What is 5G NR numerology (μ)?

Numerology is the index μ that scales the subcarrier spacing as 15 × 2^μ kHz. So μ = 0 is 15 kHz, μ = 1 is 30 kHz, up to μ = 4 at 240 kHz. Wider spacing shortens the symbol and slot, which cuts latency and helps at high carrier frequencies where phase noise matters.

What is the slot length at 30 kHz SCS?

Slot duration is 1 ms / 2^μ, so at 30 kHz (μ = 1) a slot is 0.5 ms. A normal cyclic prefix always carries 14 OFDM symbols per slot regardless of numerology, so the higher spacing simply packs those 14 symbols into less time.

How many slots fit in a subframe for each numerology?

The 1 ms subframe holds 2^μ slots: 1 slot at 15 kHz, 2 at 30 kHz, 4 at 60 kHz, 8 at 120 kHz and 16 at 240 kHz. The radio frame stays 10 ms with 10 subframes; only the slot count inside it grows with μ.

Which numerologies are allowed for data versus SSB?

60 kHz can use either a normal or extended CP; the others are normal CP only. 240 kHz (μ = 4) is reserved for the SSB in FR2 and is not used for data channels, while PDSCH/PUSCH in FR1 typically run at 15 or 30 kHz and FR2 data uses 60 or 120 kHz.

5G NR Numerology Planner

Pick a numerology (μ) or a subcarrier spacing and see the full frame structure — symbol duration, slot duration, slots per frame, CP length and maximum PRB count — as defined by 3GPP TS 38.211 and TS 38.101.

Numerology (μ) / SCS

Channel BW (MHz, optional)

Used to estimate PRB count.

SCS

30 kHz

Slot duration

0.5 ms

Symbol duration

35.68 μs

Slots / frame

Slots / subframe

CP type

Normal (NCP)

Max PRBs

275

PRBs at BW

~250

SCS 30 kHz enables a slot-based latency of 0.5 ms. Mini-slot scheduling (2, 4 or 7 symbols) brings it down further for URLLC.

Slot duration comparison

μ=0 · 15kHz

1 ms

μ=1 · 30kHz

0.5 ms

μ=2 · 60kHz

0.25 ms

μ=3 · 120kHz

0.125 ms

μ=4 · 240kHz

0.0625 ms

All numerologies at a glance

μ	SCS	Slot (ms)	Symbol (μs)	Slots/frame	CP	Typical use
0	15 kHz	1	71.35	10	Normal (NCP)	LTE-like, legacy, low-band FR1 (600–900 MHz)
1	30 kHz	0.5	35.68	20	Normal (NCP)	Typical FR1 mid-band (n77 / n78 / n41 at 3.5 GHz)
2	60 kHz	0.25	17.84	40	Normal or Extended (ECP)	Optional FR1 / FR2 data channels, URLLC
3	120 kHz	0.125	8.92	80	Normal (NCP)	FR2 mmWave data (n257, n258, n260, n261)
4	240 kHz	0.0625	4.46	160	Normal (NCP)	FR2 SSB only (synchronisation signal block)

About 5G numerology

5G NR introduced the concept of numerology — indexed by μ ∈ {0, 1, 2, 3, 4} — to allow a single air-interface design to cover everything from 600 MHz low-band rural coverage to 40 GHz mmWave deployments. The subcarrier spacing is SCS = 15 × 2^μ kHz and the slot duration is 1 / 2^μ ms, so every time you double μ the slot halves and you double the number of slots per 10 ms radio frame.

μ=0 (15 kHz) gives you LTE-like timing and is used for FR1 low bands. μ=1 (30 kHz) is the workhorse for mid-band deployments on n77, n78 and n41. μ=2 (60 kHz) is an option for URLLC in FR1 and also appears in FR2. μ=3 (120 kHz) is the default data numerology for FR2 mmWave, and μ=4 (240 kHz) is reserved for the SSB (Synchronization Signal Block) in FR2 where symbols must be short enough to ride through beam-sweeping.

Who uses this planner?

Radio designers use it to decide the right SCS per deployment. Capacity planners use the PRB count at a given channel bandwidth to size throughput. URLLC use-case architects use the slot duration to estimate user-plane latency budgets. Anyone studying for 5G-related certifications (3GPP, TELCOMA, TCCA) needs this table memorised.

Related tools

How to use the 5G Numerology Planner

Select a numerology. Choose μ from 0 to 4 (or pick the subcarrier spacing directly).
Read the SCS and symbol timing. The tool shows the 15 × 2^μ kHz spacing and the resulting OFDM symbol duration.
Check the slot structure. See the slot length (1 ms / 2^μ) and that 14 symbols sit in each normal-CP slot.
Compare across numerologies. Step through several μ values to weigh latency against the slots-per-subframe count for your deployment.

Frequently asked questions

What is 5G NR numerology (μ)?: Numerology is the index μ that scales the subcarrier spacing as 15 × 2^μ kHz. So μ = 0 is 15 kHz, μ = 1 is 30 kHz, up to μ = 4 at 240 kHz. Wider spacing shortens the symbol and slot, which cuts latency and helps at high carrier frequencies where phase noise matters.
What is the slot length at 30 kHz SCS?: Slot duration is 1 ms / 2^μ, so at 30 kHz (μ = 1) a slot is 0.5 ms. A normal cyclic prefix always carries 14 OFDM symbols per slot regardless of numerology, so the higher spacing simply packs those 14 symbols into less time.
How many slots fit in a subframe for each numerology?: The 1 ms subframe holds 2^μ slots: 1 slot at 15 kHz, 2 at 30 kHz, 4 at 60 kHz, 8 at 120 kHz and 16 at 240 kHz. The radio frame stays 10 ms with 10 subframes; only the slot count inside it grows with μ.
Which numerologies are allowed for data versus SSB?: 60 kHz can use either a normal or extended CP; the others are normal CP only. 240 kHz (μ = 4) is reserved for the SSB in FR2 and is not used for data channels, while PDSCH/PUSCH in FR1 typically run at 15 or 30 kHz and FR2 data uses 60 or 120 kHz.

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