Electricity Split Calculator
Splitting rent already? Work out a fair way to divide the power bill between roommates too.
Calculate Electricity SplitRent Split Calculator
Splitting rent evenly isn't always fair when rooms aren't equal. Start from an equal share, then adjust for room size, the master bedroom, and a private bathroom — the calculator instantly works out a fair share for everyone.
Total Rent
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Equal Share (before adjustments)
Roommates
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How this calculator works
An even split isn't always fair when rooms aren't equal — a bigger room, the master bedroom, or a private bathroom is usually worth paying a bit more for. This calculator starts everyone at an equal share, then adjusts up or down based on each roommate's room.
1. Equal share — the starting point, before any adjustments:
equal_share = total_rent ÷ roommates
2. Adjusted share — each roommate's equal share, adjusted for their room:
adjusted_share = equal_share + premium_for_better_room
Room size, master bedroom, and private bathroom are independent, stackable adjustments — for example, a roommate with the master bedroom and a private bath gets both premiums applied. A roommate with a smaller room gets the room size percentage subtracted instead.
3. Rebalancing — because premiums add money and discounts remove it, the raw adjusted shares are rescaled proportionally so the roommates' shares always add up to exactly the total rent — nobody pays more or less than the whole amount between them.
Example calculation — using this calculator's default values: $2,400 total rent split between 3 roommates, with a 10% room size adjustment, a 15% master bedroom premium, and a 5% private bathroom premium. By default, Roommate 1 has the larger room, the master bedroom, and a private bath; Roommate 2 has a smaller room; Roommate 3 has a standard room:
equal_share = 2400 ÷ 3 = $800.00
Roommate 1 (larger + master + bath) = 800 × (1 + 0.10 + 0.15 + 0.05) = 800 × 1.30 = $1,040.00
Roommate 2 (smaller) = 800 × (1 − 0.10) = 800 × 0.90 = $720.00
Roommate 3 (standard) = 800 × 1.00 = $800.00
tentative total = 1040 + 720 + 800 = $2,560.00
scale = 2400 ÷ 2560 = 0.9375
Roommate 1 final = 1040 × 0.9375 = $975.00
Roommate 2 final = 720 × 0.9375 = $675.00
Roommate 3 final = 800 × 0.9375 = $750.00
With these defaults, Roommate 1 (largest room, master bedroom, private bath) pays $975.00/month, Roommate 2 (smaller room) pays $675.00/month, and Roommate 3 (standard room) pays $750.00/month — the three shares add up to exactly the $2,400 total rent.
Factors That Affect Your Rent Split
Room size differences
A noticeably bigger or smaller room is the most common reason roommates adjust an even split. Set the "Room size difference" percentage to reflect how much extra space is actually worth to your household, then mark each roommate's room as larger, smaller, or standard.
Master bedroom premium
The master bedroom is usually the largest room and often comes with extra closet space or its own entrance, which is why it typically carries the biggest premium of the three adjustments — commonly 10–20% of the equal share.
Private bathroom access
Not having to share a bathroom is a real convenience worth paying a little extra for. This premium is usually smaller than the master bedroom premium, but it stacks on top of any other adjustments that roommate already has.
Number of roommates
The equal share is total rent divided by the number of people in the home, so adding or removing a roommate changes everyone's starting point before any room-based adjustments are even applied.
Shared vs. private space
This calculator only adjusts for each roommate's own room, not shared common areas like the living room or kitchen. Households with very little shared space (a studio-style layout) may want smaller premiums than households with a large, separate living room everyone uses equally.
Tips for a Fairer Rent Split
Agree on the split method before signing a lease
Talk through room size, master bedroom, and bathroom premiums with everyone before anyone signs anything. It's much easier to agree on a fair method up front than to renegotiate after move-in.
Revisit the split if someone changes rooms
If a roommate moves into a different bedroom, swaps into the master, or gains or loses access to a private bathroom, rerun the calculator with the updated room assignments so the split still reflects reality.
Put the agreed split in writing
Once everyone agrees on a fair split, write it down — in a roommate agreement, a shared document, or even a group chat message everyone confirms. This avoids confusion or disputes later, especially if someone moves out and a new roommate joins.
Split utilities separately
This calculator only covers rent. Utilities like electricity often make more sense to split by usage or a different method entirely — try the Electricity Split Calculator to work out a fair share of the power bill.
Limitations of This Estimate
This calculator gives you a reasonable starting point for a conversation, not a binding or "correct" answer. Fairness is subjective — what feels like a fair premium for the master bedroom or a private bathroom is ultimately something roommates need to agree on together, not something a formula can settle on its own.
It also only accounts for room size, master bedroom status, and private bathroom access. Other amenities that might justify a premium — a dedicated parking spot, extra storage space, yard or balcony access, or a walk-in closet — aren't factored in automatically. If those matter to your household, build them into the room size or premium percentages you enter manually.
Frequently Asked Questions
Room premiums and discounts are applied first, then every roommate's share is rescaled proportionally so the totals always match your total rent exactly — no more, no less. This keeps the split fair without anyone accidentally overpaying or underpaying the landlord.
Yes. Room size, master bedroom, and private bathroom are independent settings per roommate, and their percentages stack. A roommate with the largest room, the master bedroom, and a private bath will see all three premiums applied together.
There's no universal rule, but common starting points are a 10–20% premium for the master bedroom, a 5–10% discount for a noticeably smaller room, and a smaller premium (often 5% or so) for a private bathroom. Adjust these to whatever feels fair for your specific apartment.
Leave every roommate set to "Standard room" with no master bedroom or private bathroom checked, and the calculator will simply split the rent evenly between everyone.
Most households start with an equal split and then adjust for meaningful differences — a bigger room, the master bedroom, or a private bathroom. This calculator automates that process: it starts everyone at an equal share, applies the adjustments you set for each roommate, then rescales so the total still matches your rent exactly.
A 10–20% premium on top of the equal share is a common range, since the master bedroom is typically the largest room and often has extra features like more closet space. The right number depends on how much bigger and more private the master actually is compared to the other rooms in your specific apartment.
Many households add a small premium — often around 5% — for a roommate who doesn't have to share a bathroom, since it's a meaningful convenience. It's usually smaller than the master bedroom premium, but you can adjust the "Private bathroom premium" field to whatever feels right for your home.
Set "Number of roommates" to however many people are splitting the rent (this calculator supports 2–8), then set each roommate's room size, master bedroom status, and private bathroom access individually. The equal share and all adjustments automatically recalculate for the new group size.
This calculator doesn't measure exact square footage — it just asks whether a room is larger, smaller, or standard relative to the others. If a room has noticeably more closet or storage space than the rest, it's reasonable to factor that into whether you mark it as "larger" and by how much you set the size difference percentage.
Use this calculator's numbers as a starting point for a conversation, not the final word. Try adjusting the percentages together until everyone feels the result is reasonable — since fairness here is subjective, the goal is a split everyone can agree to live with, not a single "correct" answer.
No — this tool only splits rent. Utilities like electricity are often fairer to split by a different method, such as usage or a flat per-person share. Use the Electricity Split Calculator to work out a fair share of the power bill separately.
Mark that roommate's room as "Smaller room" and increase the "Room size difference" percentage if the gap is significant — a noticeably smaller room might justify a bigger discount than the default 10%. The calculator will subtract that percentage from their equal share before rescaling everyone's totals.
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