Weir & Orifice Calculator

The Weir and Orifice Calculator is used to determine the inlet capacity in sag (ponding) conditions by use of the Weir and Orifice equations. Knowing this information will allow you to select the proper grate type and size for your specific job or project.

Instructions:

1. Select a catalog number (will automatically fill in Open Area and Perimeter) or enter your own values
2. Enter head value
3. Click "calculate"

The results will determine automatically if your situation falls into a Weir, Transitional or Orifice flow. Additionally, Neenah grates which fall within the parameters chosen will appear below the calculator.

Catalog Number and Grate Type:
Select Number and Grate R-1792-AG: G R-1792-BG: G R-1792-CG: G R-1792-DG: G R-1792-EG: G R-1792-FG: G R-1792-GG: G R-1792-HG: G R-1792-JG: G R-1792-KG: G R-1878-A10G: A or C R-1878-A1G: A or C R-1878-A2G: A or C R-1878-A3G: A or C R-1878-A4G: A or C R-1878-A5G: A or C R-1878-A6: Q R-1878-A6G: A or C R-1878-A7G: A or C R-1878-A8G: A or C R-1878-A9G: A or C R-1878-B10G: C R-1878-B11G: A R-1878-B1G: A R-1878-B2G: A R-1878-B3G: A R-1878-B4G: A R-1878-B5G: A R-1878-B6G: C R-1878-B7G: A R-1878-B8G: A R-1878-B9G: C R-1879-A10G: A or C R-1879-A1G: A or C R-1879-A2G: A or C R-1879-A3G: A or C R-1879-A4G: A or C R-1879-A5G: A or C R-1879-A6G: A or C R-1879-A7G: A or C R-1879-A8G: A or C R-1879-A9G: A or C R-1879-B10G: C R-1879-B1G: A R-1879-B2G: C R-1879-B3G: C R-1879-B4G: A R-1879-B5G: A R-1879-B6G: A R-1879-B7G: A R-1879-B8G: A R-1879-B9G: A R-1881-A: Q R-1881-B: Q R-1881-C: Q R-1881-D: P R-1881-E: P R-1881-F: P R-1881-G: P R-1881-H: P R-1881-J: P R-1881-K: P R-1881-L: P R-1881-M: Q R-1881-N: Q R-2014: C R-2014: E R-2015: D R-2015: C R-2015: G R-2030: D R-2030: C R-2031: D R-2031: E R-2040: D R-2040: C R-2040: E R-2040: F R-2050: D R-2050: C R-2050: E R-2050: F R-2060: A R-2060: B R-2060: C R-2060: E R-2070: D R-2070: B R-2070: E R-2077: B R-2077: C R-2077: D R-2077: E R-2077: F R-2080: D R-2080: C R-2090: A R-2090: B R-2090: C R-2090: D R-2090: E R-2090: G R-2100: A R-2100: C R-2100: E R-2100: F R-2110: A R-2110: E R-2112: A R-2112: B R-2112: C R-2112: E R-2112: F R-2112: G R-2120: A R-2120: C R-2120: F R-2120: G R-2250: G R-2251: G R-2255: C R-2255: G R-2270: G R-2275: G R-2290: K R-2290-A: K R-2290-B: K R-2293: G R-2296: B R-2296: F R-2297: B R-2297: F R-2298: B R-2298: F R-2299: B R-2299: F R-2300: G R-2300: C R-2370: B R-2370: F R-2370: A R-2370: G R-2371: G R-2390: G R-2390: C R-2392: C R-2392: G R-2394: G R-2395-1: G R-2398: G R-2401: G R-2401: C R-2401-A: G R-2401-B: E R-2402: G R-2402: C R-2404: G R-2405: A R-2405: C R-2410: K R-2411-A: G R-2412-A: G R-2412-A1: E R-2412-A2: G R-2412-A3: C R-2412-A3: E R-2412-A4: