diff --git a/docs/usage.md b/docs/usage.md
index e31a7862..927bc28c 100644
--- a/docs/usage.md
+++ b/docs/usage.md
@@ -92,7 +92,7 @@ genome: 'GRCh37'
 
 You can also generate such `YAML`/`JSON` files via [nf-core/launch](https://nf-co.re/launch).
 
-Optionally, the `sample_size` parameter allows you to subset a random number of reads to be analysed. Note that it refers to an absolute number.
+Optionally, the `sample_size` parameter allows you to subset a random number of reads to be analysed. Both absolute numbers (e.g 10000) and relative numbers (e.g 0.25) can be specified.
 
 ```bash
 nextflow run nf-core/seqinspector --input ./samplesheet.csv --outdir ./results --sample_size 1000000 -profile docker
diff --git a/nextflow_schema.json b/nextflow_schema.json
index 5d663de7..c725f868 100644
--- a/nextflow_schema.json
+++ b/nextflow_schema.json
@@ -24,9 +24,9 @@
                     "fa_icon": "fas fa-file-csv"
                 },
                 "sample_size": {
-                    "type": "integer",
+                    "type": "number",
                     "description": "Take this number of reads as a subset.",
-                    "help_text": "Choose the size of the subset or 0, if no subsampling shall be performed. Note that it refers to an absolute number.",
+                    "help_text": "Choose the size of the subset or 0, if no subsampling shall be performed. Both absolute numbers (e.g 10000) and relative numbers (e.g 0.25) can be specified.",
                     "default": 0
                 },
                 "outdir": {