Thought I share this here. Hope someone finds it useful. Created on Excel 365 16.102 (macOS).

This is a TNB usage Excel Spreadsheet for old, new tariff non-ToU and ToU.
• table to enter your daily 30-min usage data
• it'll use the correct AFA for both months (hopefully)
• support for off-peak public holidays
• single cell formulas
• calculation may be off if used for less a full billing period (28, 30, 31 days)
• sometimes still off by 1 sen (rounding error somewhere)

Where to Enter your TNB CSV Data


Features

TNB Usage Stats Mainly to see your peak percentage before changing to ToU. My initial objective before I went overboard. Excel is quite addictive.

Date and Period Slicers Slicers to quickly select the day or billing period that you want to examine.

Power Budgeting I use this to see how much more kWh I have for this month if I want to stay below 400 kWh. Maybe a bit too much micro-managing.

Tariff Comparison Compare bills in different domestic tariffs; old, non-ToU & ToU. This is where the single-cell formulas for the 3 tariffs are used.

Bill Breakdown It's the same as your paper bill.

Graphs One of the sample graphs to compare day before and yesterday's usage by hour. Can change the PivotChart fields to compare all sorts of things. Use the Timeline to set the days.

More Graphs This one is set to display the current month's daily usage.

How to update? Delete the existing sample data from the table and copy & paste your own data form the older spreadsheet.

Updates
20250914_1639:  TNB_Usage_Cost_20250914.xlsx.zip ( 302.86k ) Number of downloads: 33

• Fix date calc in the Forecast part of the sheet

20250913_1904:  TNB_Usage_Cost_20250913.xlsx.zip ( 303.12k ) Number of downloads: 7

• Played around with the Stats & Forecast bit of the spreadsheet.
• Fix a bug with number of days calculation.
• Trying to fix up the graphs with better slicers.
• Cleaned up a bit. Still messy, sorry.

20250910_1811:  TNB_Usage_Cost_20250910.xlsx.zip ( 268.38k ) Number of downloads: 28

• Deleted the code and all that since everything is in the Excel file.
• Update with screenshots and explanations.

20250910_1147:

• Uploaded Excel file. The single cell formulas are on the Tariff sheet.
• Now includes formulas for old, non-ToU & ToU.

This post has been edited by soonwai: Sep 14 2025, 05:00 PM

I think Tnb calculator is already comprehensive. It’s available at their website.

It includes the start and end date like yours too.

This post has been edited by bee88: Sep 5 2025, 07:49 AM

Means you never use the TNB calc more than once

The point of excel here is to have everything shown upfront

TNB own calculator, unless changed, need you to key in and select things again for everytime you want to change a single parameter

Yes, indeed. In fact I used it to double check my Excel before I got the bill and also I wanted something that can display results in a few rows at the same time.

In addition, after I got the official PDF bill, I noticed that the TNB web calc is off for 1 sen for the really simple calcs (a x b) like kapasiti and rangkaian. PDF bill, mcchin's Google Sheet and mine all give the same result. Only explanation I can think of is that the web calculator truncates instead of rounding those calcs.

20250910_1147:
• Uploaded Excel file to 1st post. The single cell formulas are on the Tariff sheet.
• Now includes formulas for old, non-ToU & ToU.

can make a How to guide for dummies?

I know where to download the daily usage data from mytnb..

but where do i input all those data in the excel?

Quick reply first, later I'll update first post with better instructions.

Look in the "Table" sheet. There's a Table1 there already with some sample data. Delete those rows and paste yours from the csv.

The table expects Date , Time , Total_kWh.

The csv is "Datetime , Peak_kWh , OffPeak_kWh , Total_kWh" (if already on ToU) or "Datetime , kWh , Total_kWh" (if on non-ToU)

Open the csv and split the Datetime to "Date , Time" using Excel's Data -> Text-to-Columns and keep just the last Total_kWh.

After that can paste into that Table1 on the Table sheet.

*Can also use Excel's Power Query to import the csv. I just found out about this so haven't tried yet.

*Updated first post with guide. More or less.

This post has been edited by soonwai: Sep 11 2025, 12:25 AM

Updated Excel File in first post. It's so awesome now. not.

20250913_1904
• Played around with the Stats & Forecast bit of the spreadsheet.
• Fix a bug with number of days calculation.
• Trying to fix up the graphs with better slicers.
• Cleaned up a bit. Still messy, sorry.

Victory!
Using the Forecast bit of the spreadsheet and checking and managing usage once a day. I managed to keep it below the target of 400 kWh for this month. The cool weather helped with decreased aircon usage for the last 9 days or so.



This post has been edited by soonwai: Sep 13 2025, 07:28 PM

i have used some of your info in the excel to create 1 to check OP and P

from this can determine to use TOU or non TOU better.



This post has been edited by angelgemini: Sep 15 2025, 06:15 PM

DOWNLOADED AND THANKS. NEED TIME TO EXPLORE.

Just wondering worth to apply TOU if past 6 month bill like this.

aircond mayb everynight 9+ to 11+. drum Washing machine mayb evening or morning,. shower heater as usual timing.

apr-64.7
may-85.85
jun-105
jul-67.15
aug-63.4
sep-72.95

I just received my first full bill after converted to ToU in early August.

I think non-ToU is better for me.

July 2025 (Non-ToU) : 376 kWh used - RM 89.75
September (ToU) : 362 kWh used - RM 95.15

I will monitor for October. If it's the same as September, will switch back to non-ToU

You took July bill which is combination of old tariff and new tariff. That’s not accurate.

Quick check new tariff non tou with 362kWh can already see you saved rm5. Do easy why not compare non tou new tariff calculator instead of comparing with old tariff / other months.

I used 306kWh as an example for non-ToU RM72.84 (couldn't get to exactly RM72.95.) Since your usage quite similar to mine so I used 18% peak. Of course, better if you can find out your own peak % from the data at myTNB web. Then just plug in the numbers into the Excel spreadsheet and compare ToU to non.

Save a bit lah. Of course, the more you spend, the more you save.

Also, since you are only 6kWh away from 300kWh, try to get it there. More savings because of higher ICT discount at 300kWh and below. Saving 6kWh over 31 days shouldn't be too difficult. I think you already managed that in August. 289kWh in Aug?

This post has been edited by soonwai: Sep 18 2025, 10:44 PM

As LaiN87 said, Jun/July bill not good to compare with because of old/new tariff transition. It's probably be cheaper than normal if the transition happened right in the middle of your billing period.

Aug/Sep also no good if this is your non-ToU/ToU transition bill. Unless you timed the transition date to day 29 of your billing period, it will be more expensive than normal because all your kWh will kena 8% SST.

Yeah I forgot new tariff was effective 1 July 2025.

Yeah forgot about the new tariff on 1 July 2025.

Is mytnb website kaput for everyone?

• Can't switch to other accounts.
• Account list empty
• Energy Usage dashboard gone
• Application Status empty

I guess their maintenance ending at 4pm yesterday didn't go so well.

App still working.

Slowly coming back.
20250921_1606
• Can't switch to other accounts✅
• Account list empty✅


This post has been edited by soonwai: Sep 21 2025, 04:06 PM

Energy Dashboard is back!



4 days MC didn't help at all.

This post has been edited by soonwai: Sep 25 2025, 01:16 AM

MC couldn't solve

This one need surgery & hospitalisation leave

Still need few clicks & crashes until you get what you want

When I try to use it, it needs life support and resuscitation.