Top Physics subreddits

Largest Physics subreddits

Largest Physics subreddits

#	Subreddit	Members	12-mo growth	Commenters / mo
1	r/askscience	26.38M	+0.8%	3,145
2	P r/Physics	3.25M	+2.5%	3,801
3	A r/AskPhysics	1.57M	+4.7%	5,649
4	r/physicsmemes	365,875	+11%	1,818
5	P r/physicsgifs	224,994	+3.3%	42
6	r/PhysicsStudents	148,506	+23%	1,415
7	r/holofractal	121,461	+12%	276
8	r/quantum	92,734	+27%	224
9	r/Radiation	79,233	+36%	677
10	r/QuantumPhysics	71,907	+13%	162
11	r/TheoreticalPhysics	66,950	+48%	397
12	r/NuclearPower	65,492	+26%	642
13	r/CERN	57,349	+12%	180
14	P r/ParticlePhysics	41,418	+9.1%	47
15	O r/Optics	30,134	+28%	390
16	r/FluidMechanics	29,434	+40%	165
17	r/aerodynamics	26,708	+30%	234
18	r/HypotheticalPhysics	26,643	+39%	265
19	P r/physicsjokes	25,919	+4.7%	10
20	r/learnphysics	22,805	–	174
21	B r/Biophysics	17,022	–	55
22	Q r/quantummechanics	16,143	–	22
23	G r/geophysics	12,409	–	93
24	A r/apphysics	11,995	–	173
25	M r/Magnets	11,641	–	128

Fastest growing Physics subreddits

Member growth over 12 months, among subreddits that had at least 18,251 members a year ago.

Fastest growing Physics subreddits

#	Subreddit	12-mo growth	Members gained	Members	Commenters / mo
1	r/TheoreticalPhysics	+48%	+21,576	66,950	397
2	r/FluidMechanics	+40%	+8,440	29,434	165
3	r/HypotheticalPhysics	+39%	+7,486	26,643	265
4	r/Radiation	+36%	+21,157	79,233	677
5	r/aerodynamics	+30%	+6,088	26,708	234
6	O r/Optics	+28%	+6,570	30,134	390
7	r/quantum	+27%	+19,945	92,734	224
8	r/NuclearPower	+26%	+13,619	65,492	642
9	r/PhysicsStudents	+23%	+28,039	148,506	1,415
10	r/QuantumPhysics	+13%	+8,376	71,907	162
11	r/holofractal	+12%	+12,890	121,461	276
12	r/CERN	+12%	+5,987	57,349	180
13	r/physicsmemes	+11%	+36,124	365,875	1,818
14	P r/ParticlePhysics	+9.1%	+3,453	41,418	47
15	P r/physicsjokes	+4.7%	+1,163	25,919	10
16	A r/AskPhysics	+4.7%	+70,306	1.57M	5,649
17	P r/physicsgifs	+3.3%	+7,215	224,994	42
18	P r/Physics	+2.5%	+80,872	3.25M	3,801
19	r/askscience	+0.8%	+209,544	26.38M	3,145

Most members gained

Physics subreddits that gained the most members

#	Subreddit	Members gained	12-mo growth	Members	Commenters / mo
1	r/askscience	+209,544	+0.8%	26.38M	3,145
2	P r/Physics	+80,872	+2.5%	3.25M	3,801
3	A r/AskPhysics	+70,306	+4.7%	1.57M	5,649
4	r/physicsmemes	+36,124	+11%	365,875	1,818
5	r/PhysicsStudents	+28,039	+23%	148,506	1,415
6	r/TheoreticalPhysics	+21,576	+48%	66,950	397
7	r/Radiation	+21,157	+36%	79,233	677
8	r/quantum	+19,945	+27%	92,734	224
9	r/NuclearPower	+13,619	+26%	65,492	642
10	r/holofractal	+12,890	+12%	121,461	276
11	r/FluidMechanics	+8,440	+40%	29,434	165
12	r/QuantumPhysics	+8,376	+13%	71,907	162
13	r/HypotheticalPhysics	+7,486	+39%	26,643	265
14	P r/physicsgifs	+7,215	+3.3%	224,994	42
15	O r/Optics	+6,570	+28%	30,134	390
16	r/aerodynamics	+6,088	+30%	26,708	234
17	r/CERN	+5,987	+12%	57,349	180
18	P r/ParticlePhysics	+3,453	+9.1%	41,418	47
19	P r/physicsjokes	+1,163	+4.7%	25,919	10

Most active Physics subreddits

People who comment in a month, the average of the three months ending September 2026.

Most active Physics subreddits

#	Subreddit	Commenters / mo	Posts / mo	Members
1	A r/AskPhysics	5,649	1,388	1.57M
2	P r/Physics	3,801	674	3.25M
3	r/askscience	3,145	5,740	26.38M
4	r/physicsmemes	1,818	197	365,875
5	r/PhysicsStudents	1,415	533	148,506
6	r/Radiation	677	139	79,233
7	r/NuclearPower	642	172	65,492
8	r/TheoreticalPhysics	397	116	66,950
9	O r/Optics	390	146	30,134
10	r/holofractal	276	42	121,461
11	r/HypotheticalPhysics	265	425	26,643
12	r/aerodynamics	234	54	26,708
13	r/quantum	224	118	92,734
14	r/CERN	180	96	57,349
15	r/learnphysics	174	106	22,805
16	A r/apphysics	173	84	11,995
17	r/FluidMechanics	165	78	29,434
18	r/QuantumPhysics	162	81	71,907
19	M r/Magnets	128	56	11,641
20	G r/geophysics	93	38	12,409
21	A r/AP_Physics	59	76	4,642
22	r/seancarroll	57	8	7,327
23	B r/Biophysics	55	21	17,022
24	P r/ParticlePhysics	47	27	41,418
25	T r/Teslacoil	45	24	6,594

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• All topics

How these lists are made

• Members are the member counts measured in October 2026.
• Activity (commenters and posts per month) is the average of the three months ending September 2026. Posts by known bots are not counted.
• 12-month growth compares members now with members a year earlier. A subreddit is ranked by growth only if it already had at least 18,251 members a year ago (the median for subreddits with a known growth), so brand-new communities don't top the list from a base of zero. Subreddits with more monthly active users than 0.808 per member, a sign of inflated activity, are left out of the growth and activity lists.
• NSFW communities are excluded: those Reddit marks as 18+, those where most posts are NSFW, and the Adult Content topic.
• Topics follow Reddit's own community categories.
• The lists are rebuilt every month. Each list shows the top 25 (100 for the largest subreddits overall). Download all lists as CSV (free to reuse under CC BY 4.0, with a link to this page).