C R-2412-A5: K R-2412-A6: G R-2414: D R-2418: G R-2418-A: K R-2420-A: A R-2420-B: G R-2421-A: A R-2422-A: K R-2422-C: G R-2423: G R-2424-A: G R-2427: D R-2427-A: G R-2428: D R-2428: C R-2428: F R-2429: D R-2429: E R-2429: G R-2435: G R-2437: D R-2437: E R-2437-B: G R-2438: D R-2438: E R-2453: K R-2461-A: A R-2461-A: B R-2461-A: C R-2464: D R-2466-A: B R-2466-A: E R-2467: C R-2467: D R-2471: D R-2471-B: D R-2474: A R-2474: G R-2475: A R-2481: A R-2494: G R-2496: G R-2498: G R-2498-A: G R-2498-B: G R-2499: G R-2500: G R-2501: G R-2501: C R-2502: D R-2502: G R-2504: G R-2504: D R-2510: C R-2510-1: G R-2510-2: G R-2510-A: C R-2525-A: E R-2525-C: G R-2525-D: G R-2525-E: E R-2525-F: G R-2525-G: G R-2533: A R-2534: C R-2535: C R-2535-A: C R-2540: D R-2540-A: D R-2545: K R-2546: K R-2548: V R-2549: D R-2552: K R-2552-A: K R-2552-B: K R-2553: G R-2554: G R-2555: G R-2556: G R-2556-A: F R-2557: G R-2558: G R-2559: F R-2560-A: Beehive R-2560-B: Beehive R-2560-C: Beehive R-2560-C1: Beehive R-2560-C2: Beehive R-2560-D: Beehive R-2560-D1: Beehive R-2560-D2: Beehive R-2560-D3: Beehive R-2560-D5: Beehive R-2560-D6: Beehive R-2560-D7: Beehive R-2560-D8: Beehive R-2560-E: Beehive R-2560-E1: Beehive R-2560-E10: Beehive R-2560-E2: Beehive R-2560-E5: Beehive R-2560-E6: Beehive R-2560-E7: Beehive R-2560-E8: Beehive R-2560-E9: Beehive R-2560-EA: Beehive R-2560-EB: Beehive R-2560-G: Beehive R-2561: Beehive R-2561-A: Beehive R-2563: Beehive R-2564: Beehive R-2565-A: G R-2565-C: G R-2565-E: G R-2565-F: G R-2565-G: G R-2565-H: G R-2565-J: G R-2569: A R-2570: G R-2571-A: F R-2571-B: F R-2571-C: F R-2571-D: F R-2571-D1: F R-2571-D2: F R-2571-D3: F R-2571-D4: F R-2571-E: F R-2572: F R-2573: F R-2574: B R-2577: B R-2578: C R-2579: B R-2580-A: G R-2580-A1: C R-2580-C: G R-2586-A: E R-2586-B: G R-2586-C: E R-2586-D: G R-2586-E: G R-2586-F: G R-2586-G: G R-2586-H: E R-2586-K: G R-2586-M: G R-2586-N: G R-2586-O: G R-2588-A: G R-2588-B: G R-2588-C: G R-2595-A: D R-2600: K R-2650: G R-2668: C R-2680: G R-2682: A R-2750: Q R-3010: S R-3010: A R-3010: L R-3010: Diagonal R-3010: D R-3015: L R-3015: Diagonal R-3030: A R-3030: D R-3030: Diagonal R-3030: L R-3031-B: S R-3032-B: S R-3033-B: S R-3034-B: S R-3035-A: S R-3036-B: S R-3037-A: S R-3038-A: S R-3039-A: S R-3065: Diagonal R-3065-L: L R-3065-V: V R-3066: Diagonal R-3067: Diagonal R-3067-C: C R-3067-L: L R-3067-V: V R-3070: A R-3070: D R-3070: L R-3070: Diagonal R-3070: V R-3075: Diagonal R-3075-L: L R-3075-V: V R-3076: V R-3077: V R-3077-L: V R-3077-R: V R-3078: V R-3079: L R-3157-1: A R-3157-2: V R-3157-A: K R-3159-A: S R-3161: S R-3165: A R-3169: B R-3170: B R-3203-A: A or C R-3203-B: A or C R-3203-C: A or C R-3205: K R-3210-A: C R-3210-L: L R-3210-Q: Q R-3220: C R-3220-L: