon detonation create a very strong matter-antimatter explosion, but what is the strength of this explosion in absolute terms, ie tons of TNT?

BTW, I'm not asking if the strength of the explosion can be adjusted, as we already know this, but what is the equivalent base/reference value in tons of TNT.

Answers based both on canon and EU are acceptable.

Edit: It has been suggested that this question is a dupe with this one. However, the latter explicitly asks about the differences between photon and quantum torpedoes, while I'm asking about the yield, so clearly it's not a dupe.

  • My answer here (on the question you said isn't a dupe) explicitly answers this question. - "According to the DS9 Technical Manual, the explosive force from a Photon torpedo is 18.5 isotons (a fictional measure that doesn't translate directly into megatonnes) with a theoretical upper limit of 25 isotonnes given ideal conditions.
    – Valorum
    Commented Nov 7, 2017 at 20:56
  • In "The Omega Directive", Kim and Tuvok alter a torpedo warhead to an 80 isotonne yield, which seems much higher than that theoretical upper limit.
    – Graham Lee
    Commented Nov 13, 2017 at 18:17

5 Answers 5


A photon torpedo contains 1.5 kg of matter and 1.5 kg of antimatter which yields 64.4 megatons of TNT, that's enough to flatten New York City.

Source - Star Trek: The Next Generation Technical Manual

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    Star Trek: The Next Generation Technical Manual gives the mater and antimater yields of the torpedo, the rest is conversion to megatons using E=mc^2 and you can see the result on Nukemap.
    – Ninja2k
    Commented Nov 7, 2017 at 20:56
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    @Valorum Do you have a source for that?
    – Ninja2k
    Commented Nov 7, 2017 at 21:01
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    @Valorum: How do you get that? They are magnetically confined. I don't think you can cite the lack of an explosion as evidence that ST physics doesn't match Real World physics. Commented Nov 7, 2017 at 21:26
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    You may wish to note that the yield of a matter/antimatter explosion is yielded in a fictional measure (the "isotonne") specifically to avoid any canonical real-world attempts to measure the actual yield (which could then be used to invalidate what we see happening in the episodes).
    – Valorum
    Commented Nov 7, 2017 at 21:31
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    @Mwr247 That is like saying metres is not relevant because you don't have the conversion rate to km, the technical manual is considered canon material, we know from the show that you can increase the yield of photon torpedos the same way you can with nukes, by adding more mater/antimater or adding something else to the torpedo like you can with a nuclear weapon so that is probably the theoretical limit at 1.5kg/1.5kg (An additive or different casing) but my answer is correct.
    – Ninja2k
    Commented Nov 7, 2017 at 21:46

Technical Manuals, although non-canon, state the weapons to be 64 megatons (ST TNG TM). Meanwhile in canon, it is specifically stated that torpedoes have variable yields from "knocking off the comm array off a shuttle without leaving a scratch" to "putting a 300 kilometer crater" in something (ST ENT). Keep in mind, this was before Kirk's time, when the torpedoes were originally called photonic torpedoes. In the episode "The Wolf Inside" (ST DSC) shows torpedoes literally slagging the crust of a planet, making it crack open like an egg, which goes consistent with Star Trek's high yields such as "The Die is Cast"(ST DS9),"Annihilation"(ST TOS), "Skin of Evil" as well as other episodes where the actual high end yields of these weapons go from high gigatons to low teratons.

  • Don't forget the fact that SF (and Trek in general) technology uses subspace extensively. Even though a photon torpedo for example may have 1.5kg of matter and 1.5kg of antimatter (which would provide 64 Megatons yield), due to heavy use of subspace technology, it could easily amplify destructive yields to high gigatons and teratons (depending on the desired effect) - it could also be why Isotonnes are used as opposed to units we use today - because of subspace and how these weapons are highly customisable.
    – Deks
    Commented Aug 6, 2019 at 21:52

The technical manuals aren't canon... and to be honest, it doesn't correspond with on-screen/canon data on technology in question.

From what we observed on-screen, the upper end yields for early TNG photon torpedoes seemed to have been in 500 megaton range. Later on near the end of TNG and also in DS9 we say gigaton ranges.

If you take into account exponential developments in science and technology from the real world, it stands to reason the weapons would be much more powerful nearing the start of the Dominion War, and also by the end of the said war.

In fact, by mid-late TNG, we saw that the Enterprise-D was using a low charge and tightly focused phaser beam to drill into the planets crust... estimated yields were calculated to be about 1.5% of the total phaser output (which would require low gigaton yields).

At maximum, we've seen teraton level outputs (which are not inconsistent with the other shows) coming from Federation, Klingon, Romulan and Cardassian ships in DS9 for example.

Weapons also have excessively long range... phasers in TNG were seen to have at least 150 000 km range, and torpedoes 300 000 km ranges... for the Nebula class.

If the Enterprise-D was remotely comparable (and it stands to reason it was), we need to keep in mind it received upgrades to its shields and weapons which among other things extended their range (and likely firepower).

Furthermore, the 64 megaton yields for photon torpedoes are more in line with Kirk's era (TOS and Enterprise-A).

