TL;DR
Helcim is the strongest fit for most U.S. law firms processing under about $50K in monthly card volume. In our cost model (prices checked Oct 2026) it costs about $270 a month on $10K of online card payments, against $350 on Stripe, with no contract and no monthly fee. From about $50K a month, Stax is cheaper online: $1,200 a month at $50K against $1,275 on Helcim. Firms that already bill through Clio, MyCase or PracticePanther can use the payments built into those platforms, and Stripe fits firms building a custom client portal.
How we ranked
We weighted six criteria. Cost comes from our published model: a $50 average sale and a 60/40 credit and debit mix at $10K, $50K and $250K a month, with prices checked Oct 2026. Law firm tickets are usually larger, which lowers the weight of fixed per-sale fees, but the order between pricing models holds.
- Effective rate at $10K, $50K and $250K monthly volume. Calculated from each provider's published price plus our stated interchange estimate.
- Contract terms. Month-to-month preferred. Any termination fee over $250 was penalized.
- IOLTA configurability. Whether the processor can deposit gross transaction amounts to a trust account while pulling fees from an operating account. Your state bar's trust account rules decide how fees and chargebacks must be handled, so ask the bar and the provider in writing.
- Recurring billing and retainer support. ACH, card on file, automatic invoicing for evergreen retainers.
- Practice management integration. Native plug-ins with Clio, MyCase, PracticePanther, Smokeball.
- Settlement speed. Funds in the operating account inside 2 business days.
Interchange ranges come from Visa and Mastercard published schedules. Provider pricing was checked in Oct 2026; LawPay and PracticePanther in Nov 2026.
In our model, a firm taking $250K a month in online card payments pays about $6,125 a month on Helcim, $5,200 on Stax and $8,750 on Stripe's flat 2.9 percent plus $0.30. The Helcim to Stripe gap is $2,625 a month, or $31,500 a year.
At a glance
| Provider | Headline pricing | Contract | Settlement | Best for | Watch out for |
|---|---|---|---|---|---|
| Helcim | IC + 0.50% + $0.25 online; IC + 0.40% + $0.08 in person | None | Next business morning | Solo and small firms under about $50K/mo | Rate moves with card mix |
| Stripe | 2.9% + $0.30 online; 2.7% + $0.05 in person | None | 2 business days | Firms building custom client portals | Flat rate never drops without a custom deal |
| Stax | $99 to $199+/mo by annual volume + IC + $0.15 online; $0.08 in person | No cancellation fee stated; length not published | Next business day | Firms from about $50K/mo | Subscription wastes money at low volume |
| Payment Depot | Interchange-plus by quote; no prices listed | No cancellation fees; $0 setup | Not published | Firms willing to get a written quote | Full cost cannot be computed |
| Square | 2.6% + $0.15 in person; 2.9% + $0.30 online on paid plans (3.3% + $0.30 on Free); 3.5% + $0.15 keyed | None | Next business day | Solo practitioners under $20K/mo | Keyed rate punishes phone retainers |
| PayPal | PayPal Checkout 3.49% + $0.49; Advanced card 2.89% + $0.29 | None | To PayPal balance; free standard withdrawal | Consumer-facing firms accepting wallet payments | $0.49 fixed fee hurts small invoices |
Helcim
Helcim's pricing is interchange-plus with no monthly fee and no contract. Online transactions run interchange plus 0.50 percent plus $0.25. In-person runs interchange plus 0.40 percent plus $0.08. The markup steps down automatically as monthly volume crosses published thresholds, with no negotiation required. See Helcim's pricing page.
At $50K a month in online card payments, our model puts Helcim at 2.55 percent, or $1,275 a month, against 3.50 percent and $1,750 on Stripe. That is $475 a month less.
Helcim supports recurring billing (recurring payments add 0.4 percent), card on file, and ACH at 0.5 percent plus $0.25, capped at $6. Check whether your practice management software connects to it before switching. ACH support matters for retainers above $1,000, where the percentage delta over card pricing dwarfs the integration trade-offs.
We found no IOLTA product on Helcim's pricing page. Firms that use a general processor for trust deposits often keep separate accounts for trust and operating money so fees and chargebacks never touch client funds. Ask Helcim in writing how deposits, fees and chargebacks are routed, and check the setup against your state bar's rules.
Who it is for: solo and small to midsize firms that bill flat fees and want predictable, transparent costs.
Who should avoid it: firms that need instant payouts or one fixed, predictable rate per sale.
Stripe
Stripe charges 2.9 percent plus $0.30 for online card payments and 2.7 percent plus $0.05 in person on the default flat-rate plan. ACH is 0.8 percent capped at $5.00. Pricing is published at stripe.com/pricing.
Stripe's edge for law firms is the API. Practice management platforms sell their own payment products instead: PracticePanther, for example, lists 2.95 percent on all cards and 1 percent on eChecks for PantherPayments. If your firm has a custom intake form or a client portal built in-house, Stripe is the path of least resistance.
The cost trade is real. At $250K a month in online card payments, our model puts Stripe at $8,750 a month against $6,125 on Helcim and $5,200 on Stax.
We found no IOLTA product on Stripe's pricing page. A firm using Stripe directly for trust deposits has to confirm with Stripe how fees and disputes are kept away from client funds. Legal billing products advertise this as built in: LawPay markets trust account protection and IOLTA compliance, and PracticePanther says PantherPayments deposits retainer payments directly into trust accounts.
