How to use the MSE, RMSE and MAE Calculator
- 1. Paste your valuesOne actual and one predicted value per line, separated by spaces, commas or tabs.
- 2. Add a unitOptionally add the unit, such as ₹ thousand or kg, so results are labelled.
- 3. Compare errorsRead RMSE, MAE, MSE, MAPE and the rest, plus the error on every row.
Which metric to use
MAE is the average size of the error, in your data's unit, and treats every miss equally. MSE squares errors, so big misses count much more; RMSE is its square root, back in the original unit. If RMSE is much bigger than MAE, a few large errors dominate. MAPE expresses error as a percentage of the actual value, which is easy to explain but undefined when an actual value is 0. Rows with an actual value of 0 are skipped and noted. The mean error (bias) shows whether predictions run high or low on average.
Worked example
The default is a sales forecast in ₹ thousand for six stores: actual 120, 150, 90, 200, 175 and 60 against predicted 110, 160, 95, 180, 170 and 72. The errors are −10, +10, +5, −20, −5 and +12. MSE is 132.3333, RMSE 11.5036 and MAE 10.3333. The median absolute error is 10, the largest miss is 20 and MAPE is 8.90%. Bias is −1.3333, so the forecast runs slightly low on average, and R² is 0.9428.
Checked against scikit-learn
On 30 random datasets, MSE, RMSE, MAE, median absolute error and MAPE match scikit-learn's mean_squared_error, mean_absolute_error, median_absolute_error and mean_absolute_percentage_error. Values are rounded to 4 decimal places on screen.
Frequently asked questions
Should I report RMSE or MAE?
Report both if you can. Use RMSE when large errors are especially costly; use MAE when you want a robust, easy-to-explain average error.
Why is MSE in squared units?
Because errors are squared. That's why RMSE, its square root, is easier to interpret.
Is the MSE, RMSE and MAE calculator free?
Yes. You can open the MSE, RMSE and MAE calculator and enter all your numbers without signing up. When you calculate errors for the first time, we ask once for your name and WhatsApp number; after that it, and every other Uncodemy tool, opens straight away.