Guide · 6 min read

    Bookkeeping for contractors

    Contractors don't fail from lack of work — they fail from not knowing which jobs make money. Here's how to keep books that show real margin per job, not just deposits in the bank.

    The contractor bookkeeping system

    1. 1

      One business account, one card

      Free business checking + a business credit card. Customer deposits in, sub payments and materials out. No more 'is this work or personal?'

    2. 2

      Job-cost every transaction

      Tag each expense to a job: materials, sub labor, permits, equipment rental, mileage. At job close you'll see real gross margin — not guesses.

    3. 3

      Collect W-9s before paying subs

      Any sub paid $600+ in a year needs a 1099-NEC by January 31. Get the W-9 before the first check goes out — chasing them in January is brutal.

    4. 4

      Quarterly taxes + retirement

      Move 25–30% of net profit to a tax savings account. Above $80k net, a SEP-IRA or Solo 401(k) can shelter $20–60k of taxable income.

    Deductible contractor expenses

    Materials & supplies
    Subcontractor payments
    Equipment & power tools
    Equipment rental
    Vehicle / mileage (70¢/mi)
    Fuel (if not using mileage)
    Trailer & truck maintenance
    General liability insurance
    Workers' comp
    License & permit fees
    Bonding fees
    Continuing education
    Office / yard rent
    Software (estimating, scheduling)
    Phone & internet
    Safety gear & uniforms

    Know real profit per job

    Tag expenses to jobs, capture sub payments, and see margin instantly. Built for the field, not for accountants.

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    Related

    FAQ

    What's the simplest way for a contractor to do bookkeeping?+

    One business checking account, one business credit card, and a job-costing system. Tag every expense to a specific job — materials, sub labor, permits, mileage. At the end of every job you'll know if it actually made money, not just whether the deposit hit.

    Do general contractors need job costing?+

    Yes. Without job-level cost tracking, you can only see whether the business made money overall — not which jobs are profitable. Most contractors discover after switching to job costing that 20% of jobs are losing money and need a price rethink.

    How are contractor taxes different?+

    Self-employment tax (15.3%) plus federal/state income tax, all paid quarterly. You can deduct materials, sub payments, equipment depreciation, vehicle/mileage, insurance, licenses, permits, and a portion of your home if you have a dedicated office. 1099-NECs go to every sub you paid $600+.

    Cash or accrual for a contracting business?+

    Most small contractors use cash basis (simpler — you record income when paid). Above $27M in average revenue you must use accrual. If you take large deposits on long jobs, talk to a CPA about percentage-of-completion accounting.

    When do I need to issue 1099s to subs?+

    Any subcontractor paid $600 or more in a calendar year gets a 1099-NEC by January 31. Collect a W-9 BEFORE you pay any sub — chasing them in January is miserable. LLCs taxed as S-corps don't need a 1099 (the W-9 tells you).