Use the following T-SQL script to get the transaction log size and log space used of your database.
SELECT DB_NAME(database_id) AS DatabaseName ,
CAST(( total_log_size_in_bytes / 1048576.0 ) AS DECIMAL(10, 1))
AS TotalLogSizeMB ,
CAST(( used_log_space_in_bytes / 1048576.0 ) AS DECIMAL(10, 1))
AS LogSpaceUsedMB ,
CAST(used_log_space_in_percent AS DECIMAL(10, 1)) AS LogSpaceUsedPercent
FROM sys.dm_db_log_space_usage;