  • Per my comment earlier, the yields are specifically recorded in isotonnes, a measure that (purposefully) doesn't translate into real figures.
    – Valorum
    Commented Mar 23, 2018 at 20:07
  • Of course that isotonnes do not translate to real figures... I'm talking about extrapolating firepower based on dialogue and what the weapons were used for.
    – Deks
    Commented Mar 25, 2018 at 18:53
  • The depiction is also wildly inconsistent. In some cases they bounce harmlessly off of shields, in other cases they're planet-busters.
    – Valorum
    Commented Mar 25, 2018 at 18:54
  • Phasers on Enterprise-D demonstrated at the very least a tightly focused 10 gigaton output at between 1-10% power output to penetrate 3 000 km of planetary crust (anything more and you risk damaging effects on a planetary scale). It stands to reason that torpedoes at that time would have been in hundreds of gigatons range (Which actually tracks with dialogue at how much planetary area would be affected if torpedoes were fired on a planet in DS9). And 'In the die is cast' we easily witnessed Teraton level yields... which is more on track with how Trek weapons should behave.
    – Deks
    Commented Mar 25, 2018 at 19:02
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    Sorry, but you're just making up numbers. You might as well say "a gajillion" given that the way these weapons work defies normal physics.
    – Valorum
    Commented Mar 25, 2018 at 19:08

As I mentioned above... the technical manuals are NOT considered canon therefore, they cannot be taken at face value.

Also, despite that a photon torpedo is claimed to contain 1.5kg of matter and 1.5kg of anti-matter... it doesn't automatically mean the explosive yield will be 64 Megatons (and no, I am NOT implying it would be lower than that either).

On-screen data is inconsistent at best (as we have examples of both low and high very high yields), but throughout TNG, DS9 and VOY, we've observed effects of both phasers and photon torpeodes as being excessively powerful (in the hundreds of megatons, gigatons and even teratons).

Furthermore, what we need to keep in mind is that all Starfleet hardware (weapons included) use a plethora of subspace based technology. Why is this important? We've seen that subspace technology was applied in every field in Trek. All ships emit subspace signatures for example and use low level subspace field to lower their mass to the point so they can maneuver like small fighters and greatly increase sublight speeds - a prime example of this is DS9 pilot episode in which O'Brien was tasked to create a low level subspace field around the station so the stations orbital/positioning thrusters would get them to the mouth of the wormhole by next day - and even O'Brien mentioned that the station is not a starship, meaning that ships do this all the time - and we've seen them do this). So, it stands to reason that application of subspace technology can explain 'Gigaton' and 'Teraton' level yields from Federation, Klingon, Cardassians and Romulans even.

In short, applying subspace technology to weapons (phasers and photon torpedoes) could conceivably have an effect on energy output and explosive yields, amplifying both to very high levels.

This is something most people seem to ignore even though we witnessed both Phasers and Photon Torpedoes utilizing subspace technology (and considering the feats we saw from both - as well as how they interact with various substances, there's easily enough leeway to explain why the effect would be minimized or enhanced even - the TNG Pegasus episode is quoted as an example of low yields, but we knew nothing about composition of the asteroid in question which could reduce effectiveness of weapons - various substances in Trek can be used to minimize destructive effect of phasers and photon torpeodes).

Also, it doesn't make any sense that 64 Megatons would be the top end yield for 24th century photon torpedo. It would barely make it more powerful than current day nuclear weapon - which simply doesn't keep track with 360-odd years of exponential developments.

We also know that Starfleet weapons are highly customizable and seem to exhibit a shaped charge effect (focusing the energy output or even explosions to a singular point as much as possible - which easily explains why weapons would behave like 'firecrackers' as opposed to produce ridiculous shockwaves all the time). Furthermore, SF could have designed their weapons with specificity to the point where they wouldn't produce much fallout. And, we know both Phasers and torpedoes can be used as precision tools. In fact, most of the times when these weapons were used, they had to be calibrated very carefully to avoid potential fallout effects on a planetary surface and wipe out sentient life on it.

In the case of the Enterprise-D, it bore thousands of km deep hole in seconds using a very low (and tightly focused) phaser beam, which would have required gigaton yields in the first place - and other cases used even lower yields (which required weapons to be set to such levels in the first place to avoid catastrophic fallouts when used on planets, etc.).

So, while the weapons on-board Federation ships may not require large quantities of energy to run, through use of subspace technology they could exhibit orders of magnitude higher effects - depending on how they are calibrated.

As for yields being measured in 'isotonnes' in Trek, well, that could easily (again) be attributed to use of subspace technology. Plus, why assume that Starfleet would be using same measurements as we do right now? Its set centuries in the future, and it stands to reason that various measurements could undergo changes as well (however minor they may be).

I understand we are trying to put things into context based from our perspective, but I'm just saying that for whatever reason, Starfleet might have decided to use different measuring systems as a direct result of using Subspace technology and have changed terminologies as a result.

  • Per my comment earlier, the yields are specifically recorded in isotonnes, a measure that (purposefully) doesn't translate into real figures.
    – Valorum
    Commented Aug 3, 2019 at 21:19
  • Isotonnes are a simple indication that SF decided to use a different measuring system for technology that's radically different in comparison to what's used in the real world and what kinds of effects it has - aka, use of subspace technology in weaponry can easily augment destructive effects to very high degrees and have a plethora of different effects where using standard terminology would not be deemed enough of a description (for example, weapons in Trek were frequently used in non-military situations as scientific and precision tools to achieve different effects).
    – Deks
    Commented Aug 3, 2019 at 22:11

Mass x acceleration = force just a 247.5kg probe traveling at .99C Would generate around 32670MT of destructive force.

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    I'm not voting to delete because it is an answer, even though it is wrong in many different ways.
    – DavidW
    Commented May 5, 2019 at 4:39
  • That's not how they work
    – Valorum
    Commented May 5, 2019 at 7:31

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