Flatmate Rent & Bills Splitter
Split rent and bills fairly between flatmates. Weight by room size, ensuite, and usage share. Generate a flatmate agreement summary.
About this calculator
This calculator implements NZ flatmate cost sharing best practice from Tenancy Services NZ. Last consulted 18 May 2026. Verify the figures yourself by following the link.
NZ flatting cost benchmarks
Tenancy Services + Stats NZ 2026- •Median Auckland rent (3-bed): $720-820/wk
- •Median Wellington rent (3-bed): $650-750/wk
- •Median Christchurch rent (3-bed): $540-630/wk
- •Typical shared bills: $100-180/wk (power+internet+water)
- •Ensuite room weighting: +30% vs standard room
- •Letting fees (banned 2018): Illegal — never pay these
Source: Tenancy Services NZ
Disclaimer
This calculator provides estimates for general information purposes only. Results are based on standard formulas and may not reflect your individual circumstances. Always consult a qualified professional for advice specific to your situation.
How fair flatmate splits are calculated
Two weights: rent by room (size + ensuite), bills by usage share. Each person gets their share of each.
- 1
Room-weighted rent
Rent_weight = rooms + (0.3 if ensuite)
Bigger room + ensuite → larger share.
- 2
Allocate rent
Person_rent = weekly_rent × person_weight ÷ total_weights
Sum of all weights = denominator.
- 3
Usage-weighted bills
Bill_weight = personal usage factor (1.0 = average, 2.0 = double, etc.)
Heavy users (long showers, EV charging) take a larger share.
- 4
Total per person
Person_total = person_rent + person_bills
Write into flatmate agreement.
Worked example
Inputs: Rent $850, bills $120, 3 people (one with ensuite)
Result: Ensuite person pays $850 × 1.3 ÷ 3.3 = $335 rent. Others $258 each. Bills $40 each.
Frequently Asked Questions
How should flatmates split bills fairly?
Should partner stay-overs affect the bill split?
What's the maximum bond a NZ landlord can charge?
How do flatmates usually split power and internet bills in NZ?
The flatmate rent and bills splitter divides weekly rent and shared bills fairly between flatmates, weighting rent by room size and ensuite access, and bills by each person's actual usage.
How this calculator works
Splitting everything evenly feels simple but rarely feels fair when one room is twice the size or has its own ensuite. This tool uses two separate weightings. Rent is allocated by room weight — a standard room counts as 1.0 and an ensuite adds about 0.3, so the ensuite room carries a larger share of the weekly rent. Bills are allocated by usage factor: someone who works from home all day, takes long showers, or charges an EV can be weighted at 1.5× or 2× while everyone else stays at 1.0. Each person's total is their rent share plus their bills share — write the agreed numbers into your flatmate agreement. Remember that in NZ, flatmates who are not on the tenancy agreement are not covered by the Residential Tenancies Act, so a written flatmate agreement is your main protection, and letting fees have been illegal since 2018.
NZ flatting benchmarks 2026
| Median Auckland rent (3-bedroom) | $720 - $820/week |
| Median Wellington rent (3-bedroom) | $650 - $750/week |
| Median Christchurch rent (3-bedroom) | $540 - $630/week |
| Typical shared bills (power + internet + water) | $100 - $180/week |
| Ensuite room weighting | +30% vs a standard room |
| Letting fees | Banned since 2018 — never pay them |
Worked Examples
Rent $850/week, bills $120/week, 3 flatmates — one has the ensuite room
Ensuite room pays $335/week rent; the other two pay $258 each; bills $40 each.
- Weights: 1.0 + 1.0 + 1.3 (ensuite) = 3.3
- Ensuite share: $850 × 1.3 ÷ 3.3 = $335
- Standard rooms: $850 × 1.0 ÷ 3.3 = $258 each
- Bills split evenly: $120 ÷ 3 = $40 each
Rent $720/week, 2 flatmates with equal rooms, but one works from home and uses 1.5× the power ($150/week bills)
Rent $360 each; bills split $90 / $60 by usage.
- Equal rooms: $720 ÷ 2 = $360 rent each
- Bill weights: 1.5 + 1.0 = 2.5
- Heavy user: $150 × 1.5 ÷ 2.5 = $90
- Light user: $150 × 1.0 ÷ 2.5 = $60
Built and maintained by Konstantin Iakovlev. Data sourced from the IRD and official New Zealand government sources.
Last reviewed: