Rent Arrears Calculator

Missed rent does not sit still. Every month adds another full rent to the balance, late fees stack on top, and partial payments made along the way need to come back off. By the time anyone sits down to settle it, the real total is anyone’s guess, which is how disputes start. Enter the monthly rent, the months owed, any existing balance, any partial payments, and the late fee as a fixed monthly amount or a percent of rent, and you get an itemized statement of exactly what is owed, plus a monthly catch-up figure if you spread repayment over several months.

Quick Answer

How to use the rent arrears calculator

Enter the debt as it stands, then click Calculate. Nothing computes until you click, and the calculator above is pre-filled with the worked example.

1. Rent and months: the monthly rent from the lease and the number of months owed. The tool reads whole months, so 3.9 truncates to 3; a zero in months owed is accepted.
2. Balance and partials: any arrears carried forward from earlier periods, minus any payments already made toward the debt. The balance and partial rows only appear on the statement when they are greater than zero.
3. Late-fee type: pick the model your lease uses. A fixed dollar amount per month or a percent of rent per month, five percent being the common US figure.
4. The fee itself: the fee for one late month, in dollars or percent depending on the type. Blank counts as zero, and the fee row still prints so the statement is complete.
5. Repayment months, optional: divide the total into a monthly catch-up figure. Leave it blank for no plan; entering zero behaves the same way.
6. Share the statement: the copy button turns the itemized result into text you can send the other party, and the share button does the same through your device's share sheet.

The formula: one total, four moving parts

The arithmetic is a single statement with no hidden steps.

The repayment plan divides the total by your chosen months: Monthly Catch-Up = Total Arrears / Repayment Months. If you are also comparing the cost of staying versus moving, the half buy half rent calculator models the split-tenure math that sometimes follows a big arrears figure.

Worked example: four verified runs

The pre-filled run is the worked example: rent $1,500, 3 months owed, a $200 existing balance, $500 in partials, and a 5% monthly fee. Base rent is 1,500 × 3 = $4,500, late fees are 1,500 × 0.05 × 3 = $225, and the total is 4,500 + 200 − 500 + 225 = $4,425.00, or $737.50 a month over a 6-month plan. Every row below is a verified run of the calculator above:

The last run shows the zero floor at work: $1,000 of rent minus $1,500 of partials plus $50 of fees would be negative, so the tool reports $0.00 instead of a negative balance. That is a display choice, not a legal one: an overpayment may be a credit, and the lease controls that, not this tool.

The two late-fee models, honestly

US leases mostly use one of two models, and this tool implements both. A fixed fee is a flat dollar amount for each late month: simple to communicate, awkward when one policy covers a $900 unit and a $2,500 unit. A percent fee scales with rent, commonly around 5%: $75 on $1,500 of rent per late month, multiplied by every month owed.

Two things this tool does not model, stated plainly. First, daily fees: some leases charge per day late (Iowa, for instance, allows up to $12 or $20 a day with a monthly cap), and those need a days-late input this tool does not have. Second, grace periods: the window after the due date before rent counts as late, commonly 3 to 5 days and mandatory in some states. The tool applies fees from the first month owed, so if your lease has a grace period, confirm whether the first month's fee should really apply. For penalties beyond ordinary late fees, the lease penalty calculator handles the broader penalty structures this page stays out of.

Partial payments: the field competitors skip

Most arrears tools treat the debt as a single number, which forces you to do the partial-payment subtraction by hand and invites exactly the arithmetic disputes this page exists to prevent. Here the partials have their own field and their own line on the statement, so the other party can see the $500 that already came off. The math treats a partial as a straight reduction of the debt with no fee adjustment, which is the honest default: whether a partial payment stops further fees from accruing is a lease question, and if your lease says otherwise, that belongs in the balance figure you enter, not hidden in the tool.

What competing calculators miss

The arrears corner of the web is thin, and each rival covers only part of the job:

• UtilityProfit's rent late fee calculator: the best fee reference going, with three fee models and state-by-state rules for 2026. It is a late-fee tool, not an arrears tool: it never totals missed rent, balances, or partials, and it offers no repayment plan.
• BraveCalculator's late rent calculator: flat plus daily fees with a grace period, worked on dates, the closest thing to a proper US late-fee workflow. It handles one late payment at a time, with no existing balance, no partial payments, and no multi-month repayment figure.
• SavvyCalculator's rent arrears calculator: the nearest direct rival, with the same months-times-rent-plus-percent-fees core. Percent fees only, no fixed-fee option, no existing balance, no partial-payment subtraction, and no repayment plan.
• The Independent Landlord (UK): the only source with a principled daily-interest method: the Bank of England base rate plus 3% per day under the Tenant Fees Act 2019. It is a prose formula for one month's rent, and the author admits multi-month math gets complicated. US leases rarely use it.
• Propertyware and winTAR documentation: professional late-fee posting inside property-management software, with per-tenant ledgers and flat-or-percent rules. Enterprise software help files, not a tool either side of a dispute can open in a browser.
• The gap this page fills: the only calculator that combines an existing balance, real partial-payment subtraction, a choice of fixed or percent monthly fee models, and a repayment-plan figure that turns an intimidating total into a negotiable monthly number, with the itemized breakdown doubling as a statement both parties can read.

If the arrears figure becomes an eviction question rather than an arithmetic one, the rules change completely: holdover rent covers the separate case of rent owed after a lease ends, and accelerated rent models the landlord remedy where the whole remaining balance comes due at once. For tenants checking whether the rent itself is affordable going forward, the 40x rent rule calculator is the usual US income test.

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