L R-3222-1A: L R-3222-C: C R-3222-LA: L R-3227: D R-3227-C: C R-3227-D: Diagonal R-3228-BD: Diagonal R-3228-G: D R-3228-H: C R-3228-J: D R-3228-K: C R-3229-A: C R-3229-L: L R-3233: A R-3233-D: A R-3234-B1: C R-3235: C R-3236: C R-3236-1: C R-3236-A: C R-3236-B: C R-3237: C R-3237-1: C R-3237-A: C R-3237-B: C R-3238: C R-3246: C R-3246-A: C R-3246-A: Diagonal R-3246-AL: L R-3246-CC: C R-3246-CL: L R-3246-E: C R-3246-F: C R-3247-2D: Diagonal R-3249-F: S R-3250-1: K R-3250-A: K R-3250-B: K R-3250-BL: L R-3250-BSP: V R-3250-BV: V R-3250-C: K R-3250-CL: L R-3250-CV: V R-3250-DV: V R-3251: C R-3252-A: V R-3260-A: A R-3261-A1: C R-3266: V R-3270: A R-3273-A: C R-3274: C R-3274-A: C R-3274-B: C R-3275: A R-3278-A: C R-3278-AL: L R-3280-A: C R-3280-B: C R-3281-A: C R-3281-AL: L R-3286-8V: V R-3287-10V: V R-3287-15: V R-3287-5: V R-3287-SB10: S R-3288-E2: Diagonal R-3288-HV2: V R-3288-HV2: L R-3289-C: L R-3289-C: Diagonal R-3289-HV: V R-3289-HV R-3290: C R-3290-A: C R-3290-B: D R-3290-C: D R-3291: C R-3292: C R-3295: L R-3295-2: L R-3295-3: L R-3297-1: C R-3337-A: C R-3338-F: A R-3338-G: A R-3339: C R-3339-A: A or C R-3340-B: C R-3340-D: C R-3341: K R-3342: K R-3344: K R-3345: K R-3346: K R-3347: K R-3347-A: K R-3348: K R-3349-A: K R-3350: K R-3351: K R-3356-A: K R-3357-A: K R-3359: K R-3360-A: K R-3361: K R-3362: C R-3362-1: C R-3362-L: L R-3363-1: C R-3381: K R-3382: K R-3393-A: K R-3396: K R-3397: A R-3397-1: V R-3401: D R-3401-B: B R-3401-C: B R-3402: A or C R-3402-E: A or C R-3403: A or C R-3403-A1: A R-3403-F: A R-3404: A or C R-3405: A or C R-3405-A: A or C R-3405-B: A or C R-3406: C R-3406-2: C R-3406-A: C R-3406-A2: C R-3408-AL: L R-3408-BL: L R-3408-L: L R-3409: C R-3413: C R-3415: A R-3416: A R-3420: A R-3423: B R-3425-A: K R-3425-B: K R-3429-A: A or C R-3430: A or C R-3433: A or C R-3437: C R-3438-A: A or C R-3448-B: C R-3448-C: C R-3448-D: S R-3449: C R-3451: C R-3451-B: C R-3454: A R-3454-B: D R-3454-BL: L R-3455-A: A R-3455-C: A R-3457-C2: B R-3460-A: A R-3460-D: C R-3461: C R-3462-B: Diagonal R-3463-B: Diagonal R-3465: A R-3466-A: A R-3469: A R-3469-E2: B or D R-3470: L R-3470-2: L R-3471: C R-3472: A or C R-3473: C R-3475: A R-3475-1: A R-3475-3: A R-3475-E: A R-3475-F: C R-3475-G: C R-3475-H: C R-3477-A: C R-3480: C R-3480-A: A R-3491-A: G R-3491-G: G R-3491-H: G R-3491-J: G R-3492-1: G R-3492-BG: G R-3492-CG: G R-3493-C: G R-3501-D2A: M R-3501-E2: M R-3501-H4: M R-3501-HL: M R-3501-L1A: M R-3501-M: M R-3501-N: M R-3501-P: M R-3501-R: M R-3501-TL: M R-3501-TR: M R-3502-A: M R-3502-B: M R-3502-D2: M R-3503-A: M R-3503-B: M R-3504-F: M R-3506-A2: M R-3506-B: M R-3507-C: M R-3507-D: M R-3508-A2: M R-3508-B: M R-3508-B1: M R-3508-B2: M R-3508-C: M R-3509: M R-3510: M R-3511: M R-3513: