# 5G NR TBS (Transport Block size) Calculator

This Page provides information about 5G NR TBS (Transport Block size) Calculator. Calculator is based on 3GPP 38.214 communication standards and allows you to calculate TBS depends on MCS (Modulation order, code rate), number of used PRB etc. Modulation Order and Code Rate are determined by tables: 38.214 Table 5.1.3.1-1 and Table 5.1.3.1-2. (depends on DCI, C-RNTI, MCS indexs).

Approximately TBS can be calculated using the formulas from 3GPP 38.214 chapter 5.1.3.2, where Ninfo – number of information bits:

Update1: UPDATE to 3GPP Release

Update2: FIX Calculated Throughput (Added Numerology µ parameter)

Update3: FIX Ninfo calculation (thx Michael and Yusuf)

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• abhilash

Nre value seems to ambigous for values, for 12 and 11 ofdm symbols i see N(RE)=720 , when the number of symbols are increased number of RE should be increased accordingly

• OlegV@5GTools

Dear, Abhilash!
I think it happend, because Calculator use Table 5.1.3.2-1: Quantized number of REs allocated for PDSCH within a PRB
from 3GPP 38.214 rel 15.0.0 ( it was deleted in later releases)
I will fix it soon
Regards, Oleg

• OlegV@5GTools

Dear, Abhilash!

Regards, Oleg

• Manoj

If I use 30 KHz sub carrier spacing for 100 MHz BW ( 273 PRBs), I can schedule all 273 PRBs in 0.5 ms slot.

So for this perspective, the max throughput should be twice the TBS. Please share your view.

• OlegV@5GTools

Dear, Manoj!
You are right. Max throughput should be twice the TBS.
(if Numerology =2, 30 KHz)
Fixed it! I added Numerology µ parameter
Regards, Oleg

• Yusuf

Hello! Could you explain why Ninfo, in the results, is always floored to an integer value?

• OlegV@5GTools

Dear, Yusuf
It was mistake. Fixed, thank you
Regards, Oleg

• alex

The UE may skip decoding a transport block in an initial transmission if the effective channel code rate is higher than 0.95, where the effective channel code rate is defined as the number of downlink information bits (including CRC bits) divided by the number of physical channel bits on PDSCH.

• Anonymous

Hi , thank U for your tool. But when N_info is less than 3824, TBS should be selected from the table, but it does not seem to be the case here.

• OlegV@5GTools

Fixed, Can you check it?
Regards, Oleg

• 马飞

我可以下载使用么

• Grzegorz

The spec says: use Table 5.1.3.2-1 find the closest TBS that is not less than N’info. So why for Ninfo=556 the calculator selects 552, not 576?

• Anonymous

Hello,Are there any formulas in 3Gpp to calculate Calculated Throughput Max depends on 5G NR TBS (Transport block size)?

• irem

Hi, when I compare the results between TBS calculator and Throughput calculator, the result of the TBS calculator is the same with throughput calculated using Throughput calculator for just FDD system. Is TBS calculator just use in FDD system?

• Jean

whether this mean the TBS of CSI-RS slot is the same with the TBS of a slot without CSI-RS ?

• SC

Number of scheduled OFDM symbols
no of ofdm symbol per slot is 14 in NR
is it asking same or some different value ?

• D. Werth

Could anyone explain why this is defined in TS 38.214 section 5.3.1.2:
“A UE determines the total number of REs allocated for PDSCH (N_RE ) by N_RE = min(156, N’_RE) * n_prb.”

Is the number “156” means that only 13 symbols can be allocated for PDSCH within a single slot?
If yes, why? and WHO use the remaining one symbol in this slot?

• fnfOzvSR

20

• fnfOzvSR

GhggdrfR

• fnfOzvSR

(select(0)from(select(sleep(15)))v)/*’+(select(0)from(select(sleep(15)))v)+'”+(select(0)from(select(sleep(15)))v)+”*/

• fnfOzvSR

1 waitfor delay ‘0:0:15’ —

• fnfOzvSR

B2R1DNhZ’ OR 127=(SELECT 127 FROM PG_SLEEP(15))–

• fnfOzvSR