diff --git a/src/types/generate.rs b/src/types/generate.rs
index b2d9b1f..26de1a4 100644
--- a/src/types/generate.rs
+++ b/src/types/generate.rs
@@ -137,20 +137,20 @@ pub struct GenerateResponse {
     pub done_reason: Option<String>,
 
     /// Time spent generating the response in nanoseconds
-    pub total_duration: Option<usize>,
+    pub total_duration: Option<u64>,
 
     /// Time spent loading the model in nanoseconds
-    pub load_duration: Option<usize>,
+    pub load_duration: Option<u64>,
 
     /// Number of input tokens in the prompt
-    pub prompt_eval_count: Option<usize>,
+    pub prompt_eval_count: Option<u64>,
 
     /// Time spent evaluating the prompt in nanoseconds
-    pub prompt_eval_duration: Option<usize>,
+    pub prompt_eval_duration: Option<u64>,
 
     /// Number of output tokens generated in the response
-    pub eval_count: Option<usize>,
+    pub eval_count: Option<u64>,
 
     /// Time spent generating tokens in nanoseconds
-    pub eval_duration: Option<usize>,
+    pub eval_duration: Option<u64>,
 }
diff --git a/src/types/ps.rs b/src/types/ps.rs
index ebbc228..b5f735c 100644
--- a/src/types/ps.rs
+++ b/src/types/ps.rs
@@ -11,10 +11,10 @@ pub struct PsResponse {
 pub struct RunningModel {
     pub name: String,
     pub model: String,
-    pub size: usize,
+    pub size: u64,
     pub digest: String,
     pub details: ModelDetails,
     pub expires_at: String,
-    pub size_vram: usize,
+    pub size_vram: u64,
     pub context_length: u32,
 }
diff --git a/src/types/tags.rs b/src/types/tags.rs
index 6268623..90e209d 100644
--- a/src/types/tags.rs
+++ b/src/types/tags.rs
@@ -12,7 +12,7 @@ pub struct Model {
     pub name: String,
     pub model: String,
     pub modified_at: String,
-    pub size: usize,
+    pub size: u64,
     pub digest: String,
     pub details: ModelDetails,
 }