NR - the Noise Rating Curve

Determine acceptable indoor environment noise levels for hearing preservation, speech communication and annoyance using Noise Rating curves. Compare measured sound pressure levels at different frequencies to find the appropriate NR rating.

Noise Rating Calculator

Enter the sound pressure levels (in dB) measured at different octave band frequencies to determine the Noise Rating - NR. The NR is determined by finding the highest ratio between measured values and the NR curve values.

Recommended NR Levels:

NR 25: Concert halls, broadcasting studios, churches
NR 30: Private dwellings, hospitals, theaters, cinemas, conference rooms
NR 35: Libraries, museums, schools, hospitals, executive offices
NR 40: Offices, restaurants, shops
NR 45: Department stores, supermarkets, general offices
NR 50: Typing pools, offices with machines
NR 60: Light engineering works
NR 70: Foundries, heavy engineering works

Calculator

Inputs

Sound Pressure Level at 31.5 Hz (dB)

Sound Pressure Level at 62.5 Hz (dB)

Sound Pressure Level at 125 Hz (dB)

Sound Pressure Level at 250 Hz (dB)

Sound Pressure Level at 500 Hz (dB)

Sound Pressure Level at 1000 Hz (dB)

Sound Pressure Level at 2000 Hz (dB)

Sound Pressure Level at 4000 Hz (dB)

Sound Pressure Level at 8000 Hz (dB)

Results

Ratio at 31.5 Hz (NR 70)--

Ratio at 62.5 Hz (NR 70)--

Ratio at 125 Hz (NR 70)--

Ratio at 250 Hz (NR 70)--

Ratio at 500 Hz (NR 70)--

Ratio at 1000 Hz (NR 70)--

Ratio at 2000 Hz (NR 70)--

Ratio at 4000 Hz (NR 70)--

Ratio at 8000 Hz (NR 70)--

Estimated Noise Rating - NR--

Noise Rating Curve	31.5 Hz	62.5 Hz	125 Hz	250 Hz	500 Hz	1000 Hz	2000 Hz	4000 Hz	8000 Hz
NR 0	55	36	22	12	5	0	-4	-6	-8
NR 10	62	43	31	21	15	10	7	4	2
NR 20	69	51	39	31	24	20	17	14	13
NR 30	76	59	48	40	34	30	27	25	23
NR 40	83	67	57	49	44	40	37	35	33
NR 50	89	75	66	59	54	50	47	45	44
NR 60	96	83	74	68	63	60	57	55	54
NR 70	103	91	83	77	73	70	68	66	64
NR 80	110	99	92	86	83	80	78	76	74
NR 90	117	107	100	96	93	90	88	86	85
NR 100	124	115	109	105	102	100	98	96	95
NR 110	130	122	118	114	112	110	108	107	105
NR 120	137	130	126	124	122	120	118	117	116
NR 130	144	138	135	133	131	130	128	127	126

NR - the Noise Rating Curve | MEPKit Engineering Tools | MEPKit