M R-3514-F: M R-3514-F2: M R-3516: M R-3516-1: M R-3517: M R-3526-1: K R-3527-G R-3527-M: V R-3527-V: V R-3528-V: V R-3529-V: V R-3531-A: A or C R-3531-B: A or C R-3531-C: A or C R-3531-D: A or C R-3531-E: A or C R-3540: L R-3540-2: L R-3541: L R-3541-2: L R-3550-2: L R-3560: A or C R-3561: A or C R-3562: C R-3570: A R-3570-A: A R-3571: A R-3571-A: A R-3572-2D: Diagonal R-3572-2L: L R-3572-A: Diagonal R-3573-2D: Diagonal R-3573-2L: L R-3573-2Q: Q R-3574-2D: Diagonal R-3574-2L: L R-3574-2Q: Q R-3575: B R-3576: Diagonal R-3577: D R-3578: L R-3580: L R-3580-1: L R-3581: V R-3588: D R-3588-A: A R-3588-LL: L R-3588-LL4: L R-3588-LR: L R-3588-LR4: L R-3589: D R-3589-A: A R-3589-LL: L R-3589-LL4: L R-3589-LR: L R-3589-LR4: L R-3591: A R-3593: C R-3599-A: L R-3807: K R-3808-1: C R-3808-2: C R-3900-B: L R-3900-C: L R-3900-D: L R-3919: Diagonal R-3920-V: V R-3921-V: V R-3922: V R-3922-A: V R-3924: B R-3928: B R-3930: B or D R-3931: B or D R-3935: A or C R-3936-A: C R-3940: A R-3942: V R-3943: V R-3945: L R-3948-A: C R-3948-V: V R-3951: L R-3952: D R-3954: B R-3961: D R-3976: B R-3977: B R-4001-B: C R-4003-A: A R-4003-B: A R-4003-C: A R-4004-A: C R-4004-B: B R-4004-C: B R-4004-G1: D R-4005-A2: B or D R-4006: B or D R-4007: B or D R-4007-A6: B or D R-4008-B: B or D R-4014-B1: C R-4014-C1: C R-4014-T: D R-4014-T1: D R-4014-TL: L R-4015-A: B R-4015-A1: B R-4015-B: C R-4015-C: B R-4015-D: B R-4016-B: C R-4016-H1: A R-4016-K: D R-4018: B R-4030-10: G R-4030-12: G R-4030-15: G R-4030-18: B R-4030-21: B R-4030-24: B R-4030-27: G R-4030-30: G R-4030-4: G R-4030-6: G R-4030-8: G R-4040-10: E R-4040-12: E R-4040-15: E R-4040-18: E R-4040-21: G R-4040-24: G R-4040-27: G R-4040-30: G R-4040-6: E R-4040-8: E R-4215-A: Beehive R-4215-C: Beehive R-4216-B: Beehive R-4216-D: Beehive R-4340-A: Beehive R-4340-B: Beehive R-4340-C: Beehive R-4340-F: Beehive R-4340-F1: Beehive R-4340-G: Beehive R-4340-H: Beehive R-4341-A: Beehive R-4342: Beehive R-4343: Beehive R-4344: Beehive R-4345: Beehive R-4346: Beehive R-4349-A: Beehive R-4349-B: Beehive R-4349-C: Beehive R-4349-D: Beehive R-4350-1: Beehive R-4350-A: Beehive R-4350-B: Beehive R-4350-C: Beehive R-4350-D: Beehive R-4350-E: Beehive R-4351-B: Beehive R-4351-D: Beehive R-4351-E: Beehive R-4352: Beehive R-4353: Beehive R-4360-A: Beehive R-4360-B: Beehive R-4360-C: Beehive R-4360-D: Beehive R-4370-1: C R-4370-10: G R-4370-12: F R-4370-13: G R-4370-15: D R-4370-17: D R-4370-18: E R-4370-2: G R-4370-21: D R-4370-22: D R-4370-23: G R-4370-25: G R-4370-26: G R-4370-27A: G R-4370-3: E R-4370-4: G R-4370-5: G R-4370-6: G R-4370-7: G R-4370-8: E R-4370-9: C R-4373-10: K R-4373-12: K R-4373-15: K R-4373-2: K R-4373-3: K R-4373-4: K R-4373-6: K R-4373-8: K R-4380-10: E R-4380-11: