R&D Tax Credit Calculation: A Step-by-Step Example

The federal R&D tax credit under IRC Section 41 can be calculated using two methods: the Regular Credit (RC) and the Alternative Simplified Credit (ASC). The Regular Credit compares your current-year qualified research expenses (QREs) against a base amount derived from historical data. The ASC, which most startups use, compares current-year QREs against the average of the prior three years. If the company had no QREs in any one of the three prior years, the ASC is 6% of current-year QREs. Most startups elect the ASC because the calculation is simpler and the base period is shorter.

Consider a SaaS startup with the following 2025 qualified research expenses (QREs). This is a hypothetical example.

• Employee wages: six engineers earn $840,000 in total and spend 70% of their time on qualifying research, so $588,000 qualifies.
• Contract research: two US-based development contractors are paid $120,000, and 65% of their work ($78,000) is qualified research. Only 65% of contract research counts under §41(b)(3), so $50,700 is included.
• Cloud computing for development and testing environments (the right to use computers in qualified research): $45,000.
• Supplies used in research: $12,000.

Total QREs for 2025: $695,700. Assume QREs for the prior three years were $400,000, $500,000 and $600,000, and average annual gross receipts for the prior four years were $2,000,000.

Note that the contractors are US-based. Research performed outside the United States is excluded from §41 entirely, so offshore development teams do not add to QREs.

Step 1: Calculate the average QREs for the prior three years. ($400,000 + $500,000 + $600,000) / 3 = $500,000. Step 2: Multiply the average by 50%. $500,000 x 50% = $250,000. Step 3: Subtract that amount from current-year QREs. $695,700 minus $250,000 = $445,700. Step 4: Multiply by the ASC rate of 14%. $445,700 x 14% = $62,398. The federal R&D tax credit for 2025 under the ASC method would be $62,398. If this is a C-corp with taxable income, that directly reduces your federal tax bill. If it is a qualified small business under Section 41(h), the credit (up to $500,000 a year) can instead offset employer payroll taxes.

The regular credit is 20% of current-year QREs above a base amount. The base amount is a fixed-base percentage times the average gross receipts of the prior four years, but it can never be less than 50% of current-year QREs.

Startups rarely have data from the 1984 to 1988 base period, so they use the start-up company rules: a 3% fixed-base percentage for each of the first five tax years with QREs, adjusted after that using the company's own history.

Step 1: Fixed-base calculation. $2,000,000 x 3% = $60,000.

Step 2: Minimum base amount. $695,700 x 50% = $347,850. The base is the greater of the two, so $347,850.

Step 3: Credit. ($695,700 minus $347,850) x 20% = $69,570.

Here the regular credit ($69,570) beats the ASC ($62,398), but the minimum base rule caps how far ahead it can get, and the regular credit needs gross receipts history and more substantiation. Run both every year and pick the better result, because the ASC election is made year by year on Form 6765.

A startup with no QREs in any one of the prior three years calculates the ASC as 6% of current-year QREs. Using the same $695,700 of 2025 QREs, but assuming this is the company's first year of research, the credit is $695,700 x 6% = $41,742.

That is $20,656 less than the $62,398 ASC above, which shows why history matters. The 14% rate only applies once you have three prior years with QREs, and a single empty year in that window drops you back to 6%.

Two practical points follow. First, claim the credit in every year you have QREs, even small ones, because a year with documented QREs keeps the 14% calculation available later. Second, the regular credit is still worth running in a first year, since its start-up company rules can produce a larger number for companies with modest gross receipts.

The ASC base rises every year because it is built from your own recent QREs, so growth in research spending matters more than its level. Continue the example into 2026 with QREs of $900,000 (hypothetical).

1. Prior three years: $500,000, $600,000 and $695,700. Average: $598,567.
2. Half of the average: $299,283.
3. Excess: $900,000 minus $299,283 = $600,717.
4. Credit: $600,717 x 14% = $84,100.

If 2026 QREs had stayed flat at $695,700, the credit would have been ($695,700 minus $299,283) x 14% = $55,498, lower than 2025 even though spending did not fall. Build this into forecasts so a flat engineering budget does not surprise anyone when the credit shrinks.

If the company is a qualified small business under §41(h), it can elect to apply the $62,398 against employer payroll taxes instead of waiting for taxable income. That requires gross receipts under $5 million for the year and no gross receipts before the five-year period ending with the year, which this example company would need to confirm.

The credit first reduces the employer's 6.2% Social Security tax, then the 1.45% Medicare tax, starting with the first quarter after the income tax return is filed. Counting only the six engineers, whose $140,000 average pay is below the Social Security wage base:

• Employer Social Security per quarter: $840,000 x 6.2% / 4 = $13,020.
• Employer Medicare per quarter: $840,000 x 1.45% / 4 = $3,045.
• Total offset available per quarter: $16,065.

At that pace, the $62,398 credit is used up in about four quarters. Payroll for other staff absorbs it faster. The election is made on Form 6765 with the timely filed return and carried to Form 941 on Form 8974.

Every input in this calculation needs support you could hand to an examiner. For the figures above, that means:

• Wages: payroll registers showing Form W-2 Box 1 wages for each engineer, plus a time allocation (sprint data, project codes or documented manager estimates) supporting the 70% qualified share.
• Contract research: the contracts, showing the work is performed in the United States and that you bear the risk and keep substantial rights, plus invoices.
• Cloud costs: invoices split between development or testing and production environments.
• Supplies: receipts for items consumed in research, excluding depreciable equipment.
• Base years: the same categories for each prior year, computed on a consistent basis, because the consistency rule requires base-period QREs to be measured the same way as current QREs.

For tax years beginning after December 31, 2024, §280C(c)(1) reduces your domestic research expense deduction under §174A by the full amount of the credit. In this example, claiming the $62,398 ASC credit reduces the §174A deduction by $62,398.

You can instead elect a reduced credit under §280C(c)(2) and keep the full deduction. The reduced credit is the credit minus the credit times the 21% corporate rate, or 79% of the gross amount: $62,398 x 79% = $49,294. The election must be made on a timely filed original return and cannot be revoked.

Which is better depends on whether you have taxable income now, how soon you expect to use NOLs, and whether you are applying the credit to payroll taxes. We model both before filing. This example is general information as of October 2026, not tax advice for your specific facts.