diff --git a/README.md b/README.md
index 2d482dc1..a0834551 100644
--- a/README.md
+++ b/README.md
@@ -162,7 +162,7 @@ Once built, the UI is automatically served by the FastAPI backend:
 
 - **Dashboard**: `http://localhost:8000/`
 - **Login**: `http://localhost:8000/login`
-- **Models Management**: `http://localhost:8000/model
+- **Models Management**: `http://localhost:8000/model`
 - **Providers Management**: `http://localhost:8000/providers`
 - **Settings**: `http://localhost:8000/settings`
 
diff --git a/routstr/auth.py b/routstr/auth.py
index b1e16987..d5b8ed87 100644
--- a/routstr/auth.py
+++ b/routstr/auth.py
@@ -9,7 +9,7 @@ from sqlmodel import col, update
 from .core import get_logger
 from .core.db import ApiKey, AsyncSession
 from .core.settings import settings
-from .payment.cost_caculation import (
+from .payment.cost_calculation import (
     CostData,
     CostDataError,
     MaxCostData,
diff --git a/routstr/core/settings.py b/routstr/core/settings.py
index eb8e59a9..9f213a3f 100644
--- a/routstr/core/settings.py
+++ b/routstr/core/settings.py
@@ -114,7 +114,7 @@ def resolve_bootstrap() -> Settings:
                 )
             except Exception:
                 pass
-        # Map COST_PER_1K_* -> CUSTOM_PER_1K_*
+        # Map COST_PER_1K_* -> FIXED_PER_1K_*
         if (
             "COST_PER_1K_INPUT_TOKENS" in os.environ
             and "FIXED_PER_1K_INPUT_TOKENS" not in os.environ
diff --git a/routstr/payment/__init__.py b/routstr/payment/__init__.py
index 55f5a854..0ca1ed03 100644
--- a/routstr/payment/__init__.py
+++ b/routstr/payment/__init__.py
@@ -1,4 +1,4 @@
-from .cost_caculation import CostData, CostDataError, MaxCostData, calculate_cost
+from .cost_calculation import CostData, CostDataError, MaxCostData, calculate_cost
 
 __all__ = [
     "CostData",
diff --git a/routstr/payment/cost_caculation.py b/routstr/payment/cost_calculation.py
similarity index 100%
rename from routstr/payment/cost_caculation.py
rename to routstr/payment/cost_calculation.py
diff --git a/routstr/upstreams/upstream.py b/routstr/upstreams/upstream.py
index 9d3b1e35..638971dc 100644
--- a/routstr/upstreams/upstream.py
+++ b/routstr/upstreams/upstream.py
@@ -13,7 +13,7 @@ from fastapi.responses import Response, StreamingResponse
 from ..auth import adjust_payment_for_tokens
 from ..core import get_logger
 from ..core.db import ApiKey, AsyncSession, create_session
-from ..payment.cost_caculation import (
+from ..payment.cost_calculation import (
     CostData,
     CostDataError,
     MaxCostData,