Rent tools and guides

Choose a calculation, prepare a letter, or check the assumptions behind a rental charge.

Updated October 25, 2026Methodology & sources

Calculate a payment

Prorated rentMove-in or move-out rent with three day-count methods.General prorationDivide any amount across a chosen service period.Net effective rentSpread a stated concession over the lease term.Late fee calculationCompare the fee terms you enter, with no legal default.Rent increaseFind the changed rent or reverse the percentage.Three-times-rent checkConvert a chosen gross-income ratio.Rent versus sellCompare your property assumptions and cash flows.

Prepare a letter

Rent increase noticeEdit a draft after checking the amount, timing and delivery rules.Deposit return letterPrepare an itemized accounting and refund record.Deposit request letterExplain a missing refund or disputed deduction.

Understand the calculation

What prorated meansFour clear examples for rent, pay, fees and refunds.What prorated rent meansHow a partial rental period becomes a charge.How to calculate prorated rentWork through the denominators and boundary dates.Prorated rent when moving outCheck the final day, handover date and counted period.Understanding rent late feesCompare fee structures without assuming a national average.Understanding annual rent increasesDistinguish a one-year change from a multi-year average.

California rules

California rent increasesThe covered-tenancy cap, exemptions and notice questions.California security depositsThe 2026 payment changes and move-out accounting.

Calculations show arithmetic under your assumptions. Letters are editable drafts. The methodology and sources explain the scope; report a correction if something does not match the published method.