1---
2app_version: 0.1.0
3precision: 2
4form_title: Electricity bill — back-payment ahead?
5form_description: Read your meter today and know months before the bill arrives. Enter the reading from your last bill, today's reading and your tariff to see the projected yearly cost, the expected back-payment or refund, and the monthly advance that would fit.
6form_inputs: Meter at last bill|reading_then{kWh}, Meter today|reading_now{kWh}, Days since last bill|days_since, Price per kWh|price{€/kWh}, Base fee per month|base_fee{€}, Monthly advance|advance{€}
7form_outputs: Projected use per year|per_year, Projected cost per year|cost_year, Advance paid per year|paid_year, Back-payment (+) or refund (−)|balance, Advance that would fit|fair_advance
8---
9# Electricity bill — back-payment ahead?
10// Read the meter now instead of waiting for the bill. This notebook also has
11// a FORM (Pro): Form → Form view for an input mask.
12
13# Meter readings
14reading_then = 41250 kWh // on the last bill
15reading_now = 43480 kWh // read today
16days_since = 240 // days between the two readings
17
18# Tariff
19price = 0.34 €/kWh
20base_fee = 12 € // per month
21advance = 100 € // what you pay each month
22
23# Projection
24// kWh × €/kWh cancels to €, no manual conversion anywhere.
25used = reading_now - reading_then
26per_year = used / days_since * 365
27cost_year = per_year * price + base_fee * 12
28paid_year = advance * 12
29balance = cost_year - paid_year
30fair_advance = cost_year / 12
31"Projected use per year": per_year
32"Back-payment (+) or refund (−)": balance
33"Advance that would fit": fair_advance
34// Winter uses more power than summer: a reading taken right after a winter
35// overstates the year a little, one taken after a summer understates it.
36