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Post-Award Budget Modification Calculator

Determine whether a proposed budget reallocation requires funder approval based on cumulative changes and approval thresholds.

About this calculator

Most grant funders — federal agencies especially, under 2 CFR 200.308 and their own award terms — let grantees shift money between budget categories without asking first, but only up to a threshold; the federal regulation itself sets that threshold at 10% of the total budget (including cost share) once cumulative transfers exceed it, for awards where the federal share is above the simplified acquisition threshold. This calculator's key insight is that the threshold applies to the cumulative change, not just what you're proposing today: it adds your proposed increase minus your proposed decrease to whatever modifications you've already made in that category, then compares the absolute value of that running total against the dollar threshold (your approval percentage times the original category budget). If the cumulative change exceeds the threshold, the calculator flags that prior written approval is required — even if today's specific request looks small, because it's the last straw on a series of smaller changes.

It also reports the modified category budget as a share of the total award, and a rough burn-rate comparison between the months elapsed and remaining in the grant period against the projected spending pace, though that projection is a simple proportional estimate rather than a real spend-down analysis. Two things trip people up: first, decreases count toward the threshold exactly like increases (the math is on absolute value); second, "approval threshold" percentages and rules vary by funder and by whether the change touches specific budget categories your award terms flag as more restrictive — always check your notice of award or grant agreement, since this tool applies a single threshold you supply (defaulting to 2 CFR 200.308's 10% figure) rather than any particular agency's actual policy.

Inputs

%

Results

Requires Prior Approval (0/1)

1

Cumulative Change (%)

20%

Modified Category Budget$60,000.00
Net Change (This Modification)$8,000.00
Cumulative Change ($)$10,000.00
Approval Threshold ($)$5,000.00
Remaining Before Approval$0.00
Category % of Total Award24%
Projected Remaining Spend$20,000.00
Expected Spend Rate33,333.33%

Figures current as of 2026. Source: 2 CFR 200.308 (Uniform Guidance), Revision of budget and program plans

How to Use This Calculator
  1. Enter the original budget line item amounts and any proposed modifications.
  2. Enter the funder's rebudgeting threshold percentage to determine if prior approval is required.
  3. Review line-by-line variances and the total budget modification amount.
  4. Check whether the modification crosses the prior approval threshold for the funder.
  5. Prepare a justification memo for each line modified and submit to the grants officer per program requirements.

What each input means

Original Category Budget ($)
Original approved budget for the category being modified.
Total Award Amount ($)
Total grant award amount across all categories.
Proposed Increase ($)
Amount you want to add to this category.
Proposed Decrease ($)
Amount you want to reduce from this category.
Prior Cumulative Modifications ($)
Net amount already modified in this category (positive = increases, negative = decreases).
Approval Threshold (%)
Cumulative change % that triggers prior approval requirement (typically 10-25%).
Remaining Grant Months
Months remaining in the grant period.
Total Grant Months
Total grant period in months.

What each result means

Requires Prior Approval (0/1)
1 = yes, cumulative changes exceed threshold; 0 = no, within allowable range.
Cumulative Change (%)
Cumulative modification as a percentage of original category budget.
Modified Category Budget
New budget after all modifications are applied.
Net Change (This Modification)
Net dollar change from this proposed modification.
Cumulative Change ($)
Total net change including prior modifications.
Approval Threshold ($)
Dollar amount at which prior approval is required.
Remaining Before Approval
How much more you can modify before needing approval.
Category % of Total Award
Modified category as percentage of total grant award.
Projected Remaining Spend
Estimated spending in remaining months at proportional rate.

How this is calculated

Worked example, using the default values

  1. Identify Input Parameters
    4 parameters
    Original Category Budget ($) = 50000, Total Award Amount ($) = 250000, Proposed Increase ($) = 8000, Proposed Decrease ($) = 0 = 8 input(s) provided
  2. Calculate Requires Prior Approval
    1 = 1
  3. Calculate Cumulative Change
    Cumulative Change = originalCategoryBudget > 0
    20 = 20%
  4. Calculate Modified Category Budget
    Modified Category Budget = originalCategoryBudget + cumulativeChange
    60000 = $60,000
  5. Calculate Net Change
    Net Change = proposedIncrease - proposedDecrease
    8000 = $8,000

Figures and sources

Engine last updated . Checked against 3 independently-derived tests — how we verify calculators. Built by Paul Gunder, a software engineer, not a licensed financial, medical, or legal professional.

Frequently Asked Questions

Why does a small proposed change still trigger the approval requirement?

Requires Prior Approval compares the absolute value of Cumulative Change — Prior Cumulative Modifications plus this modification's net change — against the dollar threshold, not just today's proposed amount in isolation. If you've already shifted $7,000 into a category with a $10,000 threshold and now propose another $4,000 increase, the cumulative total of $11,000 trips the threshold even though $4,000 alone wouldn't have. The tool is deliberately tracking the running total, not treating each request as a fresh start.

Does a decrease count the same as an increase toward the threshold?

Yes. Net Change is Proposed Increase minus Proposed Decrease, and everything downstream uses the absolute value of the resulting cumulative change. A $9,000 decrease pushes you toward the approval threshold exactly as fast as a $9,000 increase would, because federal Uniform Guidance treats moving money out of a category as significant a change as moving money in.

What is the burn-rate section actually estimating, and how reliable is it?

Projected Remaining Spend is the modified category budget multiplied by the fraction of the grant period still remaining (Remaining Grant Months / Total Grant Months) — a straight-line proportional estimate, not a model of your actual spending pattern. It assumes spending is evenly paced across the whole award period, which real grants rarely are (spending often front-loads for startup costs or back-loads near close-out), so treat it as a rough planning check, not a forecast.

Can I trust the Approval Threshold (%) default of 10% for my grant?

It's a reasonable starting point, not a guarantee. 2 CFR 200.308 itself sets 10% of the total budget (including cost share) as the trigger for prior written approval on cumulative transfers for federal awards where the federal share exceeds the simplified acquisition threshold, which is exactly why 10% is this calculator's default. But your specific notice of award, grant agreement, or agency-specific terms can set a different figure, and some budget categories (like equipment or key personnel) can carry stricter rules regardless of the overall percentage. Always enter the real threshold from your award documents rather than relying on the default.

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