How to calculate the utility bill for the apartment?
Simple instructions for calculating service bills. Learn how to properly divide the costs of heat, water and other services between tenants.
TL;DR – Quick Answer
You calculate the utility bill by dividing the total cost of each service among the apartments according to the specified key (area, persons, meters). You will deduct the paid deposits from the tenant's share. Positive difference = overpayment (you refund), negative difference = underpayment (tenant pays extra).
Basic billing formula
All service billing is based on one simple principle:
Actual costs − Advances paid = Overpayment/Underpayment
It sounds simple, but the devil is in details. Let's break it down.
Step 1: Find out the total costs
The first thing you need are invoices for all the services for the whole house.
List of services to be billed
- Heat - invoice from heating plants or gas/electricity costs for the boiler
- Hot water - water heating (often part of the heat invoice)
- Cold water and sewage – invoice from the water works
- Electricity of common areas – invoice from the electricity supplier
- Cleaning – invoices for the cleaning company or agreement on the execution of work
- Waste collection – fee from the municipality/collection company
- Elevator operation – service, inspection, electricity for the elevator
- Other – according to rental contracts (cable, internet, security...)
Example
| Service | Invoice for the year | Note |
|---|---|---|
| Heat | 180,000 Kč | Heating plant invoice |
| Hot water | 35,000 Kč | Central heating |
| Cold water | 45,000 Kč | Waterworks |
| Common-area electricity | 12,000 Kč | ČEZ |
| Cleaning | 18,000 Kč | Mrs. Nováková |
| Waste | Kč 8,000 | Fee to the municipality |
| Total | 298,000 Kč |
Step 2: Determine the Billing Key
This is where things get interesting. Each service is billed differently.
Heat
Rules according to Decree No. 269/2015 Coll.:
- A basic component according to the current heat-allocation decree and the building's applicable method
- The corresponding consumption component according to measured values and the current decree
A 40:60 split is used below only as an illustration; the applicable ratio depends on the building and current decree.
Calculation for the apartment:
Total area of the house: 500 m² Area of the apartment: 65 m² Consumption of the apartment according to meters: 15% of the total
Illustrative calculation using the example's 40:60 split: basic component 180,000 × 0.4 × (65/500) = Kč 9,360; consumption component 180,000 × 0.6 × 0.15 = Kč 16,200. Total heat: Kč 25,560
Cold water
According to meters (if any) or according to the number of people
Meters:
- Apartment consumption: 45 m³
- Total price per m³: 95 Kč (water + sewage)
- Costs: 45 × 95 = 4,275 Kč
Without meters (according to persons):
- Persons in the apartment: 2
- Total persons in the house: 24
- Costs: 45,000 × (2/24) = 3,750 Kč
Hot water
Combination:
- a basic component set under the current heat-allocation rules; the percentage depends on the building and applicable decree
- the remaining consumption component under the current heat-allocation rules; hot-water allocation is calculated separately
Calculation: Illustrative calculation only: apply the hot-water components and percentages required by the current decree and the building's allocation method; do not treat 30%/70% as universal. Hot water in total: 3,325 Kč
Electricity in common areas
According to floor area
Costs: 12,000 Kč Share of apartment: 65/500 = 13% Costs of an apartment: 12,000 × 0.13 = 1,560 Kč
Cleaning
Equally or according to area
Equally (12 apartments): Cost of an apartment: 18,000 / 12 = 1,500 Kč
Removal of waste
According to the number of people (most often)
Persons in the apartment: 2 Total people: 24 Costs of the apartment: 8,000 × (2/24) = 667 Kč
Step 3: Add up the costs of the apartment
| Service | Apartment costs |
|---|---|
| Heat | 25,560 Kč |
| Cold water | 4,275 Kč |
| Hot water | Kč 3,325 |
| Common-area electricity | 1,560 Kč |
| Cleaning | 1,500 Kč |
| Waste | 667 Kč |
| Total | 36,887 Kč |
Step 4: Compare the down payments
The tenant paid monthly down payments of 3,200 Kč.
Down payments for the year: 3,200 × 12 = 38,400 Kč
Actual costs: 36,887 Kč
Difference: 38,400 - 36,887 = 1,513 Kč overpayment
Special situation
The tenant moved in during the year
You only count for the period when he lived in the apartment.
Example: Moving in: 1. April Period: April–December = 9 months
For services by area: whole amount × (9/12) For services by meters: according to actual consumption during the period Deposits: only those paid by the tenant
Change in number of persons
Average number of persons per period.
