| Document And Entity Information | Dec. 09, 2021 |
| Document Information Line Items | |
| Entity Registrant Name | Frequency Electronics, Inc. |
| Trading Symbol | FEIM |
| Document Type | 8-K |
| Amendment Flag | false |
| Entity Central Index Key | 0000039020 |
| Document Period End Date | Dec. 9, 2021 |
| Entity Emerging Growth Company | false |
| Entity Incorporation, State or Country Code | DE |
| Entity File Number | 1-8061 |
| Entity Tax Identification Number | 11-1986657 |
| Entity Address, Address Line One | 55 Charles Lindbergh Blvd. |
| Entity Address, City or Town | Mitchel Field |
| Entity Address, State or Province | NY |
| Entity Address, Postal Zip Code | 11553 |
| City Area Code | (516) |
| Local Phone Number | 794-4500 |
| Written Communications | false |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Title of 12(b) Security | Common Stock (par value $1.00 per share) |
| Security Exchange Name | NASDAQ |