E R-4380-12: E R-4380-13: G R-4380-13A: E R-4380-14: E R-4380-15: E R-4380-16: E R-4380-17: E R-4380-18: G R-4380-21: G R-4380-22: G R-4380-23: G R-4380-24: G R-4380-25: G R-4380-26: G R-4380-4: E R-4380-4A: E R-4380-4A1: E R-4380-6: G R-4380-7: G R-4380-8: E R-4380-9: E R-4385-B: E R-4385-C: E R-4385-E: E R-4385-F: E R-4385-G: E R-4385-H: G R-4385-J: G R-4385-K: G R-4389-O: B R-4390: B R-4400: B R-4401: A R-4403: A R-4404-C: B R-4406: B R-4406-1: A R-4406-2: C R-4406-C: A R-4407-2A: B R-4408: B R-4409: A R-4409-A: C R-4409-C: B R-4409-E: A R-4409-G: B R-4410: B R-4421: C R-4423-A: A R-4424: A R-4430-A: A R-4430-B: C R-4435-1: C R-4441-1: Q R-4443: A R-4449: A R-4450: A R-4450-A: A R-4451: C R-4454: C R-4460: A R-4462: B R-4470: A R-4511: A R-4525: A R-4530: A R-4531: A R-4540: C R-4541: A R-4544: A R-4545: A R-4548: A R-4550: C R-4552: A R-4557: A R-4558: C R-4570-1: A R-4570-2: A R-4573: A R-4575-A: A R-4579: A R-4583: A R-4584: A R-4585: A R-4586: A R-4600: A R-4603-A: A R-4604: C R-4604-C: A R-4604-D: A R-4608: A R-4610: A R-4620: A R-4630: C R-4632: C R-4640: A R-4641-A: A R-4641-C: C R-4641-F: A R-4649: A R-4649-1: C R-4652: A R-4660: C R-4662: A R-4670-A: A R-4671: A R-4672: C R-4689: C R-4692-A: D R-4698: A R-4710: C R-4711: C R-4718: A R-4720: C R-4721-A: A R-4725: C R-4730: A R-4731: A R-4732: A R-4736: C R-4738: A R-4739: C R-4740: C R-4750: C R-4750-1: A R-4751: C R-4752: C R-4755-B: A R-4755-C: C R-4759: C R-4760: C R-4762: C R-4765: A R-4780: C R-4781: C R-4792: C R-4795: A R-4798: C R-4808-A: Q R-4810: C R-4820: C R-4821-A: C R-4825: C R-4825-A: A R-4825-B: C R-4826: A R-4828: A R-4829: C R-4832: C R-4832-B: C R-4833: A R-4837: A R-4839: A R-4840: C R-4843: A R-4850: C R-4852: C R-4852-A: Q R-4853: A R-4853-A: A R-4853-B1: C R-4855: A R-4856: C R-4857: A R-4859-C: A R-4871: B R-4880: C R-4880-C: C R-4882: A R-4882-A: A R-4884-A: C R-4890: C R-4891: A R-4893: C R-4893-B: C R-4894: C R-4895-2: A R-4938: A R-4938-1: A R-4938-B: A R-4939-B: K R-4941-A: B R-4942-A: A R-4943: K R-4943-A: K R-4943-B: K R-4976-1: A R-4976-1: B R-4976-2: A R-4976-2: B R-4976-3: A R-4976-3: B R-4976-4: A R-4976-4: B R-4976-5: B R-4977-1: A R-4977-1: B R-4977-2: A R-4977-2: B R-4977-3: A R-4977-3: B R-4977-4: A R-4977-4: B R-4977-5: A R-4977-5: B R-4990-AA: A R-4990-AX: A R-4990-AX: C R-4990-AX: P R-4990-BA: A R-4990-BX: A R-4990-BX: C R-4990-BX: P R-4990-CA: A R-4990-CX: A R-4990-CX: C R-4990-CX: P R-4990-CX: Q R-4990-DA: C R-4990-DA: A R-4990-DX: A R-4990-DX: P R-4990-DX: Q R-4990-DX: C R-4990-EA: A R-4990-EX: A R-4990-EX: C R-4990-EX: P R-4990-FA: A R-4990-FX: A R-4990-FX: C R-4990-FX: P R-4990-GX: C R-4990-GX: A R-4990-HA: A R-4990-HX: A R-4990-HX: C R-4990-JX: C R-4990-JX: A R-4990-KA2: A R-4990-KX: A R-4990-KX: C R-4990-LX: C R-4990-LX: A R-4990-MX: A R-4990-MX: C R-4990-NX: C R-4990-NX: A R-4990-OA: A R-4990-OX: A R-4993-AAB: A R-4993-BAB: A R-4993-CAB: A R-4993-DAB: A R-4993-DAB: C R-4993-EAB: A R-4993-FAB: A R-4993-HAB: A R-4993-KAB: A R-4993-OAB: A R-4994-AAB: A R-4994-BAB: A R-4994-CAB: A R-4994-DAB: A R-4994-DAB: C R-4994-EAB: A R-4994-FAB: A R-4994-HAB: A R-4994-KAB: A R-4994-OAB: A R-4995-A1: B R-4995-A1: C R-4995-A2: B R-4996-A: Q R-4996-A1: C R-4996-A1: Diagonal R-4996-A2: B R-4996-A3: C R-4996-B: Q R-4996-C: A R-4996-C: C R-4996-C: L R-4996-C: Q R-4996-C: P R-4999-AA: A R-4999-AX: A R-4999-AX: P R-4999-AX: C R-4999-BA: A R-4999-BX: A R-4999-BX: C R-4999-BX: P R-4999-CA: A R-4999-CX: A R-4999-CX: C R-4999-CX: P R-4999-CX: Q R-4999-DA: C R-4999-DA: A R-4999-DX: A R-4999-DX: C R-4999-DX: P R-4999-DX: Q R-4999-EA: A R-4999-EX: A R-4999-EX: C R-4999-EX: P R-4999-FA: A R-4999-FX: A R-4999-FX: C R-4999-FX: P R-4999-GX: C R-4999-GX: A R-4999-HA: A R-4999-HX: A R-4999-HX: C R-4999-JX: C R-4999-JX: A R-4999-KA2: A R-4999-KX: A R-4999-KX: C R-4999-L2: L R-4999-L3: L R-4999-L6: L R-4999-L7: L R-4999-L9: L R-4999-LX: A R-4999-LX: C R-4999-MX: C R-4999-MX: A R-4999-NX: A R-4999-NX: C R-4999-OA: A R-4999-OX: A R-5901-A: G R-5901-B: G R-5901-C: G R-5901-D: G R-5901-E: G R-5901-F: G R-5901-G: G R-5901-H: G R-5901-J: G R-5901-K: G R-6020: G R-6040: G R-6070: G R-6077: G R-6080: G R-6110: G R-6111: G R-6112: G R-6113: G R-6114: G R-6115: G R-6116: G R-6117: G R-6118: G R-6130: G R-6131: G R-6132: G R-6133: G R-6134: G R-6136: G R-6137: G R-6352-A: G R-6352-B: G R-6352-D: G R-6352-E: G R-6352-G: G R-6400-AO: G R-6400-BO: G R-6400-CO: G R-6400-DO: G R-6450-AG: G R-6450-BG: G R-6450-CG: G R-6450-DG: G R-6450-EG: G R-6450-FG: G R-6450-GG: G R-6450-HG: G R-6450-JG: G R-6450-KG: G R-6672-1: A or C R-6672-A: A or C R-6672-B: A or C R-6672-C: A or C R-6672-D: A or C R-6672-E: A or C R-6672-F: A or C R-6672-F: Q R-6672-G: A or C R-6672-H: A or C R-6672-J: A or C R-6672-K: A or C R-6672-M: A or C R-6672-Q: A or C R-6673-A: A R-6673-B: A R-6673-C: A R-6673-D: A R-6673-E: A R-6673-J: A R-6673-K: A R-6673-L: A R-6673-N: A R-6673-O: A R-6673-Q1: A R-7511: Beehive R-7516 R-7516-C R-7516-D
Lineal feet of trench:	Flow direction:
	Both Directions    One Direction
Feet perimeter (P):	Head in feet (h):	Free open area in sq. ft. (A):
Weir capacity in cfs:	Transitional flow in cfs:	Orifice capacity in cfs:

NOTE: The above results do not account for the dome height of Beehive-type grates. Please take note of this when determining the Head (h) value.

For additional information regarding Neenah Inlet Grate Capacities, please contact Joe Falle P.E., at (920)729.3653 or email at joseph.falle@neenahenterprises.com.