Who it is for: firms with a developer on staff, or firms building a custom client portal.
Who should avoid it: firms with no technical bandwidth and no need for the API, since the flat rate never drops without a custom deal.
Stax
Stax charges a monthly subscription of $99 up to $150,000 a year in volume, $139 from $150,000 to $250,000 and $199 or more above that, then passes interchange through with no percentage markup. Per-transaction fees are $0.08 in person and $0.15 online. Plan details live at staxpayments.com/pricing.
The subscription model favors firms whose card volume is high enough to spread the fee. At $80K a month the fee is $199 or more, about 0.25 percent of volume. In our model, Stax costs $1,200 a month on $50K of online card payments against $1,275 on Helcim, and $5,200 against $6,125 at $250K.
Below about $50K monthly volume, the math reverses. At $10K a month the $99 fee alone is 0.99 percent of volume, and Helcim wins: $270 a month online against $299 on Stax.
Stax supports recurring billing. We found no IOLTA product on its pricing page, so ask Stax in writing how trust deposits, fees and chargebacks are routed.
Who it is for: established firms with $50K or more in steady monthly card volume, especially those processing high-ticket invoices.
Who should avoid it: solo and small practices with seasonal or unpredictable billing.
Payment Depot
Payment Depot sells interchange-plus pricing by quote. Its pricing page (archived Oct 2025) lists no monthly or per-transaction price, so its full cost cannot be computed; it says $0 setup and no cancellation fees.
Ask for a written quote and compare it with Stax's published $99 to $199+ a month plus interchange before choosing.
Its pricing page does not state settlement timing, so ask before signing.
The catch is that no price is published. Read the agreement before signing, because any monthly fee that no longer fits your volume costs money every month.
Who it is for: firms with steady volume and predictable card counts that are willing to get a written quote.
Who should avoid it: firms with seasonal billing, where a slow quarter wastes any fixed monthly fee in the quote.
Square
Square charges 2.6 percent plus $0.15 in person, 3.3 percent plus $0.30 online on its Free plan (2.9 percent plus $0.30 on paid plans), and 3.5 percent plus $0.15 for keyed transactions. No monthly fee on the Free plan. Pricing at squareup.com/us/en/pricing.
Square works for solo attorneys who take occasional in-person retainer payments at the courthouse or in a client meeting. Hardware starts at $59, next-business-day deposits are free, and there is no contract. On a $400 in-person payment, 2.6 percent plus $0.15 is $10.55, or 2.64 percent. Helcim and PayPal POS cost less per sale in our model, so Square's case is its free app and fast setup, not price.
The keyed rate of 3.5 percent plus $0.15 is the problem. Most law firm card payments are taken over the phone for retainers or invoice settlements, and those land in the keyed bucket. At that rate, a $2,500 retainer costs $87.65 in processing.
Any processor can review or hold a payment that is much larger than an account's usual pattern. For trust account funds, that risk matters. If you plan to bill a $25,000 retainer on an account that usually processes $3,000 invoices, ask Square in advance how a large payment will be reviewed.
Who it is for: solo practitioners under $20K monthly volume with mostly card-present transactions.
Who should avoid it: firms doing card-not-present retainers or any IOLTA funds.
PayPal
PayPal Checkout charges 3.49 percent plus $0.49. Advanced Credit and Debit, which needs PayPal's approval, is 2.89 percent plus $0.29 for direct card payments. PayPal POS in person is 2.29 percent plus $0.09. See PayPal's business fees.
The $0.49 fixed fee is the issue for legal billing. On a $1,500 invoice, $0.49 is negligible. On a $75 filing-fee reimbursement paid through PayPal Checkout, 3.49 percent plus $0.49 is about 4.14 percent effective. On a $100 charge, a $0.49 fixed fee costs 0.39 percentage points more than a $0.10 fee would.
PayPal's strength is consumer trust. Some consumer clients prefer PayPal because they already have an account. For estate planning, family law, and immigration practices serving retail clients, accepting PayPal alongside a primary card processor is reasonable.
PayPal's fee page does not describe an IOLTA product, and its dispute process is built around buyer protection rather than B2B contract enforcement. Chargebacks cost $20. For trust account billing, route through a primary processor and leave PayPal as a backup channel.
Who it is for: consumer-facing firms that want a second payment option for clients who request it.
Who should avoid it: B2B legal practices and firms billing large flat fees, where the fixed fee disappears but the dispute exposure stays.
Verdict
For a U.S. law firm processing under about $50K in monthly card volume, Helcim wins on cost and contract terms. In our model it costs about $270 a month on $10K of online payments against $350 on Stripe, with no monthly fee and no termination clause.
Firms whose billing already runs through Clio, MyCase or PracticePanther can use the payments built into those platforms; compare their published rates (PantherPayments lists 2.95 percent on cards, LawPay 2.99 percent plus $0.30 and $19 a month) with Helcim and Stax. Stripe wins for firms building a custom portal. The flat rate costs more, but the integration work it saves can be worth it.
Stax wins from about $50K a month: in our model it costs $1,200 a month on $50K of online payments and $5,200 on $250K, the lowest of the providers on this page.
Whichever processor you pick, the trust account setup matters more than the headline rate. Make sure fees and chargebacks are drawn from the operating account, not client funds, get the provider's routing in writing, and check it against your state bar's rules before sending the first invoice.