Example: January–June: 2 persons July–December: 3 persons
Diameter: (2×6 + 3×6) / 12 = 2.5 persons
Empty apartment
I empty apartment applies:
- Basic component of heat (heats even if nobody lives there)
- Electricity of common areas (light on the corridor is lit)
- Cleaning (the corridors are being cleaned)
Does not apply:
- Consumption component of water (no consumption is measured)
- Garbage (if payment is per person)
Checking the calculation
Check 1: The sum must equal the total
Add up the costs of all apartments. The total cost of the house must come out.
Check 2: The shares must give 100%
The sum of the shares of all apartments (in percentages) must be 100%.
Check 3: Comparison with last year
If the costs are significantly different from last year, find out why:
- Change in energy prices?
- Other consumption?
- Error in the calculation?
Formulas for quick calculation
By area
`` Flat cost = Total cost × (Flat area / Total area) ``
By persons
`` Flat cost = Total cost × (Number of people in the flat / Total number persons) ``
By meter
`` Flat cost = Flat consumption × Price per unit ``
Combined (heat)
`` Basic = Total cost × 0.4 × (Flat area / Total area) Consumable = Total cost × 0.6 × (Flat consumption / Total consumption) Flat cost = Basic + Consumption ``
Frequent errors in calculations
Error 1: Forgotten service
You bill heat, water, but forget cleaning. The tenant also paid deposits for cleaning, but you do not bill him. An unauthorized overpayment occurs.
Error 2: Wrong units
You are using m³ instead of m². Or you calculate consumption in liters, but the invoice is in m³.
1 m³ = 1000 liters
Error 3: DPH
The invoice includes VAT, but you calculate without VAT. Or vice versa.
Rule: Always calculate the total amount of the invoice including VAT.
Error 4: Wrong number of people
In January 2 people lived, in February 3, in March again 2. And you use 3 for the whole year.
Solution: Calculate the average or weighted average by months.
Error 5: Crediting the previous period
You cannot include the arrears from last year in this year's bill. They are two separate claims.
Example of a complete calculation
Input data:
- Apartment: 65 m², 2 persons
- Entire house: 500 m², 24 persons, 12 apartments
- Water consumption (meter): 48 m³
- Heat consumption (meter share): 14% from the total
Calculation:
| Service | Total house | The way | Calculation | Flat load |
|---|---|---|---|---|
| Heat | 180,000 | 40/60 | 72000×(65/500) + 108000×0.14 | 24 480 |
| St. water | 45,000 | meter | 48 × (45000/450) | 4,800 |
| Hot water | 35,000 | current allocation method (illustrative) | calculated under the applicable decree | 3,815 |
| Electricity | 12,000 | area | 12000×(65/500) | 1,560 |
| Cleaning | 18,000 | flats | 18000/12 | 1,500 |
| Waste | 8,000 | persons | 8000×(2/24) | 667 |
| Total | 36,822 |
Advances: 3,100 × 12 = Kč 37,200 Result: Overpayment Kč 378
How Grento helps you
Grento calculates the bill automatically according to the set billing rules and generates clear documents for tenants.
- Automatic calculations - you enter meter statuses, the system calculates
- Correct formulas - according to valid legislation
- Control - the system reports irregularities
- History - comparison with previous years
- Export - billing as PDF
Summary
Procedure billing calculation:
- Find total cost from
2 invoices. Specify billing key for each service
- Calculate the apartment share according to the formula
- Total costs for all services
- Compare with advances = overpayment/underpayment
- Check the totals and compare to last year
The math is simple. It is more difficult to collect all the documents and use the right keys. But now you know how!
> Czech-law scope and editorial note: Legal, tax, accounting, tenancy, service-charge, condominium, metrology, insurance and data-protection statements in this article refer to the Czech Republic and the rules effective for the relevant date. Figures and examples are illustrative, not legal or tax advice. Verify current rules with the relevant Czech authority or a qualified adviser.
> Service-accounting clarification: Under Czech Act No. 67/2013 Coll., distinguish delivery of the settlement within four months after the accounting period, financial settlement generally within four months after delivery, and the separate 30-day periods for supporting documents or objections under § 8. A statutory per-day penalty under § 13 is conditional; verify the current amount and cap rather than applying a universal figure.
> Metrology and heat clarification: Verification periods depend on the instrument type and current UNMZ rule. Heat allocation uses the current Czech decree and may use a 40%, 50% or 60% basic component according to building energy performance, with possible adjustments; hot-water allocation is separate. Do not treat a 30/70 or ±20% statement as universal.