What is the RDA file format?
An .rda file (also saved as .RData) is a binary serialization file produced by the R statistical computing environment using the save() function. It stores one or more named R objects - vectors, data frames, lists, statistical models, or entire workspaces - in R's native XDR (External Data Representation) binary format, which ensures cross-platform compatibility between Windows, Linux, and macOS.
Loading an .rda file with load() restores all saved objects directly into the current R environment under their original names. This differs from .rds files, which hold exactly one object and let the caller assign any name on load via readRDS(). For sharing a single object between scripts, .rds is generally preferred; .rda is more convenient for saving a complete workspace or a named collection of related objects.
By default, R compresses .rda files with gzip, though bzip2 and xz are also supported via the compress= argument to save(). The file header encodes the serialization format version: version 2 (R 1.4.0, December 2001) is the most widely compatible; version 3 (R 3.5.0, April 2018) adds support for long vectors and ALTREP objects but requires R 3.5.0 or later to read. R automatically offers to save the workspace as .RData on quitting.
Security & safety
RISK: MEDIUMRDA files can contain R code via serialized function/closure objects and environments. Loading an untrusted .rda file could execute code through serialized promise objects or active bindings. load() from unknown sources carries the same risk as running arbitrary R code. Only load .rda files from trusted sources.
Format details
in a nutshell- Oracle Storage Area file - Oracle uses .rda extension for some internal storage area descriptor files - entirely unrelated to R; extremely rare in practice.
Programs that open RDA files
Windows2 apps
RStudio (Posit)
Open-source In Environment pane click 'Import Dataset' or run load('file.rda') in the Console. Objects appear in the Environment pane.
R (base)
Open-source Run: load('path/to/file.rda') - objects are loaded into the current environment by name. 
macOS2 apps
RStudio (Posit)
Open-source Same as Windows: load() in Console or use Import Dataset in Environment pane. 
Linux2 apps
Technical details
deep spec| File type | Binary serialized R objects (one or more named objects per file) |
| MIME type | application/octet-stream |
| Magic bytes | 52 44 58 0A ("RDX\n") for binary XDR format; "RDX3\n" header for serialization version 3 |
| Encoding | XDR (External Data Representation) - big-endian, cross-platform binary standard |
| Byte order | Big-endian (mandated by XDR specification) |
| Compression | gzip by default; bzip2 and xz also supported via compress= argument to save() |
| Typical size | 1 KB - several GB (depends entirely on the objects saved) |
| Objects per file | Multiple named objects (unlike .rds which holds exactly one object per file) |
| Load behavior | load() restores all objects to the current R environment under their original names - can silently overwrite existing objects |
| Serialization version | v2 (R ≥ 1.4.0, December 2001); v3 (R ≥ 3.5.0, April 2018); version encoded in file header |
| Equivalent extension | .RData - identical binary format, different naming convention; R saves workspace as .RData on quit |
| OS support | Windows, Linux, macOS (fully cross-platform via XDR encoding) |
| Related format | .rds - single-object serialization via saveRDS()/readRDS(); preferred when sharing individual R objects |
| Released | 2001 (R serialization format version 2, introduced in R 1.4.0, December 2001) |
| Latest version | Serialization format version 3 (R 3.5.0, April 2018) - adds support for long vectors and ALTREP objects |
| Specification | cran.r-project.org |
RDA conversions
Community